Change substitution to occur via environment variables. (#928)

* Change substitution to occur via environment variables.

* Fix missing suffix.

Author: jonsimantov

.github/workflows/integration_tests.yml

@@ -123,6 +123,9 @@ jobs:
     - name: Install python deps
       run: pip install -r scripts/gha/requirements.txt
     - id: matrix_config
+      env:
+        HEAD_REF: ${{github.event.pull_request.head.ref}}
+        BASE_REF: ${{github.event.pull_request.base.ref}}
       run: |
         # Log that we ran against a given packaged SDK.
         if [[ -n "${{ github.event.inputs.packaged_sdk_run_id }}" ]]; then
@@ -137,12 +140,12 @@ jobs:
         elif [[ "${{ steps.set_outputs.outputs.requested_tests }}" == "auto" ]]; then 
           # auto-diff only apply when running in a PR. 
           # diff against the PR's base. "git merge-base main branch_name" will give the common ancestor of both branches.
-          MERGE_BASE=$(git merge-base origin/${{github.event.pull_request.head.ref}} origin/${{github.event.pull_request.base.ref}} || true)
+          MERGE_BASE=$(git merge-base "origin/${HEAD_REF}" "origin/${BASE_REF}" || true)
           # If origin/<branch> is no longer valid, then just run all tests.
           if [[ -n "${MERGE_BASE}" ]]; then
-            echo "::warning ::Auto-diff origin/${{github.event.pull_request.head.ref}}..${MERGE_BASE}"
-            git diff --name-only origin/${{github.event.pull_request.head.ref}}..${MERGE_BASE}
-            TEST_MATRIX_PARAM="--auto_diff origin/${{github.event.pull_request.head.ref}}..${MERGE_BASE}"
+            echo "::warning ::Auto-diff origin/${HEAD_REF}..${MERGE_BASE}"
+            git diff --name-only "origin/${HEAD_REF}..${MERGE_BASE}"
+            TEST_MATRIX_PARAM="--auto_diff origin/${HEAD_REF}..${MERGE_BASE}"
           fi
         fi
         # To feed input into the job matrix, we first need to convert to a JSON

scripts/gha/it_workflow.py

@@ -71,6 +71,7 @@
 _COMMENT_IDENTIFIER_DASHBOARD = "build-dashboard-comment"
 _COMMENT_DASHBOARD_START = f'\r\n<hidden value="{_COMMENT_IDENTIFIER_DASHBOARD}-start"></hidden>\r\n'
 _COMMENT_DASHBOARD_END = f'\r\n<hidden value="{_COMMENT_IDENTIFIER_DASHBOARD}-end"></hidden>\r\n'
+_COMMENT_SUFFIX = f'\n<hidden value="{_COMMENT_IDENTIFIER}"></hidden>'
 
 _LOG_ARTIFACT_NAME = "log-artifact"
 _LOG_OUTPUT_DIR = "test_results"
@@ -227,11 +228,18 @@ def _get_issue_number(token, title, label):
     if issue["title"] == title:
       return issue["number"]
 
-  return firebase_github.create_issue(token, title, label, _COMMENT_SUFFIX)["number"]
+  empty_comment = (" " +
+                   _COMMENT_DASHBOARD_START + " " +
+                   _COMMENT_DASHBOARD_END + " " +
+                   _COMMENT_HIDDEN_DIVIDER + " " +
+                   _COMMENT_HIDDEN_DIVIDER + " " +
+                   _COMMENT_HIDDEN_DIVIDER + " "
+                   )
+  return firebase_github.create_issue(token, title, label, empty_comment)["number"]
 
 
 def _update_comment(token, issue_number, comment):
-  comment_id = _get_comment_id(token, issue_number, _COMMENT_SUFFIX)
+  comment_id = _get_comment_id(token, issue_number, _COMMENT_HIDDEN_DIVIDER)
   if not comment_id:
     firebase_github.add_comment(token, issue_number, comment)
   else: