bazel/ci: Use workspace rather than action envs for fake scm revision (…

…#36298)

Signed-off-by: Ryan Northey <[email protected]>

.azure-pipelines/ci.yml

@@ -214,11 +214,10 @@ steps:
     # Any PR or CI run in envoy-presubmit uses the fake SCM hash
     if [[ "${{ variables['Build.Reason'] }}" == "PullRequest" || "${{ variables['Build.DefinitionName'] }}" == 'envoy-presubmit' ]]; then
         # sha1sum of `ENVOY_PULL_REQUEST`
-        BAZEL_FAKE_SCM_REVISION=e3b4a6e9570da15ac1caffdded17a8bebdc7dfc9
+        echo "e3b4a6e9570da15ac1caffdded17a8bebdc7dfc9" > .BAZEL_FAKE_SCM_REVISION
     fi
     echo "##vso[task.setvariable variable=BAZEL_BUILD_EXTRA_OPTIONS]${BAZEL_BUILD_EXTRA_OPTIONS}"
     echo "##vso[task.setvariable variable=BAZEL_EXTRA_TEST_OPTIONS]${BAZEL_EXTRA_TEST_OPTIONS}"
-    echo "##vso[task.setvariable variable=BAZEL_FAKE_SCM_REVISION]${BAZEL_FAKE_SCM_REVISION}"
     echo "##vso[task.setvariable variable=BAZEL_STARTUP_EXTRA_OPTIONS]${{ parameters.bazelStartupExtraOptions }}"
     echo "##vso[task.setvariable variable=CI_TARGET_BRANCH]${CI_TARGET_BRANCH}"
     echo "##vso[task.setvariable variable=ENVOY_DOCKER_BUILD_DIR]$(Build.StagingDirectory)"

.bazelrc

@@ -43,9 +43,6 @@ build:windows --action_env=PATH --host_action_env=PATH
 # Requires setting `BAZEL_VOLATILE_DIRTY` in the env.
 build --action_env=BAZEL_VOLATILE_DIRTY --host_action_env=BAZEL_VOLATILE_DIRTY
 
-# Prevent stamped caches from busting (eg in PRs)
-# Requires setting `BAZEL_FAKE_SCM_REVISION` in the env.
-build --action_env=BAZEL_FAKE_SCM_REVISION --host_action_env=BAZEL_FAKE_SCM_REVISION
 build --test_summary=terse
 
 build:docs-ci --action_env=DOCS_RST_CHECK=1 --host_action_env=DOCS_RST_CHECK=1

.github/workflows/_run.yml

@@ -250,6 +250,11 @@ jobs:
         passphrase-path: "${{ runner.temp }}/gpg-passphrase"
         configured-passphrase-path: /build/gpg-passphrase
 
+    - run: |
+        echo "e3b4a6e9570da15ac1caffdded17a8bebdc7dfc9" > .BAZEL_FAKE_SCM_REVISION
+      if: >-
+        ${{ fromJSON(inputs.request).request.pr == '' }}
+
     - uses: envoyproxy/toolshed/gh-actions/github/[email protected]
       name: Run CI ${{ inputs.command }} ${{ inputs.target }}
       with:
@@ -290,7 +295,6 @@ jobs:
           --config=remote-ci
           ${{ inputs.bazel-extra }}
           ${{ inputs.rbe == true && format('--jobs={0}', inputs.bazel-rbe-jobs) || '' }}
-        BAZEL_FAKE_SCM_REVISION: ${{ github.event_name == 'pull_request' && 'e3b4a6e9570da15ac1caffdded17a8bebdc7dfc9' || '' }}
         CI_BRANCH: >-
           ${{ inputs.trusted
               && format('refs/heads/{0}', fromJSON(inputs.request).request.target-branch)

bazel/get_workspace_status

@@ -29,7 +29,8 @@ then
     exit 0
 fi
 
-if [[ -n "$BAZEL_FAKE_SCM_REVISION" ]]; then
+if [[ -e ".BAZEL_FAKE_SCM_REVISION" ]]; then
+    BAZEL_FAKE_SCM_REVISION="$(cat .BAZEL_FAKE_SCM_REVISION)"
     echo "BUILD_SCM_REVISION $BAZEL_FAKE_SCM_REVISION"
     echo "ENVOY_BUILD_SCM_REVISION $BAZEL_FAKE_SCM_REVISION"
     echo "STABLE_BUILD_SCM_REVISION $BAZEL_FAKE_SCM_REVISION"

ci/run_envoy_docker.sh

@@ -131,7 +131,6 @@ docker run --rm \
        -e BAZEL_STARTUP_OPTIONS \
        -e BAZEL_BUILD_EXTRA_OPTIONS \
        -e BAZEL_EXTRA_TEST_OPTIONS \
-       -e BAZEL_FAKE_SCM_REVISION \
        -e BAZEL_REMOTE_CACHE \
        -e BAZEL_STARTUP_EXTRA_OPTIONS \
        -e CI_BRANCH \