fix(ci): load Hangar page during old-tag backfills (#84)

Author: robinbraemer

.github/workflows/release.yml

@@ -284,6 +284,9 @@ jobs:
         env:
           HANGAR_API_TOKEN: ${{ secrets.HANGAR_API_TOKEN }}
           RELEASE_TAG: ${{ steps.release-tag.outputs.tag }}
+          # The checkout may be an old release tag that predates the Hangar
+          # page source. Read it from the exact commit supplying this workflow.
+          WORKFLOW_SHA: ${{ github.workflow_sha }}
         run: |
           set -euo pipefail
 
@@ -296,6 +299,10 @@ jobs:
             echo "::error::Release tag is empty; cannot publish a Hangar version."
             exit 1
           fi
+          if [ -z "${WORKFLOW_SHA:-}" ]; then
+            echo "::error::Workflow commit is empty; cannot load the authoritative Hangar page."
+            exit 1
+          fi
 
           API="https://hangar.papermc.io/api/v1"
           PROJECT="Connect"
@@ -333,7 +340,16 @@ jobs:
 
           # Sync the public resource page before creating an immutable version.
           # If the token lacks edit_page, fail before partially publishing.
-          jq -n --rawfile content .github/hangar-description.md \
+          # Backfills check out the release tag, which may predate this file,
+          # so fetch it from the immutable commit that supplied the workflow.
+          curl -sS --fail -A "$UA" \
+            "https://raw.githubusercontent.com/$GITHUB_REPOSITORY/$WORKFLOW_SHA/.github/hangar-description.md" \
+            -o "$TMP/hangar-description.md"
+          if [ ! -s "$TMP/hangar-description.md" ]; then
+            echo "::error::The authoritative Hangar resource page is empty."
+            exit 1
+          fi
+          jq -n --rawfile content "$TMP/hangar-description.md" \
             '{path: "", content: $content}' > "$TMP/page.json"
           PAGE_CODE="$(api "$TMP/page-response.json" \
             -X PATCH "$API/pages/edit/$PROJECT" \

core/src/test/java/com/minekube/connect/release/ReleaseHangarPublishTest.java

@@ -178,6 +178,28 @@ void hangarPublishSyncsTheCheckedInResourcePage() throws Exception {
                 "release workflow does not sync the checked-in resource page");
     }
 
+    @Test
+    @SuppressWarnings("unchecked")
+    void hangarDescriptionComesFromTheWorkflowCommitWhenBackfillingAnOldTag() throws Exception {
+        List<Map<String, Object>> steps = readBuildJobSteps();
+        Map<String, Object> step = hangarStep(steps);
+
+        Object env = step.get("env");
+        assertTrue(env instanceof Map, "\"" + HANGAR_STEP + "\" declares no env block");
+        Object workflowSha = ((Map<String, Object>) env).get("WORKFLOW_SHA");
+        assertTrue(workflowSha instanceof String
+                        && ((String) workflowSha).contains("github.workflow_sha"),
+                "\"" + HANGAR_STEP + "\" does not identify the commit containing its workflow");
+
+        String script = hangarScript(steps);
+        assertTrue(script.contains("$GITHUB_REPOSITORY/$WORKFLOW_SHA/"
+                        + ".github/hangar-description.md"),
+                "Hangar description is not loaded from the exact workflow commit");
+        assertTrue(script.contains("--rawfile content \"$TMP/hangar-description.md\""),
+                "Hangar page sync still reads the checked-out release tag, where a backfill file "
+                        + "may not exist");
+    }
+
     @Test
     void hangarPublishVerifiesStoredDigestsAndJarMagic() throws Exception {
         String script = hangarScript(readBuildJobSteps());