Post binary size reports in presubmits. (#8587)

* Post binary size reports in presubmits.

* Compare to the targeted branch head.

Author: granluo

.github/workflows/health_metrics.yml

@@ -28,7 +28,7 @@ jobs:
       performance_run_job: ${{ steps.check_files.outputs.performance_run_job }}
       remoteconfig_run_job: ${{ steps.check_files.outputs.remoteconfig_run_job }}
       storage_run_job: ${{ steps.check_files.outputs.storage_run_job }}
-      base_commit: ${{ steps.check_files.outputs.base_commit }}
+      target_branch_head: ${{ steps.check_files.outputs.target_branch_head }}
     runs-on: ubuntu-latest
     steps:
       - name: Checkout code
@@ -47,7 +47,7 @@ jobs:
   binary_size_metrics:
     needs: check
     # Prevent the job from being triggered in fork.
-    if: always() && github.repository == 'Firebase/firebase-ios-sdk' && github.event.pull_request.merged
+    if: always() && github.repository == 'Firebase/firebase-ios-sdk'
     runs-on: macos-11
     strategy:
       matrix:
@@ -82,7 +82,7 @@ jobs:
         ./scripts/health_metrics/create_binary_size_report.sh
       env:
         PULL_REQUEST_NUM: ${{ github.event.pull_request.number }}
-        BASE_COMMIT: ${{ github.event.pull_request.base.sha }}
+        BASE_COMMIT: ${{ needs.check.outputs.target_branch_head }}
         POSTSUBMIT: ${{ github.event.pull_request.merged }}
         SOURCE_BRANCH: ${{ github.base_ref }}
 
@@ -326,7 +326,7 @@ jobs:
       - name: Compare Diff and Post a Report
         if: github.event.pull_request.merged != true && github.event.action != 'closed' && github.event.pull_request.head.repo.full_name == github.repository
         env:
-          base_commit: ${{ github.event.pull_request.base.sha }}
+          base_commit: ${{ needs.check.outputs.target_branch_head }}
         run: |
           # Get Head commit of the branch, instead of a merge commit created by actions/checkout.
           if [ -d "${{steps.download.outputs.download-path}}" ]; then

scripts/health_metrics/get_updated_files.sh

@@ -17,15 +17,17 @@ set -ex
 # Updates in a pull request will generate a code coverage report in a PR.
 
 # Get most rescent ancestor commit.
-common_commit=$(git merge-base remotes/origin/${pr_branch} remotes/origin/master)
+common_commit=$(git merge-base remotes/origin/${pr_branch} remotes/origin/${GITHUB_BASE_REF})
+target_branch_head=$(git rev-parse remotes/origin/${GITHUB_BASE_REF})
 echo "The common commit is ${common_commit}."
-# Set base commit and this will be used to compare diffs of coverage to the current commit.
-echo "::set-output name=base_commit::${common_commit}"
+echo "The target branch head commit is ${target_branch_head}."
+# Set target branch head and this will be used to compare diffs of coverage to the current commit.
+echo "::set-output name=target_branch_head::${target_branch_head}"
 
 cd scripts/health_metrics/generate_code_coverage_report
 
-# List changed file from the base commit. This is generated by comparing the
-# head of the branch and the common commit from the master branch.
-git diff --name-only $common_commit remotes/origin/${pr_branch} > updated_files.txt
+# List changed file from the merged commit. This is generated by comparing the
+# merge commit to the head commit from the target branch.
+git diff --name-only remotes/origin/${GITHUB_BASE_REF} ${GITHUB_SHA} > updated_files.txt
 
 swift run UpdatedFilesCollector --changed-file-paths updated_files.txt --code-coverage-file-patterns ../code_coverage_file_list.json