Wait for the PR's Deps Cache in clang-tidy When deps/ Changes (#16374)

* Wait for the PR's Deps Cache in clang-tidy When deps/ Changes

* Fail the clang-tidy Deps Wait When Listing Caches Keeps Failing

* Wait for Deps Through ci_deps_cache.sh in clang-tidy

Reuse the macOS deps wait for Linux: the job names, workflow and cache
ref are passed in, and a new 'own' mode waits for the PR's own build
when it changes deps/. A PR that keeps deps/ now waits for a running base
build with the same deps, and warns when it falls back to older ones. The
wait ends as soon as the deps job fails.

.github/workflows/clang_tidy.yml

@@ -16,6 +16,15 @@ on:
 
 permissions:
   contents: read
+  # Listing caches and builds while waiting for a deps cache.
+  actions: read
+
+# Read by scripts/ci_deps_cache.sh.
+env:
+  REPO: ${{ github.repository }}
+  WORKFLOW: build_all.yml
+  BASE_REF: ${{ github.base_ref }}
+  JOB: build_linux (${{ vars.SELF_HOSTED && 'orca-lnx-server' || 'ubuntu-24.04' }})
 
 concurrency:
   group: ${{ github.workflow }}-${{ github.event.pull_request.number }}
@@ -35,7 +44,7 @@ jobs:
           # The PR merge commit plus its first parent, the base it is diffed against.
           fetch-depth: 2
 
-      - name: Look for changed C++ files
+      - name: Look for changed files
         id: changes
         run: |
           if git -c core.quotePath=false diff --name-only HEAD^1 -- src tests | grep -qE '\.(cpp|cc|cxx|hpp|h|hxx)$'; then
@@ -43,18 +52,75 @@ jobs:
           else
             echo "No C++ changes under src/ or tests/."
           fi
+          if ! git diff --quiet HEAD^1 -- deps; then
+            echo "deps=true" >> "$GITHUB_OUTPUT"
+          fi
+          echo "deps-key=linux-clang-cache-orcaslicer_deps-build-${{ hashFiles('deps/**') }}" >> "$GITHUB_OUTPUT"
 
-      # Parsing needs the dependency headers, not a build of this PR's deps/, so
-      # a PR that changes deps/ falls back to the newest cache main has.
+      # Parsing needs the dependency headers, not a build of this PR's deps/.
+      # Without an exact match the job waits for the build that saves it: this
+      # PR's own when it changes deps/, otherwise a running push build of the
+      # base branch with the same deps. With neither, a PR that keeps deps/
+      # falls back to the newest cache.
       - name: Restore cached deps
+        id: deps_cache
         if: steps.changes.outputs.cpp == 'true'
         uses: actions/cache/restore@v6
         with:
           path: ${{ github.workspace }}/deps/build/OrcaSlicer_dep
-          key: linux-clang-cache-orcaslicer_deps-build-${{ hashFiles('deps/**') }}
+          key: ${{ steps.changes.outputs.deps-key }}
+
+      - name: Look for a build to wait for
+        id: wait_check
+        if: steps.changes.outputs.cpp == 'true' && steps.deps_cache.outputs.cache-hit != 'true'
+        env:
+          GH_TOKEN: ${{ github.token }}
+          HEAD_SHA: ${{ github.event.pull_request.head.sha }}
+        run: bash scripts/ci_deps_cache.sh ${{ steps.changes.outputs.deps == 'true' && 'own' || 'check' }}
+
+      # Linux Build Deps takes about 35 minutes on GitHub-hosted runners. The
+      # wait ends early when the deps job fails.
+      - name: Wait for the deps cache
+        if: steps.wait_check.outputs.wait-for != ''
+        timeout-minutes: 100
+        env:
+          GH_TOKEN: ${{ github.token }}
+          KEY: ${{ steps.changes.outputs.deps-key }}
+          CACHE_REF: ${{ steps.changes.outputs.deps == 'true' && github.ref || format('refs/heads/{0}', github.base_ref) }}
+          KEY_INPUTS: ${{ steps.wait_check.outputs.key-inputs }}
+          WAIT_FOR: ${{ steps.wait_check.outputs.wait-for }}
+          WAIT_SINCE: ${{ steps.wait_check.outputs.wait-since }}
+          WAIT_MINUTES: 90
+        run: bash scripts/ci_deps_cache.sh wait
+
+      - name: Restore the deps cache after waiting
+        id: waited_cache
+        if: steps.wait_check.outputs.wait-for != ''
+        uses: actions/cache/restore@v6
+        with:
+          path: ${{ github.workspace }}/deps/build/OrcaSlicer_dep
+          key: ${{ steps.changes.outputs.deps-key }}
+
+      - name: Fail without this PR's deps cache
+        if: steps.changes.outputs.deps == 'true' && steps.wait_check.outcome == 'success' && steps.waited_cache.outputs.cache-hit != 'true'
+        run: |
+          echo "::error::No deps cache ${{ steps.changes.outputs.deps-key }}. Check this PR's Linux Build Deps job, then rerun clang-tidy."
+          exit 1
+
+      - name: Restore the newest cached deps
+        id: newest_cache
+        if: steps.changes.outputs.deps != 'true' && steps.wait_check.outcome == 'success' && steps.waited_cache.outputs.cache-hit != 'true'
+        uses: actions/cache/restore@v6
+        with:
+          path: ${{ github.workspace }}/deps/build/OrcaSlicer_dep
+          key: ${{ steps.changes.outputs.deps-key }}
           restore-keys: linux-clang-cache-orcaslicer_deps-build-
           fail-on-cache-miss: true
 
+      - name: Warn about older deps
+        if: steps.newest_cache.outcome == 'success' && steps.newest_cache.outputs.cache-hit != 'true'
+        run: echo "::warning title=Older deps::No cache matches this PR's deps/, so clang-tidy parsed against ${{ steps.newest_cache.outputs.cache-matched-key }}. If it reports errors in code that uses a dependency, rerun clang-tidy once the base branch's Build all has saved the new deps."
+
       - name: Apt-Install Dependencies
         if: steps.changes.outputs.cpp == 'true' && !vars.SELF_HOSTED
         uses: ./.github/actions/apt-install-deps

scripts/ci_deps_cache.sh

@@ -1,21 +1,27 @@
 #!/usr/bin/env bash
-# Lets a pull request's macOS deps build wait for a push build of the base
-# branch that builds the same deps, from a Linux job. `check` runs after a cache
-# miss and names a queued or running base build with the same deps/ and .github/
-# to wait for, unless the pull request changes either. `wait` waits until that
-# build saves KEY. actions/cache then confirms the entry can be restored.
+# Lets a pull request's macOS deps build, or its clang-tidy job, wait for a
+# build that saves the deps cache it needs, from a Linux job. `check` runs after
+# a cache miss and names a queued or running push build of the base branch with
+# the same deps/ and .github/ to wait for, unless the pull request changes either.
+# `own` names the pull request's own build instead, for clang-tidy when the pull
+# request changes deps/. `wait` waits until that build saves KEY under CACHE_REF,
+# or its deps job fails. actions/cache then confirms the entry can be restored.
 #
-# Environment: GH_TOKEN, REPO, WORKFLOW_REF and BASE_REF, plus KEY_INPUTS,
-# WAIT_FOR, WAIT_SINCE, WAIT_MINUTES, KEY and ARCH for `wait`.
+# Environment: GH_TOKEN, REPO, WORKFLOW_REF (or WORKFLOW, the build workflow's
+# file name) and BASE_REF, plus HEAD_SHA for `own`, and KEY_INPUTS, WAIT_FOR,
+# WAIT_SINCE, WAIT_MINUTES, KEY, CACHE_REF (default the base branch) and ARCH
+# (or JOB, the matrix job's name) for `wait`.
 # Writes key-inputs, wait-for and wait-since to $GITHUB_OUTPUT.
 set -uo pipefail
 
-workflow=${WORKFLOW_REF%%@*}
-workflow=${workflow##*/}
+workflow=${WORKFLOW_REF:-}
+workflow=${workflow%%@*}
+workflow=${WORKFLOW:-${workflow##*/}}
 
 # Must match the job names in build_all.yml, build_check_cache.yml and build_deps.yml.
-check_job_name="build_macos_arch (${ARCH:-}) / Check Cache"
-deps_job_name="build_macos_arch (${ARCH:-}) / Build Deps / Build Deps"
+job=${JOB:-build_macos_arch (${ARCH:-})}
+check_job_name="$job / Check Cache"
+deps_job_name="$job / Build Deps / Build Deps"
 
 out() { echo "$1" >> "${GITHUB_OUTPUT:-/dev/stdout}"; }
 
@@ -63,8 +69,27 @@ check() {
   fi
 }
 
+own() {
+  out "key-inputs=$(local_key_inputs HEAD)"
+  local id
+  # The build can be created a moment after this job.
+  for _ in 1 2 3 4 5; do
+    id=$(gh api -X GET "repos/$REPO/actions/workflows/$workflow/runs" \
+      -f head_sha="$HEAD_SHA" -f event=pull_request -f per_page=1 --jq '.workflow_runs[0].id // empty' < /dev/null)
+    [ -n "$id" ] && break
+    sleep 30
+  done
+  if [ -n "$id" ]; then
+    echo "Waiting for the deps cache of build $id of this pull request."
+    out "wait-for=$id"
+    out "wait-since=$(date +%s)"
+  else
+    echo "No build of this pull request is building its deps."
+  fi
+}
+
 key_saved() {
-  gh cache list -R "$REPO" --ref "refs/heads/$BASE_REF" --key "$KEY" --json key < /dev/null \
+  gh cache list -R "$REPO" --ref "${CACHE_REF:-refs/heads/$BASE_REF}" --key "$KEY" --json key < /dev/null \
     | jq -e --arg key "$KEY" 'any(.[]; .key == $key)' > /dev/null
 }
 
@@ -87,11 +112,11 @@ wait_for() {
           key_saved && { echo "Found $KEY."; return; }
           sleep 20
         done
-        echo "Build $id of $BASE_REF finished its deps without saving $KEY."
+        echo "Build $id finished its deps without saving $KEY."
         return ;;
       "completed cancelled") ;;
       completed*)
-        echo "The deps job of build $id of $BASE_REF did not succeed."
+        echo "The deps job of build $id did not succeed."
         return ;;
       # The deps job exists only once the build's cache check has succeeded.
       "")
@@ -100,7 +125,7 @@ wait_for() {
           completed*)
             check=$(jq -r --arg name "$check_job_name" 'first(.jobs[] | select(.name == $name) | .conclusion) // ""' <<< "$jobs")
             if [ -z "$warned" ] && { [ -z "$check" ] || [ "$check" = success ]; }; then
-              echo "::warning title=Deps wait::Build $id of $BASE_REF has no job named \"$deps_job_name\". If the build jobs were renamed, update scripts/ci_deps_cache.sh. This does not affect this pull request."
+              echo "::warning title=Deps wait::Build $id has no job named \"$deps_job_name\". If the build jobs were renamed, update scripts/ci_deps_cache.sh. This does not affect this pull request."
               warned=1
             fi ;;
           *)
@@ -118,11 +143,12 @@ wait_for() {
     seen="$seen $id"
     echo "Following build $id of $BASE_REF."
   done
-  echo "No build of $BASE_REF saved $KEY."
+  echo "No build saved $KEY."
 }
 
 case "${1:-}" in
   check) check ;;
+  own) own ;;
   wait) wait_for ;;
-  *) echo "usage: $0 check|wait" >&2; exit 2 ;;
+  *) echo "usage: $0 check|own|wait" >&2; exit 2 ;;
 esac