huskies: merge 1051

server/src/agents/lifecycle.rs

@@ -496,6 +496,25 @@ pub fn move_story_to_stage(story_id: &str, target_stage: &str) -> Result<(String
     Ok((from_name.to_string(), target_stage.to_string()))
 }
 
+/// Transition a story from `Stage::MergeFailure` to `Stage::Merge` when the
+/// deterministic-merge pipeline starts a retry attempt.
+///
+/// Preserves `feature_branch` and `commits_ahead` from the preceding
+/// `MergeFailure` state so the retry continues with the exact same branch.
+/// If the story is already in `Stage::Merge` or any other stage, this is a
+/// silent no-op — callers do not need to pre-check the current stage.
+///
+/// Called by `start_merge_agent_work` before the squash-merge pipeline starts
+/// so the UI shows an active merge state rather than a stale failure indicator
+/// (story 1051, AC 1 and AC 4).
+pub fn transition_merge_failure_to_retry(story_id: &str) -> Result<(), String> {
+    match apply_transition(story_id, PipelineEvent::MergeRetryStarted, None) {
+        Ok(_) => Ok(()),
+        Err(ApplyError::InvalidTransition(_)) | Err(ApplyError::NotFound(_)) => Ok(()),
+        Err(e) => Err(e.to_string()),
+    }
+}
+
 /// Move a bug from `work/2_current/` or `work/1_backlog/` to `work/5_done/`.
 ///
 /// Idempotent if already in `5_done/`. Errors if not found in `2_current/` or `1_backlog/`.
@@ -1028,6 +1047,113 @@ mod tests {
         );
     }
 
+    // ── Story 1051: MergeFailure → Merge retry transition ───────────────────
+
+    /// AC1 (story 1051): when the deterministic-merge pipeline starts on a
+    /// MergeFailure story, transition_merge_failure_to_retry moves it to Merge.
+    #[test]
+    fn transition_merge_failure_to_retry_moves_to_merge() {
+        crate::crdt_state::init_for_test();
+        crate::db::ensure_content_store();
+
+        let story_id = "99105_story_merge_retry_1051";
+        crate::db::write_item_with_content(
+            story_id,
+            "merge_failure",
+            "---\nname: Merge Retry Test\n---\n",
+            crate::db::ItemMeta::named("Merge Retry Test"),
+        );
+
+        transition_merge_failure_to_retry(story_id).expect("must succeed for MergeFailure story");
+
+        let item = crate::pipeline_state::read_typed(story_id)
+            .expect("CRDT read must succeed")
+            .expect("item must exist");
+        assert_eq!(
+            item.stage.dir_name(),
+            "merge",
+            "MergeFailure story must be in Merge after retry transition: {:?}",
+            item.stage
+        );
+        assert!(
+            matches!(item.stage, Stage::Merge { .. }),
+            "stage must be Stage::Merge variant: {:?}",
+            item.stage
+        );
+    }
+
+    /// AC1 (story 1051): transition_merge_failure_to_retry is a no-op when the
+    /// story is already in Stage::Merge — callers do not need to pre-check.
+    #[test]
+    fn transition_merge_failure_to_retry_noop_when_already_merge() {
+        crate::crdt_state::init_for_test();
+        crate::db::ensure_content_store();
+
+        let story_id = "99106_story_already_merge_1051";
+        crate::db::write_item_with_content(
+            story_id,
+            "4_merge",
+            "---\nname: Already Merge\n---\n",
+            crate::db::ItemMeta::named("Already Merge"),
+        );
+
+        // Must not error even though story is in Merge, not MergeFailure.
+        assert!(
+            transition_merge_failure_to_retry(story_id).is_ok(),
+            "must be a no-op when story is in Merge"
+        );
+
+        let item = crate::pipeline_state::read_typed(story_id)
+            .expect("CRDT read must succeed")
+            .expect("item must exist");
+        assert_eq!(
+            item.stage.dir_name(),
+            "merge",
+            "story must still be in merge after no-op: {:?}",
+            item.stage
+        );
+    }
+
+    /// AC3 (story 1051): after a MergeRetryStarted transition (MergeFailure →
+    /// Merge), a subsequent MergeFailed event sets a fresh failure — the
+    /// transition's `before` stage is Merge (not MergeFailure), confirming the
+    /// failure flag is not carried over from the previous attempt.
+    #[test]
+    fn merge_retry_followed_by_failure_sets_fresh_merge_failure() {
+        crate::crdt_state::init_for_test();
+        crate::db::ensure_content_store();
+
+        let story_id = "99107_story_fresh_failure_1051";
+        crate::db::write_item_with_content(
+            story_id,
+            "merge_failure",
+            "---\nname: Fresh Failure Test\n---\n",
+            crate::db::ItemMeta::named("Fresh Failure Test"),
+        );
+
+        // Retry start: MergeFailure → Merge.
+        transition_merge_failure_to_retry(story_id).expect("retry start must succeed");
+
+        // Pipeline fails again: Merge → MergeFailure.
+        let fired = transition_to_merge_failure(
+            story_id,
+            MergeFailureKind::GatesFailed("new gate output".to_string()),
+        )
+        .expect("transition_to_merge_failure must succeed after retry");
+
+        // 'before' must be Merge (fresh failure, not a self-loop from MergeFailure).
+        assert!(
+            matches!(fired.before, Stage::Merge { .. }),
+            "before must be Merge, proving this is a fresh failure not a self-loop: {:?}",
+            fired.before
+        );
+        assert!(
+            matches!(fired.after, Stage::MergeFailure { .. }),
+            "after must be MergeFailure: {:?}",
+            fired.after
+        );
+    }
+
     /// Bug 226: feature_branch_has_unmerged_changes returns false when no
     /// feature branch exists.
     #[test]

server/src/agents/pool/pipeline/merge/runner.rs

@@ -100,6 +100,16 @@ impl AgentPool {
             }
         }
 
+        // Story 1051: if the story is in MergeFailure, transition it to Merge
+        // before starting the pipeline so the UI shows an active retry state
+        // rather than the stale failure indicator (AC 1, AC 4).
+        if let Err(e) = crate::agents::lifecycle::transition_merge_failure_to_retry(story_id) {
+            slog!(
+                "[merge] Could not transition '{story_id}' from MergeFailure to Merge: {e} \
+                 (merge will proceed regardless)"
+            );
+        }
+
         // Insert Running job into CRDT.
         let started_at = unix_now();
         crate::crdt_state::write_merge_job(