fix(mergify): auto-route via queue_conditions, not pull_request_rules

.github/workflows/ci.yml

@@ -21,10 +21,6 @@ on:
   push:
     branches: [main]
   pull_request:
-    # `labeled` / `unlabeled` listed so adding the `ci:run` label fires a
-    # workflow run. Defaults [opened, synchronize, reopened] must be re-
-    # declared because specifying `types:` drops the implicit defaults.
-    types: [opened, synchronize, reopened, labeled, unlabeled]
     branches: [main]
   # Merge queue: GitHub builds a temporary `gh-readonly-queue/main/...` branch
   # combining PRs + main, and runs CI on that combined state. Without this
@@ -199,25 +195,14 @@ jobs:
       fail-fast: false
       matrix:
         os: [ubuntu-latest, macos-latest, windows-latest]
-    # PR-time test gating: the author opts in by adding the `ci:run` label.
-    # Pattern is the GitHub-personal-repo substitute for merge queue / self-
-    # approve (PR authors can't approve their own PRs). Once labeled,
-    # subsequent `synchronize` events keep firing test as long as the label
-    # is present; remove the label to pause test on further pushes.
-    #
-    # Non-PR events (push:main / merge_group / workflow_dispatch) always run
-    # test — they're the post-merge / pre-merge-queue / manual paths and have
-    # no opt-in semantic.
-    #
-    # test-result aggregator below distinguishes PR-skipped (blocking — author
-    # forgot the label) from non-PR-skipped (allowed — docs-only short-circuit
-    # on push:main is legitimate).
+    # Test fires unconditionally on every PR + push + merge_group. Author
+    # opt-in via `ci:run` label was removed once Mergify queue_conditions
+    # took over the merge gate — the label dance conflicted with auto-
+    # routing (queue needs Test green; label toggle to fire Test caused
+    # cancellation races) and was redundant with `detect-changes` already
+    # skipping the test job for docs-only changes.
     if: |
       !(contains(github.event.pull_request.title, '[skip ci]') || contains(github.event.head_commit.message, '[skip ci]'))
-      && (
-        github.event_name != 'pull_request'
-        || contains(github.event.pull_request.labels.*.name, 'ci:run')
-      )
     env:
       # 14 tree-sitter parsers × 30+ test binaries × debug-info defaulted to
       # `true` produced ~30 GB in target/debug/deps/ and filled the ubuntu
@@ -306,11 +291,8 @@ jobs:
   #
   # Skip-handling rules:
   #   - `success` → pass (real green)
-  #   - `skipped` on non-PR event → pass (docs-only short-circuit on push:main
-  #     is legitimate; nothing to validate)
-  #   - `skipped` on PR event → FAIL (author opted out by not adding `ci:run`
-  #     label, but branch protection requires test green before merge — this
-  #     forces the label to come on before merge can happen)
+  #   - `skipped` → pass (only possible via [skip ci] in title/message; legit
+  #     opt-out, gate is title-prefix not label)
   #   - anything else (failure / cancelled) → FAIL
   test-result:
     name: Test (all platforms)
@@ -327,13 +309,9 @@ jobs:
           if [ "$TEST_RESULT" = "success" ]; then
             exit 0
           fi
-          if [ "$TEST_RESULT" = "skipped" ] && [ "$EVENT_NAME" != "pull_request" ]; then
-            echo "✓ Skipped on $EVENT_NAME — docs-only short-circuit OK"
-            exit 0
-          fi
           if [ "$TEST_RESULT" = "skipped" ]; then
-            echo "::error::Test was skipped on PR — add 'ci:run' label to fire it before merge"
-            exit 1
+            echo "✓ Skipped — [skip ci] in commit/title"
+            exit 0
           fi
           echo "::error::At least one test shard failed or was cancelled"
           exit 1

.mergify.yml

@@ -1,58 +1,35 @@
 # Mergify config.
 #
-# Per Mergify best practice:
-# - queue_rules pin `base=` so cross-target-branch PRs can't batch together
-#   (Mergify speculative-trial would re-base each onto the wrong tip).
-# - One pull_request_rule per (area, base) pair selects the target queue
-#   explicitly; without an explicit routing rule, Mergify can't know which
-#   area-specific queue a PR belongs in.
-# - Priority is set declaratively per rule via `queue.priority`, so the
-#   risk-low PRs land at the front of their area queue.
+# Routing pattern (modern Mergify, post-2024):
+# - Each queue_rule carries its own `queue_conditions` — labels, base, and
+#   required-check list a PR must satisfy to auto-enter THIS queue.
+# - `merge_conditions` is what gates the actual merge once embarked.
+# - No `pull_request_rules` needed for routing: Mergify checks each PR
+#   against every queue's `queue_conditions` and embarks it into the first
+#   match. Order queue_rules from most-specific to least-specific.
 #
-# The required-check list is duplicated across routing rules — YAML anchors
-# splice nested lists which Mergify rejects, so DRY isn't available here.
+# Why not pull_request_rules.queue?
+# - That action exists for EXPLICIT enqueuing (commands, advanced filters),
+#   not auto-routing. With only pull_request_rules, the Mergify Merge Queue
+#   check stays at "Merge queue is ready" without ever embarking — confirmed
+#   on PR #386 (manual `@Mergifyio queue` worked, auto did not).
+#
+# The required-check list is duplicated across queue_conditions — YAML
+# anchors splice nested lists which Mergify rejects, so DRY isn't available.
 # Keep the list synced with `gh api repos/.../branches/main/protection`.
 #
-# Adding a new target branch (e.g. `develop`): replicate the 5 queue_rules
-# under `develop-*` names + 5 routing pull_request_rules with `base=develop`.
+# Where does `ecp/cross-pr-conflict` belong?
+# queue_conditions, NOT merge_conditions. Mergify's speculative trial
+# creates a fresh commit (PR diff + main tip) — ecp-pr-analyze.yml
+# triggers on `pull_request` events only, so the trial commit has no
+# cross-pr-conflict status reported against it. Anything required in
+# merge_conditions would thus block the trial indefinitely → dequeue
+# (PR #386 was the live repro). Keeping the check in queue_conditions
+# evaluates it on the PR HEAD where the status actually exists.
 
 queue_rules:
   - name: main-test-only
-    merge_conditions:
-      - base=main
-      - check-success=ecp/cross-pr-conflict
-    batch_size: 10
-    batch_max_wait_time: 30s
-
-  - name: main-parser-changes
-    merge_conditions:
-      - base=main
-      - check-success=ecp/cross-pr-conflict
-    batch_size: 1
-
-  - name: main-cli-changes
-    merge_conditions:
-      - base=main
-      - check-success=ecp/cross-pr-conflict
-    batch_size: 3
-    batch_max_wait_time: 2m
-
-  - name: main-docs-only
-    merge_conditions:
-      - base=main
-      - check-success=ecp/cross-pr-conflict
-    batch_size: 20
-    batch_max_wait_time: 10s
-
-  - name: main-default
-    merge_conditions:
-      - base=main
-      - check-success=ecp/cross-pr-conflict
-    batch_size: 2
-
-pull_request_rules:
-  - name: route area-test to main-test-only
-    conditions:
+    queue_conditions:
       - base=main
       - label=merge-queue
       - label=ecp:area-test
@@ -62,12 +39,14 @@ pull_request_rules:
       - check-success=Lint GitHub Actions workflows
       - check-success=CodeQL
       - check-success=dependency-review
-    actions:
-      queue:
-        name: main-test-only
+      - check-success=ecp/cross-pr-conflict
+    merge_conditions:
+      - base=main
+    batch_size: 10
+    batch_max_wait_time: 30s
 
-  - name: route area-parser to main-parser-changes
-    conditions:
+  - name: main-parser-changes
+    queue_conditions:
       - base=main
       - label=merge-queue
       - label=ecp:area-parser
@@ -77,12 +56,13 @@ pull_request_rules:
       - check-success=Lint GitHub Actions workflows
       - check-success=CodeQL
       - check-success=dependency-review
-    actions:
-      queue:
-        name: main-parser-changes
+      - check-success=ecp/cross-pr-conflict
+    merge_conditions:
+      - base=main
+    batch_size: 1
 
-  - name: route area-cli to main-cli-changes
-    conditions:
+  - name: main-cli-changes
+    queue_conditions:
       - base=main
       - label=merge-queue
       - label=ecp:area-cli
@@ -92,12 +72,14 @@ pull_request_rules:
       - check-success=Lint GitHub Actions workflows
       - check-success=CodeQL
       - check-success=dependency-review
-    actions:
-      queue:
-        name: main-cli-changes
+      - check-success=ecp/cross-pr-conflict
+    merge_conditions:
+      - base=main
+    batch_size: 3
+    batch_max_wait_time: 2m
 
-  - name: route area-docs to main-docs-only
-    conditions:
+  - name: main-docs-only
+    queue_conditions:
       - base=main
       - label=merge-queue
       - label=ecp:area-docs
@@ -107,12 +89,16 @@ pull_request_rules:
       - check-success=Lint GitHub Actions workflows
       - check-success=CodeQL
       - check-success=dependency-review
-    actions:
-      queue:
-        name: main-docs-only
+      - check-success=ecp/cross-pr-conflict
+    merge_conditions:
+      - base=main
+    batch_size: 20
+    batch_max_wait_time: 10s
 
-  - name: route default to main-default
-    conditions:
+  # Fallback queue — catches PRs with `merge-queue` label but no area label.
+  # Must come last; queue_conditions match via negation on the area-label set.
+  - name: main-default
+    queue_conditions:
       - base=main
       - label=merge-queue
       - -label~=^ecp:area-
@@ -122,14 +108,12 @@ pull_request_rules:
       - check-success=Lint GitHub Actions workflows
       - check-success=CodeQL
       - check-success=dependency-review
-    actions:
-      queue:
-        name: main-default
+      - check-success=ecp/cross-pr-conflict
+    merge_conditions:
+      - base=main
+    batch_size: 2
 
-  # Priority overrides removed in this PR.
-  # Modern Mergify exposes priority via `queue_rules.priority_rules` (per-queue
-  # nested rule list), not via `actions.queue.priority` on pull_request_rules.
-  # Implementing it cleanly requires duplicating priority_rules across all 5
-  # queue_rules (no shared anchor since Mergify YAML rejects nested-list
-  # splice). Tracked in FU-2026-05-23-037 — to be added when priority gets
-  # observed value (i.e. when same-area queue actually backs up).
+# Priority overrides: deferred to FU-2026-05-23-037.
+# Modern Mergify exposes priority via `queue_rules.priority_rules` (per-queue
+# nested rule list). Adding it cleanly requires duplicating priority_rules
+# across all 5 queue_rules. Implement when same-area queue actually backs up.