fmt

Extend the metadata writers to binary-only uploads and wire them into
the 'pkh deb' flow:

- build/binary.rs generates <pkg>_<ver>_<arch>.buildinfo/.changes
  through any Context: debian/files consumption, encounter-order
  Architecture accumulation (sorted in .buildinfo like dpkg-genbuildinfo),
  sorted Binary lists, dpkg-formatted Description lines with udeb
  suffixes, Installed-Build-Depends closure over the context status DB,
  and binNMU handling (Source: pkg (prev), Binary-Only-Changes, previous
  .dsc redistribution);
- artifact digests are computed inside the context via coreutils
  (md5sum/sha1sum/sha256sum/stat) so chrooted/remote trees work;
- deb/local.rs runs the generation after 'rules binary', exports
  SOURCE_DATE_EPOCH from the changelog (reproducibility), and resolves
  vendor/profiles inside the context; deb/mod.rs retrieves the new
  artifacts alongside the debs;
- reusable helpers added: FilesList::parse/render,
  parse_changelog_entry_from_str, parse_previous_version_from_str,
  installed_build_depends_from_content.

Differential gate: same tree built with real 'dpkg-buildpackage -b' and
with the pkh flow; .changes/.buildinfo compared field-by-field modulo
machine-dependent fields, artifact checksums included.

plans/native-build.md

@@ -0,0 +1,328 @@
+# Native build pipeline — replacing the `dpkg-buildpackage` shell-out
+
+Status: **Phase 0 + Phase 1 (source builds) implemented** — see §11
+Reference codebase: https://salsa.debian.org/dpkg-team/dpkg (`main` branch, analyzed 2026-08)
+
+---
+
+## 0. TL;DR — honest take
+
+| Scope | Verdict | Effort | Risk |
+|---|---|---|---|
+| **A.** Re-implement the *orchestrator* ([`dpkg-buildpackage.pl`](https://salsa.debian.org/dpkg-team/dpkg/-/blob/main/scripts/dpkg-buildpackage.pl), 1209 lines of Perl) natively in Rust, still invoking `dpkg-source`, `debian/rules`, etc. as subprocesses | **Doable, worth it** | ~2–4 weeks | Low–medium |
+| **B.** Additionally replace the cheap satellite tools natively (`dpkg-parsechangelog`, `dpkg-checkbuilddeps`, `dpkg-architecture`, `dpkg-genchanges`, `dpkg-genbuildinfo`) | Doable incrementally | +1–2 weeks each | Medium |
+| **C.** Replace `dpkg-source` (tarball/diff generation, quilt integration, `.dsc` assembly) | **Not recommended** | 2–3+ months, then endless edge cases | High |
+
+The key insight: `dpkg-buildpackage` itself is a thin (~1200-line) Perl *sequencer*. The real complexity lives in `dpkg-source` (~4000 lines of Perl across `Dpkg/Source/*`). A source build fundamentally requires `dpkg-source`-class functionality (orig tarballs, debian diffs, `.dsc` assembly), so "no dpkg tools at all" is not a realistic goal — but "no `dpkg-buildpackage`, full control of the pipeline" absolutely is, and it unlocks things pkh currently cannot do (live UI on source builds, `.changes`/`.buildinfo` generation on binary builds, unified error classification).
+
+---
+
+## 1. Where pkh stands today
+
+Two divergent build paths:
+
+### Source builds — [`build_source_package()`](../src/build/mod.rs)
+Shelled out on the host:
+```
+dpkg-buildpackage -S -I -i -nc -d [--sign-keyid=<id> | --no-sign]
+```
+Problems:
+- Requires `dpkg-dev` on the host.
+- Output bypasses the live UI entirely ([`DebUi`](../src/ui/deb.rs) / [`LineSink`](../src/context/mod.rs)) — no phase tracking, no log classification, unlike binary builds.
+- No control over failure semantics beyond exit status.
+
+### Binary builds — [`deb::local::build()`](../src/deb/local.rs)
+Already does **not** use `dpkg-buildpackage`. Hand-rolled sequence: ephemeral unshare chroot → `apt-get update` → essentials → manual `quilt push -a` → `apt-get build-dep` → `debian/rules build` → `fakeroot debian/rules binary` → retrieve `.deb`s.
+What it silently skips compared to a real build:
+- `debian/rules clean` before building,
+- `dpkg-source --before-build/--after-build` lifecycle (it re-implements patch application crudely),
+- `.buildinfo` and `.changes` generation,
+- build-conflicts checking, `Rules-Requires-Root` semantics,
+- `SOURCE_DATE_EPOCH` export (reproducibility).
+
+So pkh already pays part of the "native orchestrator" cost without getting its benefits. A native implementation would unify both paths.
+
+### Existing native assets to reuse
+- Changelog header/footer parsing — [`changelog.rs`](../src/changelog.rs) (needs extension to full metadata: timestamp, urgency, trailer key/values).
+- GPG key discovery — [`utils/gpg.rs`](../src/utils/gpg.rs) via `gpgme`.
+- Hashing crates already present: `sha2`, `md-5` (need to add `sha1`); compression: `flate2`, `xz2`; archives: `tar`.
+- Command execution through remote-capable contexts — [`ContextCommand`](../src/context/mod.rs) (local/ssh/schroot/unshare/capture).
+- Live UI phases — [`ui/deb.rs`](../src/ui/deb.rs).
+
+---
+
+## 2. What `dpkg-buildpackage` actually is (measured)
+
+It is a Perl script (`use v5.36`). Measured sizes on `main`:
+
+| Component | Lines | Role |
+|---|---|---|
+| `scripts/dpkg-buildpackage.pl` | 1209 | Orchestrator |
+| `scripts/dpkg-source.pl` | 806 | Driver; work in `Dpkg/Source/*` |
+| `scripts/dpkg-genbuildinfo.pl` | 637 | `.buildinfo` generation |
+| `scripts/dpkg-genchanges.pl` | 626 | `.changes` generation |
+| `scripts/dpkg-architecture.pl` | 498 | Arch name/triplet tables |
+| `scripts/dpkg-gensymbols.pl` | 398 | (called by rules, not by us) |
+| `scripts/dpkg-checkbuilddeps.pl` | 270 | Dep checking vs status file |
+| `scripts/dpkg-parsechangelog.pl` | 195 | Changelog CLI wrapper |
+| `scripts/dpkg-distaddfile.pl` | 99 | Registers files in `debian/files` |
+| `Dpkg/*.pm` + `Dpkg/Source/*.pm` (subset examined) | ~11,600 | Shared library code |
+
+Total relevant Perl surface ≈ **16k LOC**, of which the orchestrator is only ~8%.
+
+---
+
+## 3. The exact pipeline (verified against source)
+
+What `dpkg-buildpackage` does, in order:
+
+1. **Config**: load `buildpackage.conf` (Dpkg::Conf), inject as leading argv.
+2. **Option parsing** (~200 lines): build types `-F/-g/-G/-b/-B/-A/-S` (+ `--build=full,source,binary,any,all`), signing (`-us/-uc/-ui/-k/-p/--no-sign/--force-sign`), `-j/-J/--jobs-force`, `-r<root-cmd>`, `-R<rules>`, `-T<targets>`, `-a/-t/--target-arch`, `-P<profiles>`, `-d/-D`, `-nc/-tc`, hooks `--hook-<name>=<cmd>`, passthrough buckets for `dpkg-source` / `dpkg-genchanges` / `dpkg-genbuildinfo`.
+3. **Build type → rules targets**: `binary`→`build`+`binary`; arch-dep only→`build-arch`+`binary-arch`; indep only→`build-indep`+`binary-indep`.
+4. **Implied flags**: `-nc` alone implies `-b`; `-nc -S` disables build-dep checks.
+5. **Environment prep**:
+   - `parallel=auto` default → `DEB_BUILD_OPTIONS=parallel=N` exported;
+   - forced jobs additionally appended to `MAKEFLAGS`;
+   - `DEB_BUILD_PROFILES` exported if `-P`;
+   - optional `.dsc` input → `dpkg-source --extract` first;
+   - `SOURCE_DATE_EPOCH ||= changelog timestamp || time()` (reproducible-builds.org spec);
+   - full env dump of `dpkg-architecture -f [-a…][-t…]` imported into the environment (all `DEB_BUILD_*`, `DEB_HOST_*`, `DEB_TARGET_*` incl. `*_OS/CPU/MULTIARCH/GNU_TYPE/ARCH_BITS/ENDIAN`);
+   - OpenPGP key resolution: `--sign-keyfile` > `--sign-keyid` > maintainer userid; secrets probed up-front; **UNRELEASED distribution ⇒ signing disabled** unless `--force-sign`.
+6. **Pre-flight**: `Dpkg::BuildDriver->pre_check()` (rules file exists/executable); `dpkg-source --before-build .` (applies patches for quilt formats); `dpkg-checkbuilddeps [-A|-B|-I]` unless `-d` (exit 3 on unmet).
+7. **Hooks** at 12 points: `preinit init preclean source build binary buildinfo changes postclean check sign done`, with `%p/%v/%s/%u/%a` substitution.
+8. **Preclean**: `debian/rules clean` via BuildDriver (gain-root per `Rules-Requires-Root`).
+9. **Source build** (if any SOURCE component): `dpkg-source -b .` → `.dsc` + tarballs in `..`.
+10. **Binary build** (if any BINARY component): `run_build_task(build-target)` then `binary-target` through BuildDriver (RRR-aware root command; skips separate non-root `build` pass when running rootless).
+11. **Metadata generation**:
+    - `dpkg-genbuildinfo` → `../<pkg>_<ver_noepoch>_<arch>.buildinfo` (Format 1.0; records `Installed-Build-Depends` snapshot from the dpkg status DB, build environment, checksums);
+    - `dpkg-genchanges` → `../<pkg>_<ver_noepoch>_<arch>.changes` (Format 1.8; aggregates `debian/files` + changelog + control).
+12. **Post**: optional `-tc` clean; `dpkg-source --after-build .` (unapplies patches it applied); human summary ("full upload (original source is included)" etc. derived from the `Files` field); optional lintian-style check command.
+13. **Signing cascade** (inline/clearsig via OpenPGP backend gpg|sequoia|sop):
+    - sign `<pkg>_<ver>.dsc` → recompute its checksums **inside `.buildinfo`**;
+    - sign `.buildinfo` → recompute dsc+buildinfo checksums **inside `.changes`** (rewriting both `Checksums-*` and legacy `Files` entries);
+    - sign `.changes`.
+
+Exit codes matter: e.g. unsatisfied build-deps ⇒ exit 3.
+
+---
+
+## 4. Sub-tool inventory and replacement strategy
+
+| Tool | Used for | Complexity to replace natively | Strategy |
+|---|---|---|---|
+| `dpkg-parsechangelog` | source/version/maintainer/distribution/timestamp | **Low** — documented format; crates exist (`debian-changelog`, `deb822-parser` ecosystem) | Replaced (see §11, [`metadata.rs`](../src/build/metadata.rs)) |
+| `dpkg-version` compare | epoch/upstream/revision ordering | **Low** — small well-specified algorithm; crate `debversion` | **Replaced** (§11, [`debian/version.rs`](../src/debian/version.rs): `Ord`/`compare`/`later_than`) |
+| `dpkg-architecture` | arch ↔ triplet tables, multiarch tuple, env dump | **Low-medium** — embed cputable/ostable/tupletable/abitable data (stable for years) | **Replaced** (§11, [`debian/arch.rs`](../src/debian/arch.rs)) |
+| `dpkg-checkbuilddeps` | deps vs installed status | **Medium** — `Dpkg::Deps` grammar (alternatives, arch qualifiers, `<profiles>` restrictions, versioned Provides subtleties, Multi-Arch facts) + status-file scan | **Replaced** (§11, [`debian/deps.rs`](../src/debian/deps.rs); wired into the pipeline behind `-D`, source-only builds skip it like dpkg-buildpackage) |
+| `dpkg-genbuildinfo` | `.buildinfo` | **Medium** — deb822 emit + status snapshot + checksums | Native (see §11, [`buildinfo.rs`](../src/build/buildinfo.rs)) |
+| `dpkg-genchanges` | `.changes` | **Medium** — deb822 emit + `debian/files` consumption + `.deb` control extraction (ar+tar, trivial with crates) | **Replaced** for source (§11) and binary uploads (§11, [`build/binary.rs`](../src/build/binary.rs)) |
+| `dpkg-genbuildinfo` (binary) | `.buildinfo` for `-b` builds | **Medium** — deb822 emit + in-context artifact hashing | **Replaced** (§11, [`build/binary.rs`](../src/build/binary.rs), wired into [`deb/local.rs`](../src/deb/local.rs)) |
+| `dpkg-distaddfile`/`debian/files` protocol | build outputs registry | **Trivial** — one append-only line format | Native ([`files.rs`](../src/build/files.rs)) |
+| OpenPGP signing | inline clearsign of dsc/buildinfo/changes | **Low** — `gpgme` (already a dependency) supports clearsigning | Native ([`sign.rs`](../src/build/sign.rs)) |
+| `dpkg-source` | orig tarball, debian diff, patches, `.dsc` | **Very high** — V1/V2/quilt/native formats, byte-exact tar normalization, quilt bookkeeping, `--include-binaries`, hundreds of validation warnings | **Keep as subprocess** (see §6) |
+| `debian/rules` execution | the actual build | N/A (foreign code) | Keep, via `ContextCommand` |
+
+---
+
+## 5. Feasibility detail per scope
+
+### Scope A — native orchestrator (recommended)
+
+The 1209-line script decomposes into clean Rust pieces:
+
+```
+src/build/
+├── mod.rs          // pipeline driver (the equivalent of main())
+├── buildtype.rs    // BUILD_SOURCE|ARCH_DEP|ARCH_INDEP bitflags + target mapping
+├── metadata.rs     // changelog + control resolution, version splitting
+├── env.rs          // SOURCE_DATE_EPOCH, DEB_BUILD_OPTIONS, arch env dump
+├── buildinfo.rs    // native .buildinfo writer
+├── changes.rs      // native .changes writer
+├── files.rs        // debian/files registry emulation
+├── checksums.rs    // md5/sha1/sha256 registry
+├── control.rs      // deb822 parser/writer
+└── sign.rs         // gpgme clearsign + post-sign checksum cascade
+```
+
+Estimated ~1.5–3 kLOC. Everything is deterministic file munging + subprocess sequencing — no daemons, no parsing of arbitrary upstream code (that's `dpkg-source`'s job, which we keep).
+
+**pkh-specific simplifications** (legitimate because pkh controls the environment):
+- Builds run as **real root** inside ephemeral unshare chroots ⇒ the entire gain-root/fakeroot matrix collapses: run `debian/rules` directly when the context is root (keep `fakeroot` fallback for host-side source builds).
+- pkh's option surface is a fraction of dpkg's: `-S/-b/-B/-A/-g/-G`, `-us/-uc`, `-k`, `-j`, `-a`, `-P`, `-d/-D`, `-nc/-tc`, `-R`, `-T` cover everything pkh passes today plus obvious headroom. Hooks and `--hook-*` can be dropped initially.
+- Vendor hooks (`run_vendor_hook`) are rarely used in the build path; Ubuntu/Debian differences pkh cares about are already handled via [`distro_info.yml`](../distro_info.yml).
+
+**What this buys pkh concretely:**
+1. Live UI + log classification for source builds (today's `-S` path is a black box).
+2. `.changes`/`.buildinfo` for binary builds — currently missing entirely; needed for uploads/PPA submissions and lintian checks.
+3. Correct `dpkg-source --before-build/--after-build` lifecycle replacing the manual `quilt push -a` hack in [`local.rs`](../src/deb/local.rs) (handles `3.0 (quilt)` properly, incl. unapply-on-exit and format detection instead of sniffing `debian/patches/series`).
+4. `SOURCE_DATE_EPOCH` reproducibility for free.
+5. No host `dpkg-dev` requirement for orchestration decisions; `dpkg-source` still needed inside build environments where pkh already installs packages anyway.
+
+### Scope B — satellite tools
+
+Incremental, each independently testable against the real tool (differential testing). Crates from the `rust-debian-*` ecosystem (maintained by Jelmer Vernooij) cover most parsing: `deb822-parser`, `debian-control`, `debian-changelog`, `debversion`. Priority order if pursued: version compare → changelog → architecture tables → checkbuilddeps.
+
+### Scope C — `dpkg-source`
+
+The honest numbers: `Dpkg/Source/Package/V2.pm` alone is 847 lines, V1 is 599, plus Archive/Quilt/Functions/BinaryFiles modules, GNU diff generation, and — critically — **byte-level tar normalization** (mtime/uid/gid/mode canonicalization, pax header handling) that reproducible builds depend on. Parity means being bug-compatible with dpkg against ~40k archive source packages. This is a multi-month project with a long tail, and it buys pkh almost nothing since `dpkg-source` is guaranteed present inside the very chroots pkh creates. **Do not do this.**
+
+---
+
+## 6. Proposed phasing
+
+### Phase 0 — quick win (days)
+Route the existing `dpkg-buildpackage -S` call through the UI capture machinery (like [`cap()`](../src/deb/local.rs) does for binary builds): phase display + `LineSink` classification. No behavior change otherwise.
+
+### Phase 1 — native orchestrator (2–4 weeks)
+Implement §5 scope A. Both entry points converge:
+- `pkh build -S` → native pipeline, `dpkg-source -b` subprocess, native signing.
+- `pkh build` (binary) → same pipeline skeleton inside the ephemeral context: preclean → before-build → dep check → `rules build` → `rules binary[-arch|-indep]` → native buildinfo/changes → after-build. Deletes the manual quilt logic.
+
+Deliverables:
+- `src/build/*` module tree (§5).
+- Native `.buildinfo` (Format 1.0) and `.changes` (Format 1.8) writers emitting exactly the field sets observed in `dpkg-genbuildinfo.pl` / `dpkg-genchanges.pl`, in dpkg's canonical field order:
+  - buildinfo: `Format, Source, Binary, Architecture, Version, Binary-Only-Changes, Checksums-Md5/Shа1/Sha256, Build-Origin, Build-Architecture, Build-Kernel-Version(opt), Build-Date, Build-Path(opt), Build-Tainted-By(opt), Installed-Build-Depends, Environment`
+  - changes: `Format, Date, Source, Binary, Built-For-Profiles, Architecture, Version, Distribution, Urgency, Maintainer, Changed-By, Description, Changes, Checksums-Sha1/Sha256, Files`
+- Post-signature checksum cascade implemented exactly as dpkg does (sign dsc → patch buildinfo checksums → sign buildinfo → patch changes `Files`+`Checksums-*` → sign changes).
+- Differential test harness (§8).
+
+### Phase 2 — satellite replacement (optional, incremental)
+Swap subprocesses for native implementations, one tool at a time, gated by differential tests. Start with version-compare + changelog (already half-present in pkh).
+
+### Explicitly out of scope
+`dpkg-source` internals, `dpkg-deb` packing, apt resolution (pkh correctly delegates to `apt-get build-dep` + dose3 for explanations already).
+
+---
+
+## 7. Tricky details to get right (gotchas list)
+
+1. **Version splitting**: `<epoch:>upstream<-revision>`; `.dsc`/tarball names use *upstream* portion without epoch; `.changes` name uses version **without epoch** but **with revision** (`$sversion` in the script).
+2. **`-nc` implication chain**: `-nc` ⇒ binary build implied; `-nc -S` ⇒ no dep check.
+3. **UNRELEASED** ⇒ auto-disable all signing (warn), `--force-sign` overrides.
+4. **Signing invalidates checksums transitively** (dsc → buildinfo → changes); get the cascade order right or archive tools reject the upload.
+5. **`debian/files`** is the contract between `debian/rules` (via `dh_builddeb`/`dpkg-gencontrol`/`dpkg-distaddfile`) and the changes generator: lines of `filename section priority [key=value...]`.
+6. **Arch selection for names**: `arch` suffix in artifact filenames is `host-arch` for arch-dep builds, `all` for indep-only, `source` for source-only.
+7. **`dpkg-source --before-build` must run even for binary-only builds** (patch application), and `--after-build` at the end — this replaces pkh's current manual quilt step and fixes `3.0 (quilt)` correctness.
+8. **Environment parity**: `dpkg-architecture -f` dump must be imported wholesale (not cherry-picked) — packages test `DEB_HOST_GNU_TYPE`, `DEB_BUILD_MULTIARCH`, `DEB_BUILD_ARCH_ENDIAN`, etc. If embedding tables later, mirror the full variable set.
+9. **Exit codes**: preserve dpkg conventions (3 = unmet build-deps) so wrappers/scripts behave identically.
+10. **Locale**: dpkg sets `LANG=C`-ish determinism for subprocesses — pkh already does this in [`local.rs`](../src/deb/local.rs); keep for all pipeline steps.
+11. **Multiline field rendering**: values starting with `\n` render as `Field:` + indented continuation lines (no inline first line, no trailing space) — this is how dpkg emits `Changes`, `Files`, `Installed-Build-Depends`, `Environment`.
+12. **Artifact ordering** in `Checksums-*`/`Files` is insertion order (dsc → tarballs in dsc-field order → debs → buildinfo), not alphabetical.
+
+---
+
+## 8. Testing strategy
+
+- **Differential harness**: run real `dpkg-buildpackage` and the native pipeline over a corpus (packages covering: `1.0` non-native, `3.0 (quilt)` with/without patches, native, binaries-only, indep-only, cross, RRR variants, UNRELEASED) and diff artifacts modulo timestamps/signatures.
+- **Port unit cases** from dpkg's own `t/` tests for version compare, deps parsing, changelog parsing.
+- **Golden-file tests** for `.changes`/`.buildinfo` writers.
+- Pin the reference dpkg version in CI commentary (behavior drift across dpkg releases is the main maintenance cost).
+
+---
+
+## 9. Risks
+
+| Risk | Mitigation |
+|---|---|
+| Behavior drift vs future dpkg releases (new fields, format bumps) | Differential tests pinned to a reference version; changes/buildinfo formats are extremely stable (1.8 / 1.0 for years) |
+| Archive/upload tooling rejects our `.changes`/`.buildinfo` | Validate with `lintian` + a real PPA upload early in Phase 1 |
+| License contamination | dpkg is GPL-2+. Write from documented behavior/format specs and observation, **do not transliterate Perl**; alternatively accept GPL for pkh (currently no license field in [`Cargo.toml`](../Cargo.toml) — decision needed) |
+| Scope creep toward Scope C | Hard rule: `dpkg-source` stays a subprocess |
+| Remote-context divergence | All tree-touching steps go through [`ContextCommand`](../src/context/mod.rs); metadata steps operate on locally-synced copies like [`changelog.rs`](../src/changelog.rs) already does |
+
+---
+
+## 10. Effort summary
+
+| Item | Estimate |
+|---|---|
+| Phase 0 (UI capture for `-S`) | 1–2 days |
+| Phase 1 (native orchestrator + buildinfo/changes/signing) | 2–4 weeks |
+| Phase 2 per satellite tool | 3 days – 2 weeks each |
+| Scope C (`dpkg-source`) | 2–3+ months — rejected |
+
+Bottom line: **yes, it's doable — for the orchestrator.** Treat `dpkg-source` as a permanent subprocess dependency, and the task becomes a well-bounded, high-value refactor that also fixes real gaps in pkh's binary path.
+
+---
+
+## 11. Implementation status (Phase 1 — source builds)
+
+Landed in `src/build/` (~2.8 kLOC incl. tests), wired behind the historical
+entry point [`build_source_package()`](../src/build/mod.rs) so `pkh build`
+now runs the native pipeline:
+
+| Module | Role |
+|---|---|
+| [`control.rs`](../src/build/control.rs) | deb822 paragraph parser/writer (dpkg-compatible multiline rendering) |
+| [`checksums.rs`](../src/build/checksums.rs) | md5/sha1/sha256 registry, insertion-ordered like dpkg's artifact accumulation |
+| [`metadata.rs`](../src/build/metadata.rs) | version splitting/validation, full changelog entry parse (incl. binNMU `binary-only`), control info |
+| [`buildtype.rs`](../src/build/buildtype.rs) | build-type bitflags + rules-target/artifact-suffix mapping |
+| [`env.rs`](../src/build/env.rs) | `SOURCE_DATE_EPOCH`, `DEB_BUILD_OPTIONS`, `dpkg-architecture` env dump, vendor/profiles, sanitized `Environment` field |
+| [`files.rs`](../src/build/files.rs) | `debian/files` registry (parse/atomic save) |
+| [`buildinfo.rs`](../src/build/buildinfo.rs) | `.buildinfo` writer + `Installed-Build-Depends` closure over the dpkg status DB |
+| [`changes.rs`](../src/build/changes.rs) | `.changes` writer (canonical field order, legacy `Files` + `Checksums-Sha1/256`) |
+| [`sign.rs`](../src/build/sign.rs) | gpgme clearsigning + key-id validation |
+
+Still delegated to subprocesses: `dpkg-source -b/--before-build/--after-build`
+(by design, see §5 Scope C).
+
+**Differential validation** — automated in
+[`build/mod.rs`](../src/build/mod.rs) (`mod differential_tests`, runs by
+default with `cargo test --lib`):
+
+- a corpus of 12 synthetic fixtures covering: native/quilt/1.0 formats,
+  epochs, `~` pre-releases, Ubuntu/Debian series (focal, noble, jammy,
+  trixie, unstable), high urgency, multiple binary stanzas, one/two quilt
+  patches, binNMU (`binary-only=yes` + previous-entry metadata),
+  `(Closes: #…)` extraction, UNRELEASED no-sign, extra source-stanza fields;
+- each case builds the tree twice (`cp -a` copies) — once with real
+  `dpkg-buildpackage -S -I -i -nc -d --no-sign`, once with the native
+  pipeline — then compares:
+  - `.dsc` payload byte-for-byte,
+  - `.changes` field-by-field (checksum lines of the `.buildinfo` itself
+    excluded),
+  - `.buildinfo` structure (machine-dependent fields excluded);
+- real **archive packages** are pulled with pkh's own
+  [`pull`](../src/pull.rs) (archive download mode) and compared the same
+  way, via [`differential_real_archive_package()`](../src/build/mod.rs)
+  which takes `(package, dist, series)`:
+  - always-on CI tests: `hello` @ ubuntu/noble, `dosfstools` @
+    debian/trixie, `sl` @ ubuntu/focal;
+  - an additional `#[ignore]`-gated test for ad-hoc broad runs:
+    ```text
+    PKH_DIFF_PACKAGES="bash coreutils curl" PKH_DIFF_DIST=ubuntu \
+    PKH_DIFF_SERIES=noble cargo test --lib \
+        differential_real_archive_packages -- --ignored
+    ```
+  (requires network access).
+
+Manual validation additionally confirmed: signed builds verify with
+`gpg --verify` on all three artifacts; the patch apply/unapply lifecycle is
+correct for quilt formats.
+
+**Known divergences** (documented, all informational fields): no
+`Build-Tainted-By` (vendor hook), no `dpkg-buildflags` origin tracking in the
+`Environment` field, vendor default profiles approximated
+(`derivative.ubuntu noudeb` for Ubuntu).
+
+## 12. Implementation status (Phase 2 — satellite tools)
+
+All four satellite replacements landed, each gated by differential tests
+against the real tool:
+
+| Work item | Module | Differential gate |
+|---|---|---|
+| WI-1 `dpkg-architecture` | [`debian/arch.rs`](../src/debian/arch.rs) (tables + lookups), wired into [`build/env.rs`](../src/build/env.rs) | `arch_env(Some(a))` equals real `dpkg-architecture -f -a a` key-for-key for **every** arch from `dpkg-architecture -L`, plus native (`build/mod.rs::diff_arch_env_*`) |
+| WI-2 version compare | [`debian/version.rs`](../src/debian/version.rs) (`Ord`, `compare`, `later_than`) | all vectors from dpkg `scripts/t/Dpkg_Version.t` + Ubuntu-flavored cases, cross-checked against `dpkg --compare-versions` for `<< <= = >= >>` (`diff_version_compare_against_dpkg`) |
+| WI-3 `dpkg-checkbuilddeps` | [`debian/deps.rs`](../src/debian/deps.rs) (grammar, restriction reduction, KnownFacts evaluation, `check_build_depends`) | 24 scenarios vs real `dpkg-checkbuilddeps` (alternatives, versions, arch/profile restrictions, Multi-Arch, versioned Provides, conflicts, `-A`/`-B`) comparing exit status + diagnostics (`diff_checkbuilddeps_matrix`); unit tests port the `Dpkg_Deps.t` reduction matrices. Wired into `run_source_build` behind `-D` parity: source-only builds skip the check like `dpkg-buildpackage`, unsatisfied deps exit 3 |
+| WI-4 binary `.buildinfo`/`.changes` | [`build/binary.rs`](../src/build/binary.rs) (context-generic generation), wired into [`deb/local.rs`](../src/deb/local.rs); artifact retrieval extended in [`deb/mod.rs`](../src/deb/mod.rs) | same tree built with real `dpkg-buildpackage -b` and with the pkh flow (rules build/binary + native metadata through a local context): `.changes`/`.buildinfo` compared field-by-field modulo machine-dependent fields, artifact checksums included (`diff_binary_build_metadata`) |
+
+Binary-flow notes: `SOURCE_DATE_EPOCH` is now exported to the rules
+environment (reproducibility); digests are computed inside the context via
+coreutils so remote/chrooted trees work; binNMU binary builds set
+`Source: pkg (prev)` / `Binary-Only-Changes` and redistribute the previous
+`.dsc` when present; `Architecture` is encounter-ordered in `.changes`
+(sorted in `.buildinfo`, matching dpkg).
+
+Still delegated to subprocesses: `dpkg-source` and `debian/rules` (by
+design, see §5 Scope C).

src/build/binary.rs

@@ -0,0 +1,475 @@
+//! Binary-build metadata generation: native `.buildinfo` / `.changes`
+//! production for binary-only builds (`pkh deb`), the equivalent of
+//! `dpkg-genbuildinfo -b` + `dpkg-genchanges -b`.
+//!
+//! All tree/database access goes through a [`Context`] so the generation can
+//! run against a build tree living in a local directory, an ephemeral
+//! chroot or a remote host. Artifact digests are computed inside the context
+//! with coreutils (`md5sum`, `sha1sum`, `sha256sum`, `stat`), keeping the
+//! flow binary-safe regardless of the transport.
+
+use std::collections::BTreeMap;
+use std::error::Error;
+use std::path::{Path, PathBuf};
+use std::sync::Arc;
+
+use crate::context::Context;
+use crate::debian::{
+    ChecksumEntry, ControlInfo, FileChecksums, FilesList, parse_changelog_entry_from_str,
+};
+
+/// Digests of one artifact.
+#[derive(Debug, Clone, Default)]
+struct ArtifactHashes {
+    size: u64,
+    md5: String,
+    sha1: String,
+    sha256: String,
+}
+
+/// Options driving binary metadata generation.
+#[derive(Debug, Clone)]
+pub struct BinaryMetadataOptions {
+    /// Active build profiles (`Built-For-Profiles`).
+    pub profiles: Vec<String>,
+    /// Vendor name (`Build-Origin`).
+    pub vendor: String,
+    /// Parallel job count advertised in `DEB_BUILD_OPTIONS`.
+    pub parallel: usize,
+    /// Reproducible-builds epoch exported to the build.
+    pub source_date_epoch: i64,
+    /// Build architecture (the machine inside the build context).
+    pub build_arch: String,
+    /// Host architecture (the packages' target); equals the build
+    /// architecture except for cross builds.
+    pub host_arch: String,
+}
+
+/// Generate `<pkg>_<ver>_<arch>.buildinfo` and `.changes` for a finished
+/// binary build, consuming `debian/files` from `package_dir` and the
+/// artifacts sitting in `upload_dir`. Returns both paths (inside the
+/// context).
+///
+/// Mirrors the observable behavior of `dpkg-genbuildinfo -b` and
+/// `dpkg-genchanges -b`: sorted `Binary` list, encounter-order `Architecture`
+/// accumulation, sorted `Description` lines formatted like dpkg, `.buildinfo`
+/// registration in `debian/files`, and binary-NMU handling (`Source:
+/// pkg (prev)` + previous `.dsc` redistribution when present).
+pub fn generate_binary_metadata(
+    ctx: &Arc<Context>,
+    package_dir: &Path,
+    upload_dir: &Path,
+    opts: &BinaryMetadataOptions,
+) -> Result<(PathBuf, PathBuf), Box<dyn Error>> {
+    // ------------------------------------------------------------------
+    // Metadata sources inside the context
+    // ------------------------------------------------------------------
+    let changelog_content = ctx.read_file(&package_dir.join("debian/changelog"))?;
+    let entry = parse_changelog_entry_from_str(&changelog_content)?;
+
+    let control_content = ctx.read_file(&package_dir.join("debian/control"))?;
+    let control = ControlInfo::parse_content(&control_content)?;
+
+    let files_content = ctx
+        .read_file(&package_dir.join("debian/files"))
+        .unwrap_or_default();
+    let mut files_list = FilesList::parse(&files_content)?;
+
+    // ------------------------------------------------------------------
+    // Collect binary artifacts registered in debian/files
+    // ------------------------------------------------------------------
+    let artifact_names: Vec<String> = files_list
+        .iter()
+        .filter(|e| matches!(e.package_type.as_deref(), Some("deb") | Some("udeb")))
+        .map(|e| e.filename.clone())
+        .collect();
+
+    if artifact_names.is_empty() {
+        return Err("binary build with no binary artifacts found; cannot distribute".into());
+    }
+
+    let mut hashes = hashes_in_context(ctx, upload_dir, &artifact_names)?;
+
+    let mut checksums = FileChecksums::new();
+    let mut arch_values: Vec<String> = Vec::new();
+    let mut arch_seen = std::collections::HashSet::new();
+    for name in &artifact_names {
+        let entry_hashes = hashes
+            .remove(name)
+            .ok_or_else(|| format!("artifact '{name}' listed in debian/files but not found"))?;
+        checksums.insert_entry(
+            name,
+            ChecksumEntry {
+                size: entry_hashes.size,
+                md5: entry_hashes.md5,
+                sha1: entry_hashes.sha1,
+                sha256: entry_hashes.sha256,
+            },
+        );
+        // Architecture accumulation in encounter order (dpkg-genchanges).
+        if let Some(file_entry) = files_list.get(name)
+            && let Some(arch) = file_entry
+                .arch
+                .as_ref()
+                .or_else(|| file_entry.attrs.get("architecture"))
+            && arch_seen.insert(arch.clone())
+        {
+            arch_values.push(arch.clone());
+        }
+    }
+
+    // ------------------------------------------------------------------
+    // Binary-NMU: redistribute the previous source when present
+    // ------------------------------------------------------------------
+    let sversion = entry.version.no_epoch();
+    let mut source_display = entry.source.clone();
+    let mut binary_only_changes = None;
+
+    if entry.binary_only
+        && let Ok(prev_entry) = crate::debian::changelog::parse_previous_version_from_str(
+            &ctx.read_file(&package_dir.join("debian/changelog"))?,
+        )
+        && let Some(prev) = prev_entry
+    {
+        source_display = format!("{} ({})", entry.source, prev);
+        binary_only_changes = Some(format!(
+            "{}\n\n -- {} <{}>  {}",
+            entry.changes_field, entry.maintainer_name, entry.maintainer_email, entry.date_raw
+        ));
+        let prev_version = crate::debian::DebianVersion::parse(&prev)?;
+        let dsc_name = format!("{}_{}.dsc", entry.source, prev_version.no_epoch());
+        let dsc_path = upload_dir.join(&dsc_name);
+        if ctx.exists(&dsc_path)? {
+            include_dsc_artifacts(ctx, upload_dir, &dsc_name, &mut checksums)?;
+        }
+    }
+
+    // ------------------------------------------------------------------
+    // Binary package names and descriptions
+    // ------------------------------------------------------------------
+    let mut binaries: Vec<String> = Vec::new();
+    for name in &artifact_names {
+        if let Some(e) = files_list.get(name)
+            && let Some(pkg) = &e.package
+            && !binaries.contains(pkg)
+        {
+            binaries.push(pkg.clone());
+        }
+    }
+    binaries.sort();
+
+    // Description lines: first line of each binary stanza's Description,
+    // formatted exactly like dpkg-genchanges, sorted.
+    let mut descriptions = Vec::new();
+    for stanza in &control.binaries {
+        let Some(pkg) = stanza.get("Package") else {
+            continue;
+        };
+        if !binaries.contains(&pkg.to_string()) {
+            continue;
+        }
+        let summary = stanza
+            .get("Description")
+            .unwrap_or("no description available")
+            .lines()
+            .next()
+            .unwrap_or("no description available");
+        // Package-Type overrides the artifact-derived type (deb default).
+        let pkg_type = stanza
+            .get("Package-Type")
+            .map(str::to_string)
+            .unwrap_or_else(|| {
+                files_list
+                    .iter()
+                    .find(|f| f.package.as_deref() == Some(pkg))
+                    .and_then(|f| f.package_type.clone())
+                    .unwrap_or_else(|| "deb".to_string())
+            });
+        descriptions.push(crate::build::changes::format_description(
+            pkg, &pkg_type, summary,
+        ));
+    }
+    descriptions.sort();
+
+    // ------------------------------------------------------------------
+    // Installed-Build-Depends closure over the context status database
+    // ------------------------------------------------------------------
+    let status_content = ctx
+        .read_file(Path::new("/var/lib/dpkg/status"))
+        .unwrap_or_default();
+    let bd_fields = [
+        control.source.get("Build-Depends").unwrap_or(""),
+        control.source.get("Build-Depends-Arch").unwrap_or(""),
+        control.source.get("Build-Depends-Indep").unwrap_or(""),
+    ];
+    let installed_build_depends =
+        crate::build::buildinfo::installed_build_depends_from_content(&status_content, &bd_fields)?;
+
+    // ------------------------------------------------------------------
+    // .buildinfo generation, then registration in debian/files
+    // ------------------------------------------------------------------
+    let pipeline_env = pipeline_environment(opts);
+    let environment = crate::build::env::buildinfo_environment(&pipeline_env);
+
+    // dpkg-genbuildinfo sorts the accumulated architecture values, while
+    // dpkg-genchanges keeps encounter order.
+    let mut buildinfo_arch_values = arch_values.clone();
+    buildinfo_arch_values.sort();
+
+    let buildinfo_name = format!("{}_{}_{}.buildinfo", entry.source, sversion, opts.host_arch);
+    let buildinfo_doc =
+        crate::build::buildinfo::render_buildinfo(&crate::build::buildinfo::BuildInfoInput {
+            source: source_display.clone(),
+            binaries: binaries.clone(),
+            architecture: buildinfo_arch_values.join(" "),
+            version: entry.version.full(),
+            binary_only_changes: binary_only_changes.clone(),
+            build_origin: opts.vendor.clone(),
+            build_architecture: opts.build_arch.clone(),
+            build_date: chrono::Local::now().to_rfc2822(),
+            checksums: checksums.clone(),
+            installed_build_depends,
+            environment,
+        });
+    let buildinfo_path = upload_dir.join(&buildinfo_name);
+    ctx.write_file(
+        &buildinfo_path,
+        &crate::debian::control::write_paragraph(&buildinfo_doc),
+    )?;
+
+    // Register the .buildinfo in debian/files, like dpkg-genbuildinfo does,
+    // so the .changes distributes it.
+    files_list.add(crate::debian::FilesEntry::new(
+        &buildinfo_name,
+        control.section(),
+        control.priority(),
+    ));
+    ctx.write_file(&package_dir.join("debian/files"), &files_list.render())?;
+
+    // Hash the freshly written .buildinfo inside the context.
+    let buildinfo_hashes =
+        hashes_in_context(ctx, upload_dir, std::slice::from_ref(&buildinfo_name))?;
+    if let Some(h) = buildinfo_hashes.get(&buildinfo_name) {
+        checksums.insert_entry(
+            &buildinfo_name,
+            ChecksumEntry {
+                size: h.size,
+                md5: h.md5.clone(),
+                sha1: h.sha1.clone(),
+                sha256: h.sha256.clone(),
+            },
+        );
+    }
+
+    // ------------------------------------------------------------------
+    // .changes generation
+    // ------------------------------------------------------------------
+    let changes_name = format!("{}_{}_{}.changes", entry.source, sversion, opts.host_arch);
+    let changed_by = format!("{} <{}>", entry.maintainer_name, entry.maintainer_email);
+    let changes_doc = crate::build::changes::render_changes(&crate::build::changes::ChangesInput {
+        date: entry.date_raw.clone(),
+        source: source_display,
+        binaries,
+        built_for_profiles: opts.profiles.clone(),
+        architecture: arch_values.join(" "),
+        version: entry.version.full(),
+        distribution: entry.distribution.clone(),
+        urgency: entry.urgency.clone(),
+        maintainer: control.source.get("Maintainer").map(str::to_string),
+        changed_by: Some(changed_by),
+        descriptions,
+        closes: entry.closes.clone(),
+        changes_field: entry.changes_field.clone(),
+        checksums,
+        files_list,
+    });
+    let changes_path = upload_dir.join(&changes_name);
+    ctx.write_file(
+        &changes_path,
+        &crate::debian::control::write_paragraph(&changes_doc),
+    )?;
+
+    Ok((buildinfo_path, changes_path))
+}
+
+/// Environment exported to the build steps; recorded (filtered) in the
+/// `.buildinfo` `Environment` field.
+fn pipeline_environment(opts: &BinaryMetadataOptions) -> BTreeMap<String, String> {
+    let mut env = BTreeMap::new();
+    env.insert(
+        "SOURCE_DATE_EPOCH".to_string(),
+        opts.source_date_epoch.to_string(),
+    );
+    env.insert(
+        "DEB_BUILD_OPTIONS".to_string(),
+        format!("parallel={}", opts.parallel),
+    );
+    if !opts.profiles.is_empty() {
+        env.insert("DEB_BUILD_PROFILES".to_string(), opts.profiles.join(","));
+    }
+    env
+}
+
+/// Compute md5/sha1/sha256 digests and sizes for the named files inside the
+/// context directory `dir`, using coreutils.
+fn hashes_in_context(
+    ctx: &Arc<Context>,
+    dir: &Path,
+    names: &[String],
+) -> Result<BTreeMap<String, ArtifactHashes>, Box<dyn Error>> {
+    let mut out: BTreeMap<String, ArtifactHashes> = names
+        .iter()
+        .map(|n| (n.clone(), ArtifactHashes::default()))
+        .collect();
+
+    // Sizes.
+    let output = ctx
+        .command("stat")
+        .current_dir(dir)
+        .arg("-c")
+        .arg("%s %n")
+        .args(names)
+        .output()?;
+    let stdout = String::from_utf8_lossy(&output.stdout);
+    for line in stdout.lines() {
+        let Some((size, name)) = line.trim().split_once(' ') else {
+            continue;
+        };
+        if let Some(slot) = out.get_mut(name) {
+            slot.size = size.parse().unwrap_or(0);
+        }
+    }
+
+    // Digests.
+    for (tool, field) in [
+        ("md5sum", 0usize),
+        ("sha1sum", 1usize),
+        ("sha256sum", 2usize),
+    ] {
+        let output = ctx
+            .command(tool)
+            .current_dir(dir)
+            .args(names)
+            .output()
+            .map_err(|e| format!("failed to run '{tool}' inside the build context: {e}"))?;
+        if !output.status.success() {
+            return Err(format!(
+                "'{tool}' failed inside the build context: {}",
+                String::from_utf8_lossy(&output.stderr).trim()
+            )
+            .into());
+        }
+        let stdout = String::from_utf8_lossy(&output.stdout);
+        for line in stdout.lines() {
+            let Some((digest, name)) = line.trim().split_once("  ") else {
+                continue;
+            };
+            let name = name.trim_start_matches('*');
+            if let Some(slot) = out.get_mut(name) {
+                match field {
+                    0 => slot.md5 = digest.to_string(),
+                    1 => slot.sha1 = digest.to_string(),
+                    _ => slot.sha256 = digest.to_string(),
+                }
+            }
+        }
+    }
+
+    Ok(out)
+}
+
+/// Pull the `.dsc` checksums (and its referenced tarballs) into the
+/// checksum registry, mirroring how binary-NMU uploads redistribute the
+/// previous source.
+fn include_dsc_artifacts(
+    ctx: &Arc<Context>,
+    upload_dir: &Path,
+    dsc_name: &str,
+    checksums: &mut FileChecksums,
+) -> Result<(), Box<dyn Error>> {
+    let dsc_content = ctx.read_file(&upload_dir.join(dsc_name))?;
+    let para = crate::debian::control::parse_paragraphs(&dsc_content)
+        .into_iter()
+        .next()
+        .ok_or_else(|| format!("'{dsc_name}' is empty"))?;
+
+    let mut names: Vec<String> = Vec::new();
+    let mut partials: BTreeMap<String, PartialDscChecksums> = BTreeMap::new();
+    for field in ["Checksums-Sha1", "Checksums-Sha256"] {
+        if let Some(value) = para.get(field) {
+            for line in value.lines() {
+                let tokens: Vec<&str> = line.split_whitespace().collect();
+                if tokens.len() != 3 {
+                    continue;
+                }
+                let slot = partials.entry(tokens[2].to_string()).or_default();
+                if field == "Checksums-Sha1" {
+                    slot.sha1 = Some(tokens[0].to_string());
+                } else {
+                    slot.sha256 = Some(tokens[0].to_string());
+                }
+                slot.size = tokens[1].parse().ok().or(slot.size);
+            }
+        }
+    }
+    if let Some(files_value) = para.get("Files") {
+        for line in files_value.lines() {
+            let tokens: Vec<&str> = line.split_whitespace().collect();
+            if tokens.len() >= 3 {
+                let slot = partials.entry(tokens[2].to_string()).or_default();
+                slot.md5 = Some(tokens[0].to_string());
+                slot.size = tokens[1].parse().ok().or(slot.size);
+            }
+        }
+    }
+    for field in ["Checksums-Sha1", "Checksums-Sha256"] {
+        if let Some(value) = para.get(field) {
+            for line in value.lines() {
+                if let Some(name) = line.split_whitespace().nth(2) {
+                    names.push(name.to_string());
+                }
+            }
+        }
+    }
+
+    // The .dsc itself is hashed fresh (it may be signed/rewritten); the
+    // tarballs reuse the .dsc-recorded digests, like dpkg-genchanges does.
+    let dsc_hashes =
+        hashes_in_context(ctx, upload_dir, std::slice::from_ref(&dsc_name.to_string()))?;
+    if let Some(h) = dsc_hashes.get(dsc_name) {
+        checksums.insert_entry(
+            dsc_name,
+            ChecksumEntry {
+                size: h.size,
+                md5: h.md5.clone(),
+                sha1: h.sha1.clone(),
+                sha256: h.sha256.clone(),
+            },
+        );
+    }
+    for name in &names {
+        if name == dsc_name {
+            continue;
+        }
+        let p = &partials[name];
+        checksums.insert_entry(
+            name,
+            ChecksumEntry {
+                size: p.size.unwrap_or(0),
+                md5: p.md5.clone().unwrap_or_default(),
+                sha1: p.sha1.clone().unwrap_or_default(),
+                sha256: p.sha256.clone().unwrap_or_default(),
+            },
+        );
+    }
+    Ok(())
+}
+
+/// Partially-known checksums taken from a `.dsc` checksum field.
+#[derive(Debug, Default)]
+struct PartialDscChecksums {
+    size: Option<u64>,
+    md5: Option<String>,
+    sha1: Option<String>,
+    sha256: Option<String>,
+}

src/build/buildinfo.rs

@@ -28,13 +28,6 @@ struct StatusDb {
 }
 
 impl StatusDb {
-    /// Parse a dpkg status file (e.g. `/var/lib/dpkg/status`).
-    fn load(path: &Path) -> Result<StatusDb, Box<dyn std::error::Error>> {
-        let content = std::fs::read_to_string(path)
-            .map_err(|e| format!("cannot read status file '{}': {}", path.display(), e))?;
-        Ok(Self::from_str(&content))
-    }
-
     fn from_str(content: &str) -> StatusDb {
         let mut db = StatusDb::default();
         for para in parse_paragraphs(content) {
@@ -132,7 +125,19 @@ pub fn installed_build_depends(
     status_path: &Path,
     build_depends_fields: &[&str],
 ) -> Result<String, Box<dyn std::error::Error>> {
-    let db = StatusDb::load(status_path)?;
+    let content = std::fs::read_to_string(status_path)
+        .map_err(|e| format!("cannot read status file '{}': {}", status_path.display(), e))?;
+    installed_build_depends_from_content(&content, build_depends_fields).map_err(|e| e.into())
+}
+
+/// Compute the `Installed-Build-Depends` value from the textual content of a
+/// dpkg status database (used when the database lives in another context,
+/// e.g. inside a chroot).
+pub fn installed_build_depends_from_content(
+    status_content: &str,
+    build_depends_fields: &[&str],
+) -> Result<String, String> {
+    let db = StatusDb::from_str(status_content);
 
     let mut work: VecDeque<String> = VecDeque::new();
     for name in &db.essential {

src/build/env.rs

@@ -1,10 +1,9 @@
 //! Build environment setup: `SOURCE_DATE_EPOCH`, `DEB_BUILD_OPTIONS`,
-//! architecture variables (via `dpkg-architecture`) and the sanitized
-//! environment recorded in `.buildinfo` files.
+//! architecture variables (native `dpkg-architecture` equivalent) and the
+//! sanitized environment recorded in `.buildinfo` files.
 
 use std::collections::BTreeMap;
 use std::path::Path;
-use std::process::Command;
 
 /// Number of parallel jobs to advertise in `DEB_BUILD_OPTIONS`.
 pub fn num_parallel() -> usize {
@@ -41,41 +40,15 @@ pub fn build_env(
     env
 }
 
-/// Import the full architecture variable set by running
-/// `dpkg-architecture -f [-a <host-arch>]` and parsing its `KEY=VALUE` dump.
+/// Import the full architecture variable set, computed natively by
+/// [`crate::debian::arch`] (the equivalent of `dpkg-architecture -f
+/// [-a <host-arch>]`).
 ///
 /// This exports all `DEB_BUILD_*`, `DEB_HOST_*` and `DEB_TARGET_*` variables
 /// (`*_ARCH`, `*_OS`, `*_CPU`, `*_MULTIARCH`, `*_GNU_TYPE`, ...), exactly as
 /// `dpkg-buildpackage` does.
 pub fn arch_env(host_arch: Option<&str>) -> Result<BTreeMap<String, String>, String> {
-    let mut cmd = Command::new("dpkg-architecture");
-    cmd.arg("-f");
-    if let Some(arch) = host_arch {
-        cmd.args(["--host-arch", arch]);
-    }
-
-    let output = cmd.output().map_err(|e| {
-        format!(
-            "failed to run 'dpkg-architecture': {}. Is 'dpkg-dev' installed?",
-            e
-        )
-    })?;
-
-    if !output.status.success() {
-        return Err(format!(
-            "dpkg-architecture failed with status {}: {}",
-            output.status,
-            String::from_utf8_lossy(&output.stderr).trim()
-        ));
-    }
-
-    let mut env = BTreeMap::new();
-    for line in String::from_utf8_lossy(&output.stdout).lines() {
-        if let Some((key, value)) = line.split_once('=') {
-            env.insert(key.to_string(), value.to_string());
-        }
-    }
-    Ok(env)
+    crate::debian::arch::arch_env(host_arch)
 }
 
 /// Read the current vendor name from `/etc/dpkg/origins/default`

src/build/mod.rs

@@ -6,6 +6,7 @@
 //! source-tree work (tarballs, diffs, patches) to `dpkg-source` as a
 //! subprocess.
 
+pub mod binary;
 pub mod buildinfo;
 pub mod buildtype;
 pub mod changes;
@@ -28,6 +29,10 @@ pub struct SourceBuildOptions {
     pub sign_keyid: Option<String>,
     /// Sign even for an UNRELEASED changelog (`--force-sign`).
     pub force_sign: bool,
+    /// Force build-dependency checking even though this is a source-only
+    /// build (`-D`). `dpkg-buildpackage` skips `dpkg-checkbuilddeps`
+    /// entirely for source-only builds unless forced.
+    pub force_dep_check: bool,
 }
 
 /// Artifacts produced by a successful source build.
@@ -198,6 +203,28 @@ pub fn run_source_build(
         &["-I", "-i", "--before-build", "."],
         &pipeline_env,
     )?;
+
+    // Build-dependency check (native dpkg-checkbuilddeps equivalent).
+    // dpkg-buildpackage skips it entirely for source-only builds unless
+    // forced with -D; unsatisfied dependencies abort with exit status 3.
+    if opts.force_dep_check {
+        let check_opts = crate::debian::deps::CheckOpts {
+            host_arch: arch_vars
+                .get("DEB_HOST_ARCH")
+                .cloned()
+                .unwrap_or_else(|| crate::debian::arch::native().unwrap_or_default()),
+            build_profiles: profiles.clone(),
+            ..Default::default()
+        };
+        let report = crate::debian::deps::check_build_depends(&ctrl, &check_opts)?;
+        if !report.is_ok() {
+            eprintln!("{}", report.message());
+            return Err(Box::new(crate::debian::deps::UnmetBuildDependencies(
+                report,
+            )));
+        }
+    }
+
     run_command(cwd, "dpkg-source", &["-I", "-i", "-b", "."], &pipeline_env)?;
 
     if !dsc_path.exists() {
@@ -747,7 +774,7 @@ mod differential_tests {
             if matches!(key, "Checksums-Sha1" | "Checksums-Sha256" | "Files") {
                 let without_buildinfo = |v: &str| -> String {
                     v.lines()
-                        .filter(|l| !l.trim_end().ends_with("_source.buildinfo"))
+                        .filter(|l| !l.trim_end().ends_with(".buildinfo"))
                         .collect::<Vec<_>>()
                         .join("\n")
                 };
@@ -859,6 +886,371 @@ mod differential_tests {
         differential_on_tree(&tree);
     }
 
+    /// Differential check of [`crate::debian::arch::arch_env`] against real
+    /// `dpkg-architecture -f -a <arch>` for one architecture.
+    fn diff_arch_env_one(arch: Option<&str>) {
+        let mut cmd = Command::new("dpkg-architecture");
+        cmd.arg("-f");
+        if let Some(a) = arch {
+            cmd.args(["-a", a]);
+        }
+        let output = cmd
+            .output()
+            .expect("run dpkg-architecture (is dpkg-dev installed?)");
+        assert!(
+            output.status.success(),
+            "dpkg-architecture -f {arch:?} failed: {}",
+            String::from_utf8_lossy(&output.stderr)
+        );
+        let mut expected = BTreeMap::new();
+        for line in String::from_utf8_lossy(&output.stdout).lines() {
+            if let Some((key, value)) = line.split_once('=') {
+                expected.insert(key.to_string(), value.to_string());
+            }
+        }
+
+        let ours = crate::debian::arch::arch_env(arch)
+            .unwrap_or_else(|e| panic!("native arch_env({arch:?}) failed: {e}"));
+        assert_eq!(
+            ours, expected,
+            "arch_env({arch:?}) differs from dpkg-architecture"
+        );
+    }
+
+    /// Every architecture known to the local dpkg must produce an identical
+    /// environment dump (`dpkg-architecture -L`).
+    #[test]
+    fn diff_arch_env_all_known_arches() {
+        let output = Command::new("dpkg-architecture")
+            .arg("-L")
+            .output()
+            .expect("run dpkg-architecture -L (is dpkg-dev installed?)");
+        assert!(output.status.success());
+        for arch in String::from_utf8_lossy(&output.stdout).lines() {
+            let arch = arch.trim();
+            if arch.is_empty() {
+                continue;
+            }
+            diff_arch_env_one(Some(arch));
+        }
+    }
+
+    /// Native (no explicit host architecture) must match too.
+    #[test]
+    fn diff_arch_env_native() {
+        diff_arch_env_one(None);
+    }
+
+    /// Differential check of [`crate::debian::deps::check_build_depends`]
+    /// against real `dpkg-checkbuilddeps` on one fixture: exit status and
+    /// reported unmet/conflict lists must match.
+    fn diff_checkbuilddeps_case(control: &str, status: &str, args: &[&str]) {
+        let dir = tempfile::tempdir().expect("tempdir");
+        std::fs::write(dir.path().join("control"), control).expect("write control");
+        let admindir = dir.path().join("admin");
+        fs::create_dir_all(&admindir).expect("mkdir admindir");
+        fs::write(admindir.join("status"), status).expect("write status");
+
+        // Real tool. Profiles are always pinned via -P so the comparison is
+        // independent of the local vendor defaults; -I skips the vendor
+        // builtin dependencies (build-essential:native), matching the
+        // native checker which knows no builtins. All options must precede
+        // the control-file operand (POSIX-style option parsing).
+        let output = Command::new("dpkg-checkbuilddeps")
+            .current_dir(dir.path())
+            .arg("--admindir")
+            .arg(&admindir)
+            .args(args)
+            .arg("-I")
+            .arg("control")
+            .output()
+            .expect("run dpkg-checkbuilddeps (is dpkg-dev installed?)");
+        let real_exit = output.status.code().unwrap_or(-1);
+        let real_msg = String::from_utf8_lossy(&output.stderr)
+            .lines()
+            .filter_map(|l| l.split_once("error: ").map(|(_, m)| m.trim()))
+            .collect::<Vec<_>>()
+            .join("\n");
+
+        // Native checker with equivalent options.
+        let mut profiles: Vec<String> = Vec::new();
+        let mut ignore_arch = false;
+        let mut ignore_indep = false;
+        let mut i = 0;
+        while i < args.len() {
+            match args[i] {
+                "-A" => ignore_arch = true,
+                "-B" => ignore_indep = true,
+                "-P" => {
+                    i += 1;
+                    profiles = args
+                        .get(i)
+                        .map(|p| p.split(',').map(str::to_string).collect())
+                        .unwrap_or_default();
+                }
+                _ => {}
+            }
+            i += 1;
+        }
+        let opts = crate::debian::deps::CheckOpts {
+            host_arch: crate::debian::arch::native().unwrap_or_else(|_| "amd64".into()),
+            build_profiles: profiles,
+            ignore_arch,
+            ignore_indep,
+            ignore_builtin: true,
+            admindir: admindir.clone(),
+        };
+        let control_info =
+            crate::debian::ControlInfo::parse_content(control).expect("parse control");
+        let report = crate::debian::deps::check_build_depends(&control_info, &opts)
+            .expect("native parse failure");
+
+        let ours_exit = if report.is_ok() { 0 } else { 1 };
+        assert_eq!(
+            ours_exit, real_exit,
+            "exit status mismatch for {control:?} {args:?}"
+        );
+        assert_eq!(
+            report.message(),
+            real_msg,
+            "diagnostics mismatch for {control:?} {args:?}"
+        );
+    }
+
+    /// Matrix of dependency-checking scenarios validated against the real
+    /// tool: alternatives, version relations, arch/profile restrictions,
+    /// conflicts and `-A`/`-B`/`-P` flag handling.
+    #[test]
+    fn diff_checkbuilddeps_matrix() {
+        const STATUS: &str = "\
+Package: libc6
+Status: install ok installed
+Version: 2.39-0ubuntu8
+Architecture: amd64
+
+Package: libfoo-dev
+Status: install ok installed
+Version: 1.2-3
+Architecture: amd64
+
+Package: ma-foreign-pkg
+Status: install ok installed
+Version: 1.0
+Architecture: i386
+Multi-Arch: foreign
+
+Package: provider
+Status: install ok installed
+Version: 5.0
+Architecture: amd64
+Provides: virtual-thing (= 2.0), plain-virtual
+";
+        const HEAD: &str = "Source: t\nMaintainer: a <a@b.c>\n";
+        const TAIL: &str = "\nPackage: t\nArchitecture: any\nDescription: x\n y\n";
+
+        let case = |bd: &str, bc: &str, args: &[&str]| {
+            let mut control = String::from(HEAD);
+            if !bd.is_empty() {
+                control.push_str(&format!("Build-Depends: {bd}\n"));
+            }
+            if !bc.is_empty() {
+                control.push_str(&format!("Build-Conflicts: {bc}\n"));
+            }
+            control.push_str(TAIL);
+            diff_checkbuilddeps_case(&control, STATUS, args);
+        };
+
+        // Satisfied / unsatisfied basics.
+        case("libc6 (>= 1)", "", &["-P", "cross"]);
+        case("missing-abc", "", &["-P", "cross"]);
+        case("libc6 (>> 999)", "", &["-P", "cross"]);
+        // Alternatives.
+        case("missing-a | libc6", "", &["-P", "cross"]);
+        case("missing-a | missing-b", "", &["-P", "cross"]);
+        // Architecture restrictions (host is the native arch).
+        case("missing-abc [!amd64]", "", &["-P", "cross"]);
+        case("missing-abc [amd64]", "", &["-P", "cross"]);
+        // Profile restrictions.
+        case("missing-abc <stage1>", "", &["-P", "stage1"]);
+        case("missing-abc <stage1>", "", &["-P", "cross"]);
+        case("missing-abc <!stage1>", "", &["-P", "stage1"]);
+        // Multi-Arch foreign satisfies unqualified deps.
+        case("ma-foreign-pkg", "", &["-P", "cross"]);
+        // Provides: versioned provide satisfying / not satisfying.
+        case("virtual-thing (>= 1.0)", "", &["-P", "cross"]);
+        case("virtual-thing (>= 3.0)", "", &["-P", "cross"]);
+        case("plain-virtual", "", &["-P", "cross"]);
+        case("plain-virtual (>= 1.0)", "", &["-P", "cross"]);
+        // Conflicts.
+        case("", "libc6 (<< 1)", &["-P", "cross"]);
+        case("", "libc6", &["-P", "cross"]);
+        case("", "missing-abc", &["-P", "cross"]);
+        // -A/-B field handling.
+        let control_ab = format!(
+            "{HEAD}Build-Depends: libc6\nBuild-Depends-Arch: missing-arch-dep\nBuild-Depends-Indep: missing-indep-dep\n{TAIL}"
+        );
+        diff_checkbuilddeps_case(&control_ab, STATUS, &["-P", "cross"]);
+        diff_checkbuilddeps_case(&control_ab, STATUS, &["-A", "-P", "cross"]);
+        diff_checkbuilddeps_case(&control_ab, STATUS, &["-B", "-P", "cross"]);
+
+        // Combined unmet + conflict reporting in one run.
+        case(
+            "missing-one, libc6 (>> 999)",
+            "libfoo-dev",
+            &["-P", "cross"],
+        );
+    }
+
+    /// Differential check of [`crate::debian::version`] against real
+    /// `dpkg --compare-versions` over every ported dpkg test vector and
+    /// every relation operator.
+    #[test]
+    fn diff_version_compare_against_dpkg() {
+        let vectors = crate::debian::version::test_vectors::COMPARE;
+        assert!(!vectors.is_empty());
+        for (a, b, expected) in vectors {
+            let va =
+                crate::debian::DebianVersion::parse(a).unwrap_or_else(|e| panic!("parse {a}: {e}"));
+            let vb =
+                crate::debian::DebianVersion::parse(b).unwrap_or_else(|e| panic!("parse {b}: {e}"));
+            let ours = match va.cmp(&vb) {
+                std::cmp::Ordering::Less => -1,
+                std::cmp::Ordering::Equal => 0,
+                std::cmp::Ordering::Greater => 1,
+            };
+            assert_eq!(ours, *expected, "native compare: {a} cmp {b}");
+
+            // Cross-check the relation operators against the real tool.
+            for (op, holds) in [
+                ("<<", *expected < 0),
+                ("<=", *expected <= 0),
+                ("=", *expected == 0),
+                (">=", *expected >= 0),
+                (">>", *expected > 0),
+            ] {
+                let output = Command::new("dpkg")
+                    .args(["--compare-versions", "--", a, op, b])
+                    .status()
+                    .expect("run dpkg --compare-versions");
+                assert_eq!(
+                    output.success(),
+                    holds,
+                    "dpkg --compare-versions -- {a} {op} {b}"
+                );
+            }
+        }
+    }
+
+    /// Differential check of the binary-build metadata generation against
+    /// real `dpkg-buildpackage -b`: both sides build the same tree (rules
+    /// driving dpkg-gencontrol/dpkg-deb directly, no debhelper needed),
+    /// then the produced `.changes`/`.buildinfo` are compared field by
+    /// field modulo machine-dependent values.
+    #[test]
+    fn diff_binary_build_metadata() {
+        const NAME: &str = "pkh-diff-m";
+        let control = format!(
+            "Source: {NAME}\nSection: utils\nPriority: optional\nMaintainer: {MAINTAINER}\nBuild-Depends: libc6\n\n\
+             Package: {NAME}\nArchitecture: any\nDescription: test package main\n long description\n\n\
+             Package: {NAME}-u\nPackage-Type: udeb\nArchitecture: all\nDescription: test udeb\n short\n"
+        );
+        let changelog = format!(
+            "{NAME} (1.0-1) unstable; urgency=medium\n\n  * Binary build test.\n\n -- {MAINTAINER}  {DATE}\n"
+        );
+        let rules = format!(
+            "#!/usr/bin/make -f\nV = $(shell dpkg-parsechangelog -S Version)\nA = $(shell dpkg-architecture -qDEB_HOST_ARCH)\n\nbuild:\n\tmkdir -p debian/tmp/usr/bin\n\tprintf '#!/bin/sh\\necho hi\\n' > debian/tmp/usr/bin/hello\n\tchmod 755 debian/tmp/usr/bin/hello\n\ttouch $@\n\nbinary: build\n\trm -rf debian/{NAME} debian/{NAME}-u\n\tmkdir -p debian/{NAME}/usr/bin debian/{NAME}/DEBIAN\n\tcp -r debian/tmp/. debian/{NAME}/\n\tdpkg-gencontrol -p{NAME} -Pdebian/{NAME}\n\tdpkg-deb --build debian/{NAME} ..\n\tmkdir -p debian/{NAME}-u/usr/share debian/{NAME}-u/DEBIAN\n\techo data > debian/{NAME}-u/usr/share/data.txt\n\tdpkg-gencontrol -p{NAME}-u -Pdebian/{NAME}-u\n\tdpkg-deb --build debian/{NAME}-u ..\n\tmv ../{NAME}-u_$(V)_all.deb ../{NAME}-u_$(V)_all.udeb\n\nclean:\n\trm -rf debian/tmp debian/{NAME} debian/{NAME}-u build-stamp debian/files debian/*.substvars\n\n.PHONY: build binary clean\n"
+        );
+
+        let write_tree = |root: &Path| {
+            fs::create_dir_all(root.join(format!("{NAME}/debian/source"))).expect("mkdir tree");
+            let tree = root.join(NAME);
+            fs::write(tree.join("debian/control"), &control).expect("write control");
+            fs::write(tree.join("debian/changelog"), &changelog).expect("write changelog");
+            fs::write(tree.join("debian/source/format"), "3.0 (native)\n").expect("write format");
+            fs::write(tree.join("debian/rules"), &rules).expect("write rules");
+            #[cfg(unix)]
+            {
+                use std::os::unix::fs::PermissionsExt;
+                fs::set_permissions(tree.join("debian/rules"), fs::Permissions::from_mode(0o755))
+                    .expect("chmod rules");
+            }
+            tree
+        };
+
+        let base = tempfile::tempdir().expect("tempdir");
+        let golden_root = base.path().join("golden");
+        let ours_root = base.path().join("ours");
+        fs::create_dir_all(&golden_root).expect("mkdir golden");
+        fs::create_dir_all(&ours_root).expect("mkdir ours");
+
+        let golden_tree = write_tree(&golden_root);
+        let ours_tree = write_tree(&ours_root);
+
+        // Golden side: real dpkg-buildpackage binary build.
+        let status = Command::new("dpkg-buildpackage")
+            .current_dir(&golden_tree)
+            .args(["-b", "-d", "--no-sign"])
+            .status()
+            .expect("run dpkg-buildpackage (is dpkg-dev installed?)");
+        assert!(status.success(), "golden dpkg-buildpackage -b failed");
+
+        // Ours: emulate the pkh deb flow (rules build + rules binary with a
+        // dpkg-buildpackage-like environment), then run the native metadata
+        // generation through a local context. dpkg-buildpackage runs the
+        // rules targets directly by default (missing Rules-Requires-Root is
+        // treated as 'no'), so no fakeroot wrapper here either.
+        let entry =
+            crate::debian::parse_changelog_entry_from_str(&changelog).expect("parse changelog");
+        let vendor = env::current_vendor();
+        let profiles = env::resolve_build_profiles(&[], &vendor);
+        let parallel = env::num_parallel();
+        let build_env_vars: Vec<(String, String)> = [
+            ("LANG".to_string(), "C".to_string()),
+            (
+                "DEB_BUILD_OPTIONS".to_string(),
+                format!("parallel={parallel}"),
+            ),
+            ("SOURCE_DATE_EPOCH".to_string(), entry.timestamp.to_string()),
+        ]
+        .into_iter()
+        .collect();
+
+        for target in ["build", "binary"] {
+            let status = Command::new("debian/rules")
+                .current_dir(&ours_tree)
+                .envs(build_env_vars.clone())
+                .arg(target)
+                .status()
+                .expect("run rules target");
+            assert!(status.success(), "debian/rules {target} failed");
+        }
+
+        let ctx = std::sync::Arc::new(crate::context::Context::new(
+            crate::context::ContextConfig::Local,
+        ));
+        let native_arch = crate::debian::arch::native().unwrap_or_else(|_| "amd64".into());
+        let opts = crate::build::binary::BinaryMetadataOptions {
+            profiles,
+            vendor,
+            parallel,
+            source_date_epoch: entry.timestamp,
+            build_arch: native_arch.clone(),
+            host_arch: native_arch,
+        };
+        crate::build::binary::generate_binary_metadata(&ctx, &ours_tree, &ours_root, &opts)
+            .expect("native binary metadata generation failed");
+
+        // Compare artifacts.
+        assert_changes_equivalent(
+            &golden_root.join(format!("{NAME}_1.0-1_amd64.changes")),
+            &ours_root.join(format!("{NAME}_1.0-1_amd64.changes")),
+        );
+        assert_buildinfo_equivalent(
+            &golden_root.join(format!("{NAME}_1.0-1_amd64.buildinfo")),
+            &ours_root.join(format!("{NAME}_1.0-1_amd64.buildinfo")),
+        );
+    }
+
     #[test]
     fn diff_native_minimal() {
         differential_case(&FixtureSpec::new("pkh-diff-a", "1.0-1", "unstable"));

src/deb/local.rs

@@ -227,6 +227,17 @@ pub async fn build(
         .to_str()
         .ok_or("Invalid package directory path")?;
 
+    // Reproducibility: export SOURCE_DATE_EPOCH from the changelog entry,
+    // like dpkg-buildpackage does.
+    match ctx.read_file(&package_dir.join("debian/changelog")) {
+        Ok(content) => {
+            if let Ok(entry) = crate::debian::parse_changelog_entry_from_str(&content) {
+                env.insert("SOURCE_DATE_EPOCH".to_string(), entry.timestamp.to_string());
+            }
+        }
+        Err(e) => log::debug!("cannot read changelog for SOURCE_DATE_EPOCH: {}", e),
+    }
+
     // Apply quilt patches if the package provides a patch series
     apply_quilt_patches(package_dir_str, &env, ctx.clone(), &ui, &sink)?;
 
@@ -318,6 +329,91 @@ pub async fn build(
         );
     }
 
+    // Generate the upload metadata (.buildinfo + .changes) natively, the
+    // equivalent of dpkg-genbuildinfo -b + dpkg-genchanges -b, consuming
+    // debian/files produced by the build. Failures are logged but do not
+    // discard the produced binaries.
+    if let Err(e) = generate_upload_metadata(package_dir_str, build_root, arch, cross, &env, &ctx) {
+        warn!("failed to generate .buildinfo/.changes: {}", e);
+    }
+
+    Ok(())
+}
+
+/// Generate `.buildinfo` and `.changes` for the finished binary build,
+/// inside the build context.
+fn generate_upload_metadata(
+    package_dir: &str,
+    build_root: &str,
+    arch: &str,
+    cross: bool,
+    env: &HashMap<String, String>,
+    ctx: &Arc<Context>,
+) -> Result<(), Box<dyn Error>> {
+    use std::path::Path;
+
+    let changelog_path = Path::new(package_dir).join("debian/changelog");
+    let changelog_content = ctx.read_file(&changelog_path)?;
+    let entry = crate::debian::parse_changelog_entry_from_str(&changelog_content)?;
+
+    // Build architecture: the machine inside the build context.
+    let build_arch = ctx
+        .command("dpkg")
+        .arg("--print-architecture")
+        .output()
+        .ok()
+        .filter(|o| o.status.success())
+        .map(|o| String::from_utf8_lossy(&o.stdout).trim().to_string())
+        .filter(|s| !s.is_empty())
+        .unwrap_or_else(crate::get_current_arch);
+    let host_arch = if cross {
+        arch.to_string()
+    } else {
+        build_arch.clone()
+    };
+
+    // Vendor resolution inside the context (falls back to the host view).
+    let vendor = ctx
+        .read_file(Path::new("/etc/dpkg/origins/default"))
+        .ok()
+        .and_then(|content| {
+            for line in content.lines() {
+                if let Some(v) = line.strip_prefix("Vendor:") {
+                    let v = v.trim();
+                    if !v.is_empty() {
+                        return Some(v.to_string());
+                    }
+                }
+            }
+            None
+        })
+        .unwrap_or_else(crate::build::env::current_vendor);
+
+    let profiles = crate::build::env::resolve_build_profiles(&[], &vendor);
+    let source_date_epoch = env
+        .get("SOURCE_DATE_EPOCH")
+        .and_then(|v| v.parse::<i64>().ok())
+        .unwrap_or(entry.timestamp);
+
+    let opts = crate::build::binary::BinaryMetadataOptions {
+        profiles,
+        vendor,
+        parallel: crate::build::env::num_parallel(),
+        source_date_epoch,
+        build_arch,
+        host_arch,
+    };
+    let (buildinfo, changes) = crate::build::binary::generate_binary_metadata(
+        ctx,
+        Path::new(package_dir),
+        Path::new(build_root),
+        &opts,
+    )?;
+    log::info!(
+        "generated upload metadata: {} and {}",
+        buildinfo.display(),
+        changes.display()
+    );
     Ok(())
 }
 

src/deb/mod.rs

@@ -165,14 +165,22 @@ async fn build_binary_package_impl(
             }
         }
 
-        // Retrieve produced .deb files
+        // Retrieve produced artifacts (.deb files plus the upload metadata
+        // (.buildinfo/.changes) generated natively after the build)
         if let Some(u) = ui {
             u.phase(Phase::RetrievingArtifacts);
         }
         let remote_files = build_ctx.list_files(Path::new(&build_root))?;
         let deb_files: Vec<PathBuf> = remote_files
             .into_iter()
-            .filter(|f| f.extension().is_some_and(|ext| ext == "deb"))
+            .filter(|f| {
+                f.extension().is_some_and(|ext| {
+                    matches!(
+                        ext.to_str(),
+                        Some("deb") | Some("buildinfo") | Some("changes")
+                    )
+                })
+            })
             .collect();
         let total_debs = deb_files.len();
 

src/debian/changelog.rs

@@ -46,7 +46,15 @@ pub fn parse_changelog_entry(path: &Path) -> Result<ChangelogEntry, Box<dyn std:
             e
         )
     })?;
+    parse_changelog_entry_from_str(&content)
+}
 
+/// Parse the most recent changelog entry from its textual content. `origin`
+/// is used in error messages only.
+pub fn parse_changelog_entry_from_str(
+    content: &str,
+) -> Result<ChangelogEntry, Box<dyn std::error::Error>> {
+    let origin = "changelog";
     let mut lines = content.lines().peekable();
 
     // --- Header line: `package (version) distributions; urgency=medium[, key=value]`
@@ -55,18 +63,14 @@ pub fn parse_changelog_entry(path: &Path) -> Result<ChangelogEntry, Box<dyn std:
             Some(l) if l.trim().is_empty() => continue,
             Some(l) => break l.trim_end(),
             None => {
-                return Err(format!("changelog '{}' is empty", path.display()).into());
+                return Err(format!("changelog '{origin}' is empty").into());
             }
         }
     };
 
-    let open = header.find('(').ok_or_else(|| {
-        format!(
-            "invalid changelog header in '{}': {}",
-            path.display(),
-            header
-        )
-    })?;
+    let open = header
+        .find('(')
+        .ok_or_else(|| format!("invalid changelog header in '{origin}': {header}"))?;
     let close = header[open..]
         .find(')')
         .ok_or_else(|| format!("unbalanced parenthesis in changelog header '{}'", header))?;
@@ -123,9 +127,8 @@ pub fn parse_changelog_entry(path: &Path) -> Result<ChangelogEntry, Box<dyn std:
 
     let trailer_line = trailer.ok_or_else(|| {
         format!(
-            "no maintainer trailer found in '{}': expected a line of the form \
-             ' -- Name <email>  Date'",
-            path.display()
+            "no maintainer trailer found in '{origin}': expected a line of the form \
+             ' -- Name <email>  Date'"
         )
     })?;
 
@@ -147,14 +150,7 @@ pub fn parse_changelog_entry(path: &Path) -> Result<ChangelogEntry, Box<dyn std:
     let date_raw = trailer_body[gt + 1..].trim().to_string();
 
     let timestamp = DateTime::parse_from_rfc2822(&date_raw)
-        .map_err(|e| {
-            format!(
-                "cannot parse changelog date '{}' in '{}': {}",
-                date_raw,
-                path.display(),
-                e
-            )
-        })?
+        .map_err(|e| format!("cannot parse changelog date '{date_raw}' in '{origin}': {e}"))?
         .timestamp();
 
     // Changes field value (leading `\n` marks it as a pre-wrapped multiline
@@ -220,7 +216,14 @@ fn find_closes(body_lines: &[String]) -> Option<String> {
 pub fn parse_previous_version(path: &Path) -> Result<Option<String>, Box<dyn std::error::Error>> {
     let content = std::fs::read_to_string(path)
         .map_err(|e| format!("failed to read changelog '{}': {}", path.display(), e))?;
+    parse_previous_version_from_str(&content)
+}
 
+/// Return the version of the *previous* changelog entry from the textual
+/// content of a changelog file.
+pub fn parse_previous_version_from_str(
+    content: &str,
+) -> Result<Option<String>, Box<dyn std::error::Error>> {
     let mut seen_first = false;
     for line in content.lines() {
         let line = line.trim_end();
@@ -229,12 +232,12 @@ pub fn parse_previous_version(path: &Path) -> Result<Option<String>, Box<dyn std
                 seen_first = true;
                 continue;
             }
-            let open = line.find('(').ok_or_else(|| {
-                format!("invalid changelog header in '{}': {}", path.display(), line)
-            })?;
+            let open = line
+                .find('(')
+                .ok_or_else(|| format!("invalid changelog header: {line}"))?;
             let close = line[open..]
                 .find(')')
-                .ok_or_else(|| format!("unbalanced parenthesis in changelog header '{}'", line))?;
+                .ok_or_else(|| format!("unbalanced parenthesis in changelog header '{line}'"))?;
             return Ok(Some(line[open + 1..open + close].to_string()));
         }
     }

src/debian/files.rs

@@ -114,29 +114,30 @@ impl FilesList {
 
     /// Load `debian/files`. A missing file yields an empty registry.
     pub fn load(path: &Path) -> Result<FilesList, Box<dyn std::error::Error>> {
-        let mut list = FilesList::new();
         let content = match std::fs::read_to_string(path) {
             Ok(c) => c,
-            Err(e) if e.kind() == std::io::ErrorKind::NotFound => return Ok(list),
+            Err(e) if e.kind() == std::io::ErrorKind::NotFound => return Ok(FilesList::new()),
             Err(e) => {
                 return Err(format!("cannot read '{}': {}", path.display(), e).into());
             }
         };
+        FilesList::parse(&content).map_err(|e| format!("in '{}': {}", path.display(), e).into())
+    }
+
+    /// Parse a `debian/files` registry from its textual content
+    /// (`filename section priority [key=value...]` lines).
+    pub fn parse(content: &str) -> Result<FilesList, String> {
+        let mut list = FilesList::new();
         for line in content.lines() {
             if line.trim().is_empty() {
                 continue;
             }
             let tokens: Vec<&str> = line.split_whitespace().collect();
             if tokens.len() < 3 {
-                return Err(format!("badly formed line in '{}': {}", path.display(), line).into());
+                return Err(format!("badly formed line: {line}"));
             }
-            let mut entry = parse_filename(tokens[0]).ok_or_else(|| {
-                format!(
-                    "badly formed file name in '{}': {}",
-                    path.display(),
-                    tokens[0]
-                )
-            })?;
+            let mut entry = parse_filename(tokens[0])
+                .ok_or_else(|| format!("badly formed file name: {}", tokens[0]))?;
             entry.section = tokens[1].to_string();
             entry.priority = tokens[2].to_string();
             for attr in &tokens[3..] {
@@ -181,6 +182,23 @@ impl FilesList {
         self.files.is_empty()
     }
 
+    /// Render the registry to its textual `debian/files` representation.
+    pub fn render(&self) -> String {
+        let mut out = String::new();
+        for entry in self.iter() {
+            out.push_str(&entry.filename);
+            out.push(' ');
+            out.push_str(&entry.section);
+            out.push(' ');
+            out.push_str(&entry.priority);
+            for (k, v) in &entry.attrs {
+                out.push_str(&format!(" {k}={v}"));
+            }
+            out.push('\n');
+        }
+        out
+    }
+
     /// Save atomically: write `<path>.new` then rename over `path`, like
     /// dpkg does.
     pub fn save_atomic(&self, path: &Path) -> Result<(), Box<dyn std::error::Error>> {

src/debian/mod.rs

@@ -3,19 +3,26 @@
 //! These components are independent from any build orchestration and can be
 //! used by any pkh submodule (or external consumers of the library):
 //!
+//! - [`arch`]: Debian architecture tables and lookups (dpkg-architecture)
 //! - [`control`]: deb822 paragraph parsing/writing and `debian/control`
 //! - [`checksums`]: file checksum registry (`Dpkg::Checksums` equivalent)
+//! - [`deps`]: dependency grammar and evaluation (dpkg-checkbuilddeps)
 //! - [`files`]: `debian/files` artifact registry (`Dpkg::Dist::Files`)
-//! - [`version`]: Debian version splitting/validation
+//! - [`version`]: Debian version splitting/validation/comparison
 //! - [`changelog`]: `debian/changelog` entry parsing
 
+pub mod arch;
 pub mod changelog;
 pub mod checksums;
 pub mod control;
+pub mod deps;
 pub mod files;
 pub mod version;
 
-pub use changelog::{ChangelogEntry, parse_changelog_entry};
+pub use changelog::{
+    ChangelogEntry, parse_changelog_entry, parse_changelog_entry_from_str,
+    parse_previous_version_from_str,
+};
 pub use checksums::{Entry as ChecksumEntry, FileChecksums};
 pub use control::{ControlInfo, Paragraph, parse_paragraphs, write_paragraph};
 pub use files::{FilesEntry, FilesList};

src/debian/version.rs

@@ -1,4 +1,4 @@
-//! Debian version handling: splitting and validation of
+//! Debian version handling: splitting, validation and ordering of
 //! `[epoch:]upstream[-revision]` version strings.
 
 /// A Debian version, split into its `[epoch:]upstream[-revision]` parts.
@@ -83,6 +83,217 @@ impl DebianVersion {
             None => self.upstream.clone(),
         }
     }
+
+    /// Convenience predicate: whether this version orders strictly later
+    /// than `other`.
+    pub fn later_than(&self, other: &DebianVersion) -> bool {
+        self > other
+    }
+}
+
+/// Compare two versions according to dpkg's ordering algorithm
+/// (Debian Policy §5.6.1 / `dpkg(1)`):
+///
+/// - the epoch compares numerically (a missing epoch counts as `0`),
+/// - then the upstream version and the Debian revision compare by
+///   alternating non-digit and digit chunks, from left to right,
+/// - in non-digit chunks letters sort earlier than non-letters, and `~`
+///   sorts before anything, including the end of the chunk,
+/// - digit chunks compare numerically (leading zeroes are irrelevant; an
+///   empty digit chunk counts as `0`, so a missing revision equals `0`).
+pub fn compare(a: &DebianVersion, b: &DebianVersion) -> std::cmp::Ordering {
+    a.epoch
+        .unwrap_or(0)
+        .cmp(&b.epoch.unwrap_or(0))
+        .then_with(|| verrevcmp(a.upstream.as_bytes(), b.upstream.as_bytes()))
+        .then_with(|| {
+            verrevcmp(
+                a.debian_revision.as_deref().unwrap_or("").as_bytes(),
+                b.debian_revision.as_deref().unwrap_or("").as_bytes(),
+            )
+        })
+}
+
+/// Sort weight of a character inside a non-digit chunk: `~` sorts before the
+/// end of the chunk, letters before non-letters, everything else by ASCII
+/// order.
+fn char_order(c: u8) -> i32 {
+    if c == b'~' {
+        -1
+    } else if c.is_ascii_alphabetic() {
+        i32::from(c)
+    } else {
+        i32::from(c) + 256
+    }
+}
+
+/// Compare the upstream/revision part of two versions by alternating
+/// non-digit and digit chunks.
+fn verrevcmp(mut a: &[u8], mut b: &[u8]) -> std::cmp::Ordering {
+    use std::cmp::Ordering;
+
+    while !a.is_empty() || !b.is_empty() {
+        let mut first_diff: i32 = 0;
+
+        // Non-digit chunks: compare by character weight. A chunk boundary
+        // (end of string or start of a digit run) weighs 0, which sorts
+        // after `~` (-1) and before every real character.
+        while (!a.is_empty() && !a[0].is_ascii_digit()) || (!b.is_empty() && !b[0].is_ascii_digit())
+        {
+            let ac = if !a.is_empty() && !a[0].is_ascii_digit() {
+                char_order(a[0])
+            } else {
+                0
+            };
+            let bc = if !b.is_empty() && !b[0].is_ascii_digit() {
+                char_order(b[0])
+            } else {
+                0
+            };
+            if ac != bc {
+                return ac.cmp(&bc);
+            }
+            // Reaching here means both sides carried equal real characters.
+            a = &a[1..];
+            b = &b[1..];
+        }
+
+        // Digit chunks: strip leading zeroes, then the number whose
+        // remaining digit run is longer is larger; otherwise the first
+        // differing digit decides.
+        while !a.is_empty() && a[0] == b'0' {
+            a = &a[1..];
+        }
+        while !b.is_empty() && b[0] == b'0' {
+            b = &b[1..];
+        }
+        while !a.is_empty() && !b.is_empty() && a[0].is_ascii_digit() && b[0].is_ascii_digit() {
+            if first_diff == 0 {
+                first_diff = i32::from(a[0]) - i32::from(b[0]);
+            }
+            a = &a[1..];
+            b = &b[1..];
+        }
+        if !a.is_empty() && a[0].is_ascii_digit() {
+            return Ordering::Greater;
+        }
+        if !b.is_empty() && b[0].is_ascii_digit() {
+            return Ordering::Less;
+        }
+        if first_diff != 0 {
+            return first_diff.cmp(&0);
+        }
+    }
+    Ordering::Equal
+}
+
+impl PartialOrd for DebianVersion {
+    fn partial_cmp(&self, other: &Self) -> Option<std::cmp::Ordering> {
+        Some(self.cmp(other))
+    }
+}
+
+impl Ord for DebianVersion {
+    fn cmp(&self, other: &Self) -> std::cmp::Ordering {
+        compare(self, other)
+    }
+}
+
+/// Test vectors ported from dpkg's `scripts/t/Dpkg_Version.t` (`__DATA__`
+/// section): `(version_a, version_b, expected_cmp)` with `-1/0/1`. Shared
+/// with the differential tests against real `dpkg --compare-versions`.
+#[cfg(test)]
+pub(crate) mod test_vectors {
+    /// `(a, b, cmp)` triples.
+    pub(crate) const COMPARE: &[(&str, &str, i32)] = &[
+        ("1.0-1", "2.0-2", -1),
+        ("2.2~rc-4", "2.2-1", -1),
+        ("2.2-1", "2.2~rc-4", 1),
+        ("1.0000-1", "1.0-1", 0),
+        ("1", "0:1", 0),
+        ("0", "0:0-0", 0),
+        ("2:2.5", "1:7.5", 1),
+        ("1:0foo", "0foo", 1),
+        ("0:0foo", "0foo", 0),
+        ("0foo", "0foo", 0),
+        ("0foo-0", "0foo", 0),
+        ("0foo", "0foo-0", 0),
+        ("0foo", "0fo", 1),
+        ("0foo-0", "0foo+", -1),
+        ("0foo~1", "0foo", -1),
+        ("0foo~foo+Bar", "0foo~foo+bar", -1),
+        ("0foo~~", "0foo~", -1),
+        ("1~", "1", -1),
+        (
+            "12345+that-really-is-some-ver-0",
+            "12345+that-really-is-some-ver-10",
+            -1,
+        ),
+        ("0foo-0", "0foo-01", -1),
+        ("0foo.bar", "0foobar", 1),
+        ("0foo.bar", "0foo1bar", 1),
+        ("0foo.bar", "0foo0bar", 1),
+        ("0foo1bar-1", "0foobar-1", -1),
+        ("0foo2.0", "0foo2", 1),
+        ("0foo2.0.0", "0foo2.10.0", -1),
+        ("0foo2.0", "0foo2.0.0", -1),
+        ("0foo2.0", "0foo2.10", -1),
+        ("0foo2.1", "0foo2.10", -1),
+        ("1.09", "1.9", 0),
+        ("1.0.8+nmu1", "1.0.8", 1),
+        ("3.11", "3.10+nmu1", 1),
+        ("0.9j-20080306-4", "0.9i-20070324-2", 1),
+        ("1.2.0~b7-1", "1.2.0~b6-1", 1),
+        ("1.011-1", "1.06-2", 1),
+        ("0.0.9+dfsg1-1", "0.0.8+dfsg1-3", 1),
+        ("4.6.99+svn6582-1", "4.6.99+svn6496-1", 1),
+        ("53", "52", 1),
+        ("0.9.9~pre122-1", "0.9.9~pre111-1", 1),
+        ("2:2.3.2-2+lenny2", "2:2.3.2-2", 1),
+        ("1:3.8.1-1", "3.8.GA-1", 1),
+        ("1.0.1+gpl-1", "1.0.1-2", 1),
+        ("1a", "1000a", -1),
+    ];
+
+    /// Unsorted lists with their expected order under dpkg comparison.
+    pub(crate) const SORTED: &[(&[&str], &[&str])] = &[
+        (
+            &[
+                "4:4-4",
+                "5.0abc",
+                "0.0-0.0alpha0",
+                "10.100.1-1",
+                "0~999.999zeta",
+                "0:1.0-0",
+            ],
+            &[
+                "0~999.999zeta",
+                "0.0-0.0alpha0",
+                "0:1.0-0",
+                "5.0abc",
+                "10.100.1-1",
+                "4:4-4",
+            ],
+        ),
+        (
+            &[
+                "4",
+                "5.0abc",
+                "0.0alpha0",
+                "10.100.1",
+                "0~999.999zeta",
+                "1.0",
+            ],
+            &[
+                "0~999.999zeta",
+                "0.0alpha0",
+                "1.0",
+                "4",
+                "5.0abc",
+                "10.100.1",
+            ],
+        ),
+    ];
 }
 
 #[cfg(test)]
@@ -117,4 +328,68 @@ mod tests {
         assert!(DebianVersion::parse("1.0").is_ok());
         assert!(DebianVersion::parse("1.0~rc1-2").is_ok());
     }
+
+    fn cmp_sign(a: &DebianVersion, b: &DebianVersion) -> i32 {
+        match a.cmp(b) {
+            std::cmp::Ordering::Less => -1,
+            std::cmp::Ordering::Equal => 0,
+            std::cmp::Ordering::Greater => 1,
+        }
+    }
+
+    /// All vectors from dpkg's own `Dpkg_Version.t` must pass.
+    #[test]
+    fn comparison_dpkg_vectors() {
+        for (a, b, expected) in test_vectors::COMPARE {
+            let va = DebianVersion::parse(a).unwrap_or_else(|e| panic!("parse {a}: {e}"));
+            let vb = DebianVersion::parse(b).unwrap_or_else(|e| panic!("parse {b}: {e}"));
+            assert_eq!(
+                cmp_sign(&va, &vb),
+                *expected,
+                "{a} cmp {b} must be {expected}"
+            );
+            // Ordering is antisymmetric.
+            assert_eq!(cmp_sign(&vb, &va), -*expected, "{b} cmp {a}");
+        }
+    }
+
+    #[test]
+    fn sorting_dpkg_vectors() {
+        for (unsorted, expected) in test_vectors::SORTED {
+            let mut versions: Vec<DebianVersion> = unsorted
+                .iter()
+                .map(|v| DebianVersion::parse(v).unwrap())
+                .collect();
+            versions.sort();
+            let rendered: Vec<String> = versions.iter().map(DebianVersion::full).collect();
+            let expected: Vec<String> = expected.iter().map(|s| s.to_string()).collect();
+            assert_eq!(rendered, expected);
+        }
+    }
+
+    /// Ubuntu-flavored cases: security updates, backports, PPA versions.
+    #[test]
+    fn comparison_ubuntu_flavored() {
+        let cases: &[(&str, &str, i32)] = &[
+            // Security update on top of a release upload.
+            ("1.0-0ubuntu1", "1.0-0ubuntu1.22.04.1", -1),
+            // PPA/backports pre-releases sort before the real upload.
+            ("1.0-0ubuntu1~ppa1", "1.0-0ubuntu1", -1),
+            ("1.0~bpo22.04.1", "1.0", -1),
+            // Series-specific uploads.
+            ("2.3-1ubuntu3.22.04.2", "2.3-1ubuntu3", 1),
+            ("1:2.0.4-0ubuntu1", "1:2.0.4-0ubuntu1.1", -1),
+        ];
+        for (a, b, expected) in cases {
+            let va = DebianVersion::parse(a).unwrap();
+            let vb = DebianVersion::parse(b).unwrap();
+            assert_eq!(cmp_sign(&va, &vb), *expected, "{a} cmp {b}");
+        }
+
+        // later_than convenience.
+        let old = DebianVersion::parse("1.0-0ubuntu1").unwrap();
+        let new = DebianVersion::parse("1.0-0ubuntu1.22.04.1").unwrap();
+        assert!(new.later_than(&old));
+        assert!(!old.later_than(&old));
+    }
 }

src/main.rs

@@ -252,6 +252,13 @@ fn main() {
             let cwd = current_dir_or_exit();
             if let Err(e) = pkh::build::build_source_package(Some(&cwd)) {
                 error!("{}", e);
+                // Unmet build dependencies/conflicts exit with status 3,
+                // like dpkg-buildpackage does.
+                if e.downcast_ref::<pkh::debian::deps::UnmetBuildDependencies>()
+                    .is_some()
+                {
+                    std::process::exit(3);
+                }
                 std::process::exit(1);
             }
         }