Cancel only superseded PR runs in CI

A CI or compatibility run is now cancelled only when a newer push to
the same pull request replaces it. Push, dispatch and scheduled runs
always finish, so a manually dispatched run on the v5 base branch (its
only CI verdict, since push CI runs on main alone) is no longer killed
by a later dispatch or by the non-main cancel rule, and main keeps
finishing its rust-cache saves.

CI now groups PR runs by PR number, like the compatibility workflows
already do.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01AfGnDQMy2FvpExneXmR1qp

Author: claude

.github/workflows/bun-compatibility.yml

@@ -95,11 +95,11 @@ on:
 permissions:
   contents: read
 
-# Supersede stale PR runs. The `main` guard is load-bearing: main runs are the
-# ONLY rust-cache writers (save-if), so they must never be cancelled mid-save.
+# Supersede stale PR runs only: main runs are the ONLY rust-cache writers
+# (save-if), so push, dispatch and schedule runs are never cancelled mid-save.
 concurrency:
   group: bun-patch-${{ github.event.pull_request.number || github.ref }}
-  cancel-in-progress: ${{ github.ref != 'refs/heads/main' }}
+  cancel-in-progress: ${{ github.event_name == 'pull_request' }}
 
 env:
   CARGO_PROFILE_DEV_DEBUG: '0'

.github/workflows/ci.yml

@@ -17,12 +17,13 @@ on:
 permissions:
   contents: read
 
-# Supersede stale runs on force-push / rapid PR updates. The `main` guard is
-# load-bearing: main runs are the ONLY rust-cache writers (save-if), so they
-# must never be cancelled mid-save.
+# A newer push to the same PR supersedes its older run; nothing else is
+# cancelled. Push, dispatch and schedule runs always finish: main runs are
+# the ONLY rust-cache writers (save-if) and must not die mid-save, and a
+# dispatched base-branch run is the base's only CI verdict.
 concurrency:
-  group: ci-${{ github.ref }}
-  cancel-in-progress: ${{ github.ref != 'refs/heads/main' }}
+  group: ci-${{ github.event.pull_request.number || github.ref }}
+  cancel-in-progress: ${{ github.event_name == 'pull_request' }}
 
 jobs:
   clippy:

.github/workflows/go-compatibility.yml

@@ -30,7 +30,7 @@ permissions:
 
 concurrency:
   group: go-compat-${{ github.event.pull_request.number || github.ref }}
-  cancel-in-progress: true
+  cancel-in-progress: ${{ github.event_name == 'pull_request' }}
 
 env:
   SOCKET_NO_CONFIG: '1'

.github/workflows/pdm-compatibility.yml

@@ -48,7 +48,7 @@ permissions:
 
 concurrency:
   group: pdm-compat-${{ github.event.pull_request.number || github.ref }}
-  cancel-in-progress: true
+  cancel-in-progress: ${{ github.event_name == 'pull_request' }}
 
 env:
   SOCKET_NO_CONFIG: '1'

.github/workflows/poetry-compatibility.yml

@@ -40,7 +40,7 @@ permissions:
 
 concurrency:
   group: poetry-compat-${{ github.event.pull_request.number || github.ref }}
-  cancel-in-progress: true
+  cancel-in-progress: ${{ github.event_name == 'pull_request' }}
 
 env:
   SOCKET_NO_CONFIG: '1'

.github/workflows/vlt-compatibility.yml

@@ -117,11 +117,11 @@ on:
 permissions:
   contents: read
 
-# Supersede stale PR runs; main runs are the only rust-cache writers, so they
-# are never cancelled mid-save.
+# Supersede stale PR runs only: main runs are the only rust-cache writers, so
+# push, dispatch and schedule runs are never cancelled mid-save.
 concurrency:
   group: vlt-compat-${{ github.event.pull_request.number || github.ref }}
-  cancel-in-progress: ${{ github.ref != 'refs/heads/main' }}
+  cancel-in-progress: ${{ github.event_name == 'pull_request' }}
 
 env:
   CARGO_PROFILE_DEV_DEBUG: '0'