From 39a8c653157758803dca6de50a995c036d51bd83 Mon Sep 17 00:00:00 2001
From: hill <hill@hilll.dev>
Date: Tue, 29 Sep 2026 13:45:20 +0200
Subject: [PATCH] Sync upstream even when main was deleted

Deleting main after merging a sync PR (GitHub offers it) made every later run fail at checkout, so no sync PR opened after Sep 27. The job now checks out the default branch, recreates main from upstream when it is missing, and still refuses to overwrite a main with commits upstream lacks. The PR text asks to keep main.
---
 .github/workflows/sync_upstream.yml | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/.github/workflows/sync_upstream.yml b/.github/workflows/sync_upstream.yml
index 10b6547cc4ce..fe00e41f7595 100644
--- a/.github/workflows/sync_upstream.yml
+++ b/.github/workflows/sync_upstream.yml
@@ -28,16 +28,19 @@ jobs:
 
       - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
         with:
-          ref: main
           fetch-depth: 0
           token: ${{ secrets.UPSTREAM_SYNC_TOKEN }}
 
       - name: Fast-forward main to upstream
         run: |
           git fetch --no-tags https://github.com/ankidroid/Anki-Android.git main:refs/remotes/upstream/main
-          if ! git merge-base --is-ancestor HEAD refs/remotes/upstream/main; then
-            echo "::error::main has commits that are not upstream's. It must stay a mirror of ankidroid/Anki-Android main."
-            exit 1
+          if git fetch --no-tags origin main:refs/remotes/origin/main; then
+            if ! git merge-base --is-ancestor refs/remotes/origin/main refs/remotes/upstream/main; then
+              echo "::error::main has commits that are not upstream's. It must stay a mirror of ankidroid/Anki-Android main."
+              exit 1
+            fi
+          else
+            echo "::warning::main was missing (deleted after a merge?); recreating it from upstream"
           fi
           git push origin refs/remotes/upstream/main:refs/heads/main
 
@@ -60,6 +63,6 @@ jobs:
             --title "Merge upstream AnkiDroid" \
             --body "$behind new commits from ankidroid/Anki-Android main.
 
-          Merge with a merge commit, never squash or rebase, so ankiquest keeps upstream's history.
+          Merge with a merge commit, never squash or rebase, so ankiquest keeps upstream's history. Keep the main branch after merging: it mirrors upstream.
 
           If this conflicts, merge main into a branch from ankiquest, resolve there, and merge that branch instead. Never commit to main: it mirrors upstream."