fix(vendor): let the backend rewrite a missing Bun workspace mirror

#300 sent every same-uuid ledger entry that was not healthy to exact
redownload before the backend ran. That includes a bun.lockb workspace
whose member-relative mirror tarball is missing or stale while the
canonical tarball still matches its ledger SHA-256. Offline, the
redownload failed with vendor_redownload_failed and skipped the backend,
which would have rewritten the mirror from the committed tarball; online
it downloaded an artifact the project already held.

A workspace mirror issue over a canonical tarball with a recorded
SHA-256 now goes straight to the backend, as repair also handles it
locally.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01NEUik3Qo9HQtYGVEAMs1Di

Author: claude

crates/socket-patch-cli/src/commands/vendor.rs

@@ -2454,12 +2454,25 @@ pub(crate) async fn vendor_records_reusing(
                     && (entry.artifact.file_inventory.is_some()
                         || vendor::artifact_is_file_shaped(&entry.artifact.path))
             }) {
-                if vendor::check_vendored_artifact(&common.cwd, entry, record).await
-                    != vendor::ArtifactHealth::Healthy
-                    || (entry.artifact.sha256.is_empty()
-                        && entry.artifact.file_inventory.is_none()
-                        && vendor::artifact_is_file_shaped(&entry.artifact.path))
-                {
+                let redownload =
+                    match vendor::check_vendored_artifact(&common.cwd, entry, record).await {
+                        vendor::ArtifactHealth::Healthy => {
+                            entry.artifact.sha256.is_empty()
+                                && entry.artifact.file_inventory.is_none()
+                                && vendor::artifact_is_file_shaped(&entry.artifact.path)
+                        }
+                        // Only a Bun member-relative mirror of the verified
+                        // canonical tarball is off: the backend rewrites it from
+                        // the committed tarball, offline too.
+                        vendor::ArtifactHealth::Corrupt { reason }
+                            if reason.starts_with("vendor_workspace_artifact_")
+                                && !entry.artifact.sha256.is_empty() =>
+                        {
+                            false
+                        }
+                        _ => true,
+                    };
+                if redownload {
                     if common.dry_run {
                         env.record(PatchEvent::new(PatchAction::Verified, candidate.clone()).with_details(serde_json::json!({"wouldRedownload": true, "path": entry.artifact.path})));
                         continue;

crates/socket-patch-cli/tests/vendor_eject_bun_lockb.rs

@@ -398,3 +398,35 @@ async fn rollback_and_offline_vendor_refuse_with_the_checkout_remedy() {
     );
     assert_eq!(p.lock(), hosted, "a refused rollback writes nothing");
 }
+
+/// A Bun workspace's member-relative mirror of the vendored tarball goes
+/// missing while the canonical tarball still matches its ledger SHA-256:
+/// an offline re-vendor rewrites the mirror from the committed tarball
+/// rather than refusing to redownload an artifact it already holds.
+#[tokio::test]
+async fn offline_vendor_rewrites_a_missing_workspace_mirror() {
+    let p = hosted_project("1.1.45-extensions").await;
+    // The pre-hosted lock (`git checkout -- bun.lockb`): a plain vendor.
+    std::fs::write(p.root().join("bun.lockb"), &p.pristine).unwrap();
+    stage_record(p.root());
+    let (code, env) = p.run_json(&["vendor"]);
+    assert_eq!(code, 0, "{env:#}");
+    let canonical = p
+        .root()
+        .join(format!(".socket/vendor/npm/{UUID}/minimist-1.2.2.tgz"));
+    let mirror = p.root().join(format!(
+        "packages/helper/.socket/vendor/npm/{UUID}/minimist-1.2.2.tgz"
+    ));
+    let tarball = std::fs::read(&canonical).unwrap();
+    assert_eq!(std::fs::read(&mirror).unwrap(), tarball, "{env:#}");
+    std::fs::remove_file(&mirror).unwrap();
+
+    let (code, env) = p.run_json(&["vendor", "--offline"]);
+    assert_eq!(code, 0, "{env:#}");
+    assert!(
+        !codes(&env).iter().any(|c| c == "vendor_redownload_failed"),
+        "{env:#}"
+    );
+    assert_eq!(std::fs::read(&mirror).unwrap(), tarball);
+    assert_eq!(std::fs::read(&canonical).unwrap(), tarball);
+}