new: surface cargo vendor failures and pin the vendoring toolchain

src/new/questions.rs

@@ -24,7 +24,7 @@ use indicatif::MultiProgress;
 
 use crate::new::detect::{self, Detection};
 use crate::new::options::{self, NewCli, NewOptions, SourceDir, TemplateId};
-use crate::new::templates::{self, ProbeResult};
+use crate::new::templates::{self, ProbeResult, ScaffoldOutcome};
 use crate::ui::prompt;
 
 /// Answer of the "where is the source code?" question: fresh skeleton.
@@ -411,10 +411,17 @@ async fn run_wizard(mut cli: NewCli) -> Result<NewOptions, Box<dyn Error>> {
 /// (`pkh build`, offered yes) and the binary build (`pkh deb`, offered no —
 /// it needs network + build deps). A failed verification build never undoes
 /// the scaffold: the error is printed together with the manual next steps.
-pub async fn offer_verification(opts: &NewOptions, multi: &MultiProgress, no_verify: bool) {
-    if no_verify || !is_interactive() {
-        return;
-    }
+///
+/// When the scaffold's vendoring step failed (`outcome`), a prominent notice
+/// states that the tree will not build until the dependencies are vendored —
+/// printed with or without a TTY — and the build offer is reworded with its
+/// default flipped to *no*.
+pub async fn offer_verification(
+    opts: &NewOptions,
+    outcome: &ScaffoldOutcome,
+    multi: &MultiProgress,
+    no_verify: bool,
+) {
     let tree = opts.target_dir(&std::env::current_dir().unwrap_or_default());
     let display = crate::ui::display_path(&tree);
     let display = if display.is_empty() {
@@ -423,7 +430,30 @@ pub async fn offer_verification(opts: &NewOptions, multi: &MultiProgress, no_ver
         display
     };
 
-    let verify_source = match prompt::confirm("Verify with `pkh build` now?", true) {
+    if outcome.vendoring_failed {
+        // Set apart from the surrounding success output by blank lines: a
+        // single warning between two success lines is easy to miss.
+        println!();
+        log::warn!(
+            "The Cargo dependencies could NOT be vendored: this package will \
+             not build until the vendoring is completed by hand:\n\
+             \x20 1. `cd {display} && cargo vendor`\n\
+             \x20 2. add the printed source replacement to .cargo/config.toml, \
+             plus `[net] offline = true`"
+        );
+        println!();
+    }
+
+    if no_verify || !is_interactive() {
+        return;
+    }
+
+    let build_offer = if outcome.vendoring_failed {
+        "Verify with `pkh build` now? (it will fail until dependencies are vendored)"
+    } else {
+        "Verify with `pkh build` now?"
+    };
+    let verify_source = match prompt::confirm(build_offer, !outcome.vendoring_failed) {
         Ok(answer) => answer,
         Err(_) => return,
     };
@@ -720,8 +750,12 @@ pub fn summary_text(opts: &NewOptions) -> String {
                 lines.push(format!("  Depends           {}", opts.depends.join(", ")));
             }
         } else if opts.template == TemplateId::Rust {
-            lines
-                .push("  debian/rules      cargo build --release --offline (vendored)".to_string());
+            // Nothing is vendored yet at this point: only announce that the
+            // generation will attempt it.
+            lines.push(
+                "  debian/rules      cargo build --release --offline (vendored at generation)"
+                    .to_string(),
+            );
         } else {
             lines.push(format!("  debian/rules      {}", template.rules_dh_line()));
         }
@@ -948,6 +982,19 @@ mod tests {
         assert!(text.contains("debian/watch      release watcher"), "{text}");
     }
 
+    /// The rust summary only announces the vendoring attempt of the
+    /// generation, it must not assert an outcome that has not been tried
+    /// yet (regression: it claimed "(vendored)" before generating).
+    #[test]
+    fn summary_screen_rust_does_not_presume_vendoring() {
+        let text = summary_text(&opts(Tid::Rust));
+        assert!(
+            text.contains("cargo build --release --offline (vendored at generation)"),
+            "{text}"
+        );
+        assert!(!text.contains("(vendored)"), "{text}");
+    }
+
     #[test]
     fn answer_validators() {
         assert!(validate_revision_answer("1").is_ok());