Upload meson test logs when a package build fails (#661)

makepkg runs check() inside the build container and meson writes each
test's output to the build tree, not to stdout. A failing test therefore
leaves only a summary line in the job log. Diagnosing it means reading
the package source and inferring the cause.

bin/build bind-mounts $SRC_DIR at /src, so the logs outlive the
container at src/**/meson-logs/ on the runner. Upload them when the
build step fails.

owe 0.2.7 showed the cost: owe:transition failed on aarch64 and passed
on x86_64, and CI carried no record of which assertion tripped.

Co-authored-by: Bjarne Oeverli <1419214+bjarneo@users.noreply.github.com>

.github/workflows/build-pr.yml

@@ -192,6 +192,19 @@ jobs:
         env:
           CONTAINER_ENGINE: docker
         run: bin/build --mirror edge --arch ${{ matrix.arch }} --package ${{ matrix.package }}
+      # makepkg's check() leaves meson's per-test output in the build tree,
+      # never on stdout, so a failing test shows only a summary line in this
+      # job log. bin/build bind-mounts $SRC_DIR at /src, so those logs outlive
+      # the container. Without this upload an arch-specific test failure
+      # cannot be diagnosed from CI at all (seen on owe 0.2.7, aarch64).
+      - name: Upload test logs
+        if: always() && steps.build.outcome == 'failure'
+        uses: actions/upload-artifact@v4
+        with:
+          name: test-logs-${{ matrix.package }}-${{ matrix.arch }}
+          path: src/**/meson-logs/
+          if-no-files-found: ignore
+          retention-days: 14
       # The artifact label carries the package directory's git tree hash so
       # the publish step can find the build for exactly the tree that merged.
       # The package file inside keeps makepkg's standard name untouched.