deb,build: export ddebs from binary builds

dh_strip registers debug-symbol packages in debian/files under their
renamed .ddeb name; they are deliverables of the build just like the
regular .debs. Both artifact-type filters, the one collecting the
build's artifacts and the one feeding the .buildinfo/.changes
checksum sections, accepted only deb and udeb, so every ddeb a build
produced was silently discarded: nothing exported next to the .debs,
nothing in the upload metadata.

The filter is now a shared FilesEntry::is_binary_artifact() predicate
(plus unit tests) used by both call sites, so the two cannot drift
apart again.

One dpkg distinction has to be copied rather than shared:
dpkg-genchanges lists only deb/udeb packages in the changes' Binary:
and Description (a ddeb travels in Files and the checksum sections
but is not a listed binary of the upload), while dpkg-genbuildinfo
lists every binary artifact's package, ddebs included. The package
list is therefore accumulated twice, once per consumer.

The binary-metadata differential fixture gains a Package-Type: ddeb
package, so the native .changes/.buildinfo generation is compared
against real dpkg with a ddeb present. Without the fix the comparison
fails on the checksum sections (golden distributes the ddeb, ours
dropped it); with it every field matches.

src/build/binary.rs

@@ -92,7 +92,7 @@ pub fn generate_binary_metadata(
     // ------------------------------------------------------------------
     let artifact_names: Vec<String> = files_list
         .iter()
-        .filter(|e| matches!(e.package_type.as_deref(), Some("deb") | Some("udeb")))
+        .filter(|e| e.is_binary_artifact())
         .map(|e| e.filename.clone())
         .collect();
 
@@ -159,16 +159,28 @@ pub fn generate_binary_metadata(
     // ------------------------------------------------------------------
     // Binary package names and descriptions
     // ------------------------------------------------------------------
+    // dpkg-genchanges lists only deb/udeb packages in `Binary:` (a ddeb
+    // is distributed through Files but is not a listed binary of the
+    // upload), while dpkg-genbuildinfo lists every binary artifact's
+    // package, ddebs included.
     let mut binaries: Vec<String> = Vec::new();
+    let mut buildinfo_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)
-        {
+        let Some(e) = files_list.get(name) else {
+            continue;
+        };
+        let Some(pkg) = &e.package else {
+            continue;
+        };
+        if !buildinfo_binaries.contains(pkg) {
+            buildinfo_binaries.push(pkg.clone());
+        }
+        if e.package_type.as_deref() != Some("ddeb") && !binaries.contains(pkg) {
             binaries.push(pkg.clone());
         }
     }
     binaries.sort();
+    buildinfo_binaries.sort();
 
     // Description lines: first line of each binary stanza's Description,
     // formatted exactly like dpkg-genchanges, sorted.
@@ -238,7 +250,7 @@ pub fn generate_binary_metadata(
     let buildinfo_doc =
         crate::build::buildinfo::render_buildinfo(&crate::build::buildinfo::BuildInfoInput {
             source: source_display.clone(),
-            binaries: binaries.clone(),
+            binaries: buildinfo_binaries.clone(),
             architecture: buildinfo_arch_values.join(" "),
             version: entry.version.full(),
             binary_only_changes: binary_only_changes.clone(),

src/build/mod.rs

@@ -1889,19 +1889,22 @@ Provides: virtual-thing (= 2.0), plain-virtual
     }
 
     /// debian/control shared by the binary-metadata differential cases: one
-    /// arch:any deb and one arch:all udeb.
+    /// arch:any deb, one arch:all udeb and one arch:all ddeb (the
+    /// debug-symbol shape dh_strip leaves behind: the package type
+    /// drives the file name in debian/files).
     fn binary_test_control(name: &str) -> String {
         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"
+             Package: {name}-u\nPackage-Type: udeb\nArchitecture: all\nDescription: test udeb\n short\n\n\
+             Package: {name}-d\nPackage-Type: ddeb\nArchitecture: all\nDescription: test ddeb\n short\n"
         )
     }
 
     /// debian/rules driving dpkg-gencontrol/dpkg-deb directly (no debhelper).
     fn binary_test_rules(name: &str) -> String {
         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"
+            "#!/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 $@\n\nbinary: build\n\trm -rf debian/{name} debian/{name}-u debian/{name}-d\n\tmkdir -p debian/{name}/usr/bin debian/{name}/DEBIAN\n\tcp -r debian/tmp/. debian/{name}/\n\tdpkg-gencontrol -p{name} -Pdebian/{name}\n\tdpkg-deb --build debian/{name} ..\n\tmkdir -p debian/{name}-u/usr/share debian/{name}-u/DEBIAN\n\techo data > debian/{name}-u/usr/share/data.txt\n\tdpkg-gencontrol -p{name}-u -Pdebian/{name}-u\n\tdpkg-deb --build debian/{name}-u ..\n\tmv ../{name}-u_$(V)_all.deb ../{name}-u_$(V)_all.udeb\n\tmkdir -p debian/{name}-d/usr/share debian/{name}-d/DEBIAN\n\techo data > debian/{name}-d/usr/share/data.txt\n\tdpkg-gencontrol -p{name}-d -Pdebian/{name}-d\n\tdpkg-deb --build debian/{name}-d ..\n\tmv ../{name}-d_$(V)_all.deb ../{name}-d_$(V)_all.ddeb\n\nclean:\n\trm -rf debian/tmp debian/{name} debian/{name}-u debian/{name}-d build-stamp debian/files debian/*.substvars\n\n.PHONY: build binary clean\n"
         )
     }
 

src/deb/local.rs

@@ -939,7 +939,7 @@ fn collect_binary_artifacts(
     let upload_dir = Path::new(build_root);
     let mut artifacts = Vec::new();
     for entry in files_list.iter() {
-        if matches!(entry.package_type.as_deref(), Some("deb") | Some("udeb")) {
+        if entry.is_binary_artifact() {
             artifacts.push(upload_dir.join(&entry.filename));
         }
     }

src/debian/files.rs

@@ -46,6 +46,21 @@ impl FilesEntry {
         entry.priority = priority.to_string();
         entry
     }
+
+    /// Whether this entry is a binary-package artifact that must be
+    /// exported from the build: a `.deb`, a `.udeb`, or a `.ddeb`.
+    ///
+    /// Debug-symbol packages are registered in `debian/files` by
+    /// `dh_strip` under their renamed `.ddeb` name; they are as much
+    /// a deliverable of the build as the regular `.deb`s (they belong
+    /// in the upload set), so any filter keyed on artifact type has
+    /// to accept them.
+    pub fn is_binary_artifact(&self) -> bool {
+        matches!(
+            self.package_type.as_deref(),
+            Some("deb") | Some("udeb") | Some("ddeb")
+        )
+    }
 }
 
 /// Derive metadata from an artifact file name following the common
@@ -243,6 +258,21 @@ mod tests {
         assert_eq!(e.package_type, None);
     }
 
+    #[test]
+    fn binary_artifact_filter_accepts_ddebs() {
+        let deb = parse_filename("hello_2.10-3_amd64.deb").unwrap();
+        let udeb = parse_filename("hello_2.10-3_amd64.udeb").unwrap();
+        let ddeb = parse_filename("hello-dbgsym_2.10-3_amd64.ddeb").unwrap();
+        let buildinfo = parse_filename("hello_2.10-3_amd64.buildinfo").unwrap();
+        let changes = parse_filename("hello_2.10-3_amd64.changes").unwrap();
+
+        assert!(deb.is_binary_artifact());
+        assert!(udeb.is_binary_artifact());
+        assert!(ddeb.is_binary_artifact(), "ddebs must be exported");
+        assert!(!buildinfo.is_binary_artifact());
+        assert!(!changes.is_binary_artifact());
+    }
+
     #[test]
     fn load_save_roundtrip() {
         let dir = tempfile::tempdir().unwrap();