.github/workflows/release-exercise.yml

@@ -94,12 +94,25 @@ jobs:
         # consumes the tool end to end instead of hand-writing its output.
         # Same shape as test/release-chain.test.sh. The gh stub answers the
         # one API fact the ceremony path consults (the merged
-        # release-labeled PR) so nothing here talks to GitHub.
+        # release-labeled PR) so nothing here talks to a forge.
+        #
+        # The stub is gh-shaped, so the facts step below pins
+        # CEREMONY_FORGE=github: since #191 facts.sh selects a backend, and
+        # on a Forgejo runner it would otherwise pick the forgejo backend,
+        # which speaks curl and would walk straight past this stub to the
+        # real instance — reading the exercise's fixture SHA against the
+        # live repository and refusing it. The exercise rehearses the
+        # WIRING; which backend answers is lib/forge.sh's own contract,
+        # covered in test/forge*.test.sh.
         run: |
           mkdir -p "$RUNNER_TEMP/stub"
           cat > "$RUNNER_TEMP/stub/gh" <<'EOF'
           #!/usr/bin/env bash
-          if [ "$1" = api ]; then echo true; exit 0; fi
+          # The label read is GET commits/{sha}/pulls — a JSON array (#191).
+          if [ "$1" = api ]; then
+            echo '[{"merged_at":"2026-01-01T00:00:00Z","labels":[{"name":"release"}]}]'
+            exit 0
+          fi
           echo "gh stub: unexpected call: gh $*" >&2
           exit 97
           EOF
@@ -136,6 +149,9 @@ jobs:
           # back to the merge commit's first parent (#1 constraint 10).
           EVENT_BEFORE: ""
           VERSION_SOURCE: file
+          # The stub above is gh-shaped; pin the backend that uses it.
+          CEREMONY_FORGE: github
+          GITHUB_REPOSITORY: fixture/fixture
         # release.yml's step verbatim — same invocation, same
         # $GITHUB_OUTPUT plumbing — cwd'd at the fixture instead of the
         # workspace (the one thing a replay cannot inherit).