huskies: merge 919

server/src/pipeline_state/tests.rs

@@ -687,6 +687,8 @@ fn merge_failure_transition_emits_event_with_full_reason() {
 fn merge_failure_plus_merge_failed_is_self_loop() {
     let s = Stage::MergeFailure {
         reason: "initial failure".into(),
+        feature_branch: fb("feature/story-1"),
+        commits_ahead: nz(1),
     };
     let result = transition(
         s,
@@ -758,18 +760,20 @@ fn repeated_merge_failure_apply_transition_no_error_no_duplicate_notification()
     );
 }
 
-// ── Story 893: MergeFailure + Unblock → Coding (retry) ─────────────
+// ── Story 919: MergeFailure + Unblock → Merge (re-attempt) ─────────
 
-/// AC1: `MergeFailure + Unblock` transitions to `Coding` (retry), not `Backlog`.
+/// AC1: `MergeFailure + Unblock` transitions to `Merge` (re-attempt), not `Coding` or `Backlog`.
 #[test]
-fn merge_failure_unblock_returns_to_coding() {
+fn merge_failure_unblock_returns_to_merge() {
     let s = Stage::MergeFailure {
         reason: "conflicts in server/src/main.rs".into(),
+        feature_branch: fb("feature/story-42"),
+        commits_ahead: nz(3),
     };
     let result = transition(s, PipelineEvent::Unblock).unwrap();
     assert!(
-        matches!(result, Stage::Coding),
-        "MergeFailure + Unblock should return to Coding for immediate retry, got: {result:?}"
+        matches!(result, Stage::Merge { .. }),
+        "MergeFailure + Unblock should return to Merge for immediate re-attempt, got: {result:?}"
     );
 }
 
@@ -778,6 +782,8 @@ fn merge_failure_unblock_returns_to_coding() {
 fn merge_failure_demote_returns_to_backlog() {
     let s = Stage::MergeFailure {
         reason: "conflicts".into(),
+        feature_branch: fb("feature/story-1"),
+        commits_ahead: nz(1),
     };
     let result = transition(s, PipelineEvent::Demote).unwrap();
     assert!(
@@ -794,6 +800,8 @@ fn merge_failure_demote_returns_to_backlog() {
 fn merge_failure_accept_pure_transition() {
     let s = Stage::MergeFailure {
         reason: "conflicts unresolvable".into(),
+        feature_branch: fb("feature/story-1"),
+        commits_ahead: nz(1),
     };
     let result = transition(s, PipelineEvent::Accepted).unwrap();
     assert!(
@@ -852,4 +860,49 @@ fn merge_failure_accept_moves_to_done_via_crdt() {
     );
 }
 
+// ── Story 919: MergeFailure + Unblock → Merge (regression) ─────────
+
+/// AC3: CRDT-based regression — set stage to `MergeFailure`, call `unblock_story`
+/// via `apply_transition`, assert the Stage register becomes `Stage::Merge`.
+#[test]
+fn merge_failure_unblock_moves_to_merge_via_crdt() {
+    crate::crdt_state::init_for_test();
+    crate::db::ensure_content_store();
+
+    let story_id = "99919_story_merge_failure_unblock";
+    crate::db::write_item_with_content(
+        story_id,
+        "merge_failure",
+        "---\nname: MergeFailure Unblock Regression\n---\n# Story\n",
+        crate::db::ItemMeta::named("MergeFailure Unblock Regression"),
+    );
+
+    let fired = super::apply::apply_transition(story_id, PipelineEvent::Unblock, None)
+        .expect("MergeFailure + Unblock should succeed");
+
+    assert!(
+        matches!(fired.before, Stage::MergeFailure { .. }),
+        "fired.before should be MergeFailure: {:?}",
+        fired.before
+    );
+    assert!(
+        matches!(fired.after, Stage::Merge { .. }),
+        "fired.after should be Merge, not Coding or Backlog: {:?}",
+        fired.after
+    );
+
+    let item = read_typed(story_id)
+        .expect("CRDT read should succeed")
+        .expect("item should exist");
+    assert_eq!(
+        item.stage.dir_name(),
+        "merge",
+        "CRDT stage should be merge after MergeFailure + Unblock"
+    );
+    assert!(
+        !matches!(item.stage, Stage::MergeFailure { .. }),
+        "MergeFailure variant must not remain after Unblock"
+    );
+}
+
 // ── ProjectionError Display ─────────────────────────────────────────

server/src/pipeline_state/transition.rs

@@ -197,13 +197,34 @@ pub fn transition(state: Stage, event: PipelineEvent) -> Result<Stage, Transitio
         }
 
         // ── MergeFailed: Merge → MergeFailure (recoverable intermediate) ──
-        (Merge { .. }, MergeFailed { reason }) => Ok(MergeFailure { reason }),
+        (
+            Merge {
+                feature_branch,
+                commits_ahead,
+            },
+            MergeFailed { reason },
+        ) => Ok(MergeFailure {
+            reason,
+            feature_branch,
+            commits_ahead,
+        }),
 
         // ── MergeFailure self-loop: repeated failure is a no-op ─────────────
         // When the mergemaster retries and fails again while the story is already
         // in MergeFailure, treat it as a silent self-transition so callers can
         // detect the no-op via `fired.before == MergeFailure` and skip re-notifying.
-        (MergeFailure { .. }, MergeFailed { reason }) => Ok(MergeFailure { reason }),
+        (
+            MergeFailure {
+                feature_branch,
+                commits_ahead,
+                ..
+            },
+            MergeFailed { reason },
+        ) => Ok(MergeFailure {
+            reason,
+            feature_branch,
+            commits_ahead,
+        }),
 
         (Merge { .. }, MergeFailedFinal { reason }) => Ok(Archived {
             archived_at: now,
@@ -278,7 +299,7 @@ pub fn transition(state: Stage, event: PipelineEvent) -> Result<Stage, Transitio
         (Stage::ReviewHold { resume_to, .. }, ReviewHoldCleared) => Ok(*resume_to),
 
         // ── MergemasterAttempted: MergeFailure → MergeFailureFinal ─────
-        (MergeFailure { reason }, MergemasterAttempted) => Ok(MergeFailureFinal { reason }),
+        (MergeFailure { reason, .. }, MergemasterAttempted) => Ok(MergeFailureFinal { reason }),
         (MergeFailureFinal { reason }, MergemasterAttempted) => Ok(MergeFailureFinal { reason }),
 
         // ── Unblock: from Frozen/ReviewHold → resume_to ────────────────
@@ -288,11 +309,21 @@ pub fn transition(state: Stage, event: PipelineEvent) -> Result<Stage, Transitio
         // ── Unblock: Blocked → Coding ─────────────────────────────────
         (Blocked { .. }, Unblock) => Ok(Coding),
 
-        // ── Unblock MergeFailure → Coding (retry) ────────────────────────
-        // `unblock_story` on a failed merge re-enters the coding stage so a
-        // coder agent can rework the branch, rather than routing back through
-        // the backlog (which would require an extra DepsMet promotion step).
-        (MergeFailure { .. }, Unblock) => Ok(Coding),
+        // ── Unblock MergeFailure → Merge (re-attempt) ────────────────────
+        // `unblock_story` on a failed merge re-queues it for merge, restoring
+        // the exact `Merge { feature_branch, commits_ahead }` that was in place
+        // before the failure so the mergemaster can retry immediately.
+        (
+            MergeFailure {
+                feature_branch,
+                commits_ahead,
+                ..
+            },
+            Unblock,
+        ) => Ok(Merge {
+            feature_branch,
+            commits_ahead,
+        }),
 
         // ── Demote MergeFailure → Backlog (manual parking) ───────────────
         // Lets operators park a failed-merge story in the backlog without an

server/src/pipeline_state/types.rs

@@ -108,9 +108,15 @@ pub enum Stage {
 
     /// Merge pipeline failed (conflicts or gate failures). Story is held here
     /// awaiting human intervention or retry.  Unlike `Archived(MergeFailed)`,
-    /// this is a recoverable intermediate state — `Unblock` returns to `Coding`
-    /// (immediate agent retry) and `Demote` returns to `Backlog` (manual park).
-    MergeFailure { reason: String },
+    /// this is a recoverable intermediate state — `Unblock` returns to `Merge`
+    /// (re-queues the merge) and `Demote` returns to `Backlog` (manual park).
+    MergeFailure {
+        reason: String,
+        /// Branch and commit count preserved from the preceding `Merge` state
+        /// so `Unblock` can reconstruct the exact `Merge` variant.
+        feature_branch: BranchName,
+        commits_ahead: NonZeroU32,
+    },
 
     /// Merge pipeline failed AND mergemaster has already been auto-spawned to
     /// recover; the agent gave up.  The story stays here awaiting human
@@ -234,6 +240,8 @@ impl Stage {
             }),
             "merge_failure" => Some(Stage::MergeFailure {
                 reason: String::new(),
+                feature_branch: BranchName(String::new()),
+                commits_ahead: NonZeroU32::new(1).expect("1 is non-zero"),
             }),
             "merge_failure_final" => Some(Stage::MergeFailureFinal {
                 reason: String::new(),