From 63fe3778348945c1245b1f44c59d7614ed4e5739 Mon Sep 17 00:00:00 2001
From: Scott Suarez <ScottSuarez@google.com>
Date: Thu, 21 Sep 2023 14:25:53 -0700
Subject: [PATCH] Unblock Feature branch by no merging main if BASE_BRANCH !=
 main (#9040)

---
 .ci/gcb-community-checker.yml              | 25 +++++++++++-----------
 .ci/gcb-contributor-membership-checker.yml | 25 +++++++++++-----------
 2 files changed, 24 insertions(+), 26 deletions(-)

diff --git a/.ci/gcb-community-checker.yml b/.ci/gcb-community-checker.yml
index b7032b5c6148..08712995646b 100644
--- a/.ci/gcb-community-checker.yml
+++ b/.ci/gcb-community-checker.yml
@@ -22,13 +22,6 @@ steps:
       - user.name
       - "Modular Magician Diff Process"
 
-  # Fetch main (only if it's not already present)
-  - name: "gcr.io/cloud-builders/git"
-    args:
-      - fetch
-      - origin
-      - main
-
   # Display commit log for clarity
   - name: "gcr.io/cloud-builders/git"
     args:
@@ -36,18 +29,24 @@ steps:
       - "--oneline"
       - "-n 10"
 
-  # Find common ancestor commit and apply diff for the .ci folder
+  # Find common ancestor commit and apply diff for the .ci folder.
   - name: "gcr.io/cloud-builders/git"
     id: findMergeBase
     entrypoint: "bash"
     args:
       - "-c"
       - |
-        base_commit=$(git merge-base origin/main HEAD)
-        echo "Common ancestor commit: $base_commit"
-        git diff $base_commit origin/main -- .ci/
-        git diff $base_commit origin/main -- .ci/ > /workspace/ci.diff
-        git apply /workspace/ci.diff --allow-empty
+        git fetch origin main
+        if [ "$_BASE_BRANCH" != "main" ]; then
+          echo "Checking out .ci/ folder from main"
+          git checkout origin/main -- .ci/
+        else
+          base_commit=$(git merge-base origin/main HEAD)
+          echo "Common ancestor commit: $base_commit"
+          git diff $base_commit upstream/main -- .ci/
+          git diff $base_commit upstream/main -- .ci/ > /workspace/ci.diff
+          git apply ./ci.diff --allow-empty
+        fi
 
   - name: 'gcr.io/graphite-docker-images/go-plus'
     entrypoint: '/workspace/.ci/scripts/go-plus/magician/exec.sh'
diff --git a/.ci/gcb-contributor-membership-checker.yml b/.ci/gcb-contributor-membership-checker.yml
index d44ea5a4b4a2..3164a75a5cf8 100644
--- a/.ci/gcb-contributor-membership-checker.yml
+++ b/.ci/gcb-contributor-membership-checker.yml
@@ -22,13 +22,6 @@ steps:
       - user.name
       - "Modular Magician Diff Process"
 
-  # Fetch main (only if it's not already present)
-  - name: "gcr.io/cloud-builders/git"
-    args:
-      - fetch
-      - origin
-      - main
-
   # Display commit log for clarity
   - name: "gcr.io/cloud-builders/git"
     args:
@@ -36,18 +29,24 @@ steps:
       - "--oneline"
       - "-n 10"
 
-  # Find common ancestor commit and apply diff for the .ci folder
+  # Find common ancestor commit and apply diff for the .ci folder.
   - name: "gcr.io/cloud-builders/git"
     id: findMergeBase
     entrypoint: "bash"
     args:
       - "-c"
       - |
-        base_commit=$(git merge-base origin/main HEAD)
-        echo "Common ancestor commit: $base_commit"
-        git diff $base_commit origin/main -- .ci/
-        git diff $base_commit origin/main -- .ci/ > /workspace/ci.diff
-        git apply /workspace/ci.diff --allow-empty
+        git fetch origin main
+        if [ "$_BASE_BRANCH" != "main" ]; then
+          echo "Checking out .ci/ folder from main"
+          git checkout origin/main -- .ci/
+        else
+          base_commit=$(git merge-base origin/main HEAD)
+          echo "Common ancestor commit: $base_commit"
+          git diff $base_commit upstream/main -- .ci/
+          git diff $base_commit upstream/main -- .ci/ > /workspace/ci.diff
+          git apply ./ci.diff --allow-empty
+        fi
 
   - name: "gcr.io/graphite-docker-images/go-plus"
     entrypoint: "/workspace/.ci/scripts/go-plus/magician/exec.sh"