fix: docs github mirror action (#1145)

.github/workflows/mirror_docs_repo.yml

@@ -20,4 +20,11 @@ jobs:
 
       - name: Push to branch
         run: |
-          ./scripts/git_subrepo.sh push docs --branch=main
+          # we push using git subrepo (https://github.com/ingydotnet/git-subrepo)
+          # with some logic to recover from squashed parent commits
+          SUBREPO_PATH=docs
+          # identify ourselves, needed to commit
+          git config --global user.email "tech@aztecprotocol.com"
+          git config --global user.name "AztecBot"
+          # push to subrepo, commit locally
+          ./scripts/git_subrepo.sh push $SUBREPO_PATH --branch=main

scripts/git_subrepo.sh

@@ -2,5 +2,42 @@
 set -eu
 
 SCRIPT_DIR=$(dirname "$(realpath "$0")")
-"$SCRIPT_DIR"/git-subrepo/lib/git-subrepo $@
+
+# Check for unstaged changes
+if ! git diff-index --quiet HEAD --; then
+    echo "Error: You have unstaged changes. Please commit or stash them before running git_subrepo.sh."
+    exit 1
+fi
+
+# git subrepo is quite nice, but has one flaw in our workflow:
+# We frequently squash commits in PRs, and we might update the .gitrepo file
+# with a parent commit that later does not exist. 
+# A backup heuristic is used to later find the squashed commit's parent
+# using the .gitrepo file's git history. This might be brittle 
+# in the face of e.g. a .gitrepo whitespace change, but it's a fallback, 
+# we only have this issue in master, and the file should only be edited
+# generally by subrepo commands.
+SUBREPO_PATH="${2:-}"
+if [ -d "$SUBREPO_PATH" ] ; then
+    # Read parent commit from .gitrepo file
+    parent_commit=$(awk -F'= ' '/parent =/{print $2}' $SUBREPO_PATH/.gitrepo)
+    # Check if the parent commit exists in this branch
+    if ! git branch --contains $parent_commit | grep -q '\*'; then
+        echo "Auto-fixing squashed parent in $SUBREPO_PATH/.gitrepo."
+
+        # Get the commit that last wrote to .gitrepo
+        last_commit=$(git log -1 --pretty=format:%H -- "$SUBREPO_PATH/.gitrepo")
+        # Get parent of the last commit
+        new_parent=$(git log --pretty=%P -n 1 $last_commit)
+
+        # Update parent in .gitrepo file using perl
+        perl -pi -e "s/${parent_commit}/${new_parent}/g" "$SUBREPO_PATH/.gitrepo"
+
+        # Commit this change
+        git add "$SUBREPO_PATH/.gitrepo"
+        # This commit should only go into squashed PRs
+        git commit -m "git_subrepo.sh: Fix parent in .gitrepo file."
+    fi
+fi
+"$SCRIPT_DIR"/git-subrepo/lib/git-subrepo -x $@