Merge pull request 'fix: distinguish Forgejo mergeability states' (#242) from codex-bot-andresmgsl/ceremony:build/236-forgejo-mergeable into main

Reviewed-on: #242
Reviewed-by: kimi-bot-andresmgsl <andres+4@heavyduty.builders>
Reviewed-by: glm-bot-andresmgsl <andres+5@heavyduty.builders>
Reviewed-by: claude-bot-andresmgsl <andres+1@heavyduty.builders>

changelog.d/236.md

@@ -0,0 +1,3 @@
+### Fixed
+
+- Forgejo drafts and fast-forward conflict-check windows no longer surface as merge conflicts when the API has not distinguished one (#236).

lib/forge-forgejo.sh

@@ -429,9 +429,12 @@ forge_pr_view() {
   status="$(forge_api "repos/$REPO/commits/$sha/status")" || return 1
   jq -n --argjson pr "$pr" --argjson st "$status" '
     {
-      mergeable: (if $pr.mergeable == true then "MERGEABLE"
+      # Forgejo folds checking, conflict, check error, and WIP into false.
-                  elif $pr.mergeable == false then "CONFLICTING"
+      # Draft must win because WIP makes the boolean carry no merge result (#236).
-                  else "UNKNOWN" end),
+      mergeable: (if $pr.draft == true then "UNKNOWN"
+                  elif $pr.mergeable == true then "MERGEABLE"
+                  elif $pr.merge_base == $pr.base.sha then "UNKNOWN"
+                  else "CONFLICTING" end),
       statusCheckRollup: [
         $st.statuses[]? | {
           __typename: "StatusContext",

test/forge-backends.test.sh

@@ -599,7 +599,7 @@ pr_view_stub() {
     printf 'HTTP/1.1 200 OK\r\nX-Total-Count: 1\r\n\r\n' >"$hdr"
     case "$url" in
       */status) printf '%s' "$FAKE_STATUS" >"$out" ;;
-      *) printf '{"head":{"sha":"abc"},"mergeable":true}' >"$out" ;;
+      *) printf '%s' "$FAKE_PR" >"$out" ;;
     esac
     return 0
   }
@@ -608,6 +608,7 @@ pr_view_stub() {
 FAKE_STATUS='{"state":"failure","statuses":[
   {"context":"ci / check","status":"success","created_at":"2026-08-02T10:00:00Z","updated_at":"2026-08-02T10:00:00Z"},
   {"context":"ci / check","status":"failure","created_at":"2026-08-02T09:00:00Z","updated_at":"2026-08-02T09:00:00Z"}]}'
+FAKE_PR='{"head":{"sha":"abc"},"base":{"sha":"base"},"merge_base":"ancestor","draft":false,"mergeable":true}'
 pr_view_stub
 view_json="$(REPO=o/r forge_pr_view 5)"
 check "pr_view maps createdAt" 0 "" \
@@ -616,6 +617,31 @@ check "pr_view maps completedAt" 0 "" \
   grep -q '"completedAt":' <<<"$view_json"
 check "pr_view maps mergeable to the UI string" 0 "" \
   grep -q '"mergeable": "MERGEABLE"' <<<"$view_json"
+
+# Forgejo folds conflict-checking, conflict-check errors, real conflicts, and
+# WIP into one false boolean. These fixtures pin the distinctions the API
+# object still lets the backend report honestly (#236).
+FAKE_PR='{"head":{"sha":"abc"},"base":{"sha":"base"},"merge_base":"ancestor","draft":true,"mergeable":false}'
+view_json="$(REPO=o/r forge_pr_view 5)"
+check "pr_view reports draft mergeability as unknown" 0 "" \
+  grep -q '"mergeable": "UNKNOWN"' <<<"$view_json"
+
+FAKE_PR='{"head":{"sha":"abc"},"base":{"sha":"base"},"merge_base":"base","draft":false,"mergeable":false}'
+view_json="$(REPO=o/r forge_pr_view 5)"
+check "pr_view reports a fast-forward false mergeability as unknown" 0 "" \
+  grep -q '"mergeable": "UNKNOWN"' <<<"$view_json"
+
+FAKE_PR='{"head":{"sha":"abc"},"base":{"sha":"base"},"merge_base":"ancestor","draft":false,"mergeable":false}'
+view_json="$(REPO=o/r forge_pr_view 5)"
+check "pr_view preserves a distinguishable real conflict" 0 "" \
+  grep -q '"mergeable": "CONFLICTING"' <<<"$view_json"
+
+# Unreachable on Forgejo: Mergeable() includes !IsWorkInProgress(). This
+# ordering fixture exists only to pin draft ahead of mergeable true (#236).
+FAKE_PR='{"head":{"sha":"abc"},"base":{"sha":"base"},"merge_base":"ancestor","draft":true,"mergeable":true}'
+view_json="$(REPO=o/r forge_pr_view 5)"
+check "pr_view reads draft before the mergeable boolean" 0 "" \
+  grep -q '"mergeable": "UNKNOWN"' <<<"$view_json"
 # The real proof: feed it to the production classifier and confirm the newer
 # SUCCESS wins over the older FAILURE regardless of array order.
 # shellcheck source=actions/labels-reconcile/labels-reconcile.sh