chore: add monorepo migration script

monorepo-migration/migrate.sh

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+#!/bin/bash
+# Copyright 2026 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+
+# Exit on error
+set -e
+
+# Function to check if a command exists
+check_command() {
+    if ! command -v "$1" >/dev/null 2>&1; then
+        echo "Error: $1 is not installed or not in PATH." >&2
+        exit 1
+    fi
+}
+
+# Check for necessary CLI binaries
+check_command git
+check_command python3
+check_command mvn
+
+# Configuration
+MONOREPO_URL="https://github.com/googleapis/google-cloud-java"
+SOURCE_REPO_URL="${SOURCE_REPO_URL:-https://github.com/googleapis/java-logging}"
+CODEOWNER="${CODEOWNER:-}"
+
+# Derive names from URLs to avoid duplication
+SOURCE_REPO_NAME="${SOURCE_REPO_URL##*/}"
+MONOREPO_NAME="${MONOREPO_URL##*/}"
+
+# Use a temporary working directory sibling to the current monorepo
+WORKING_DIR="../../migration-work"
+SOURCE_DIR="$WORKING_DIR/$SOURCE_REPO_NAME-source"
+TARGET_DIR="$WORKING_DIR/$MONOREPO_NAME-target"
+
+# Get absolute path to the transformation script before any cd
+TRANSFORM_SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
+TRANSFORM_SCRIPT="$TRANSFORM_SCRIPT_DIR/transform_workflow.py"
+MODERNIZE_POM_SCRIPT="$TRANSFORM_SCRIPT_DIR/modernize_pom.py"
+UPDATE_ROOT_POM_SCRIPT="$TRANSFORM_SCRIPT_DIR/update_root_pom.py"
+
+echo "Starting migration using git read-tree with isolated clones..."
+
+# 0. Create working directory
+mkdir -p "$WORKING_DIR"
+
+# 1. Clone the source repository
+if [ ! -d "$SOURCE_DIR" ]; then
+    echo "Cloning source repo: $SOURCE_REPO_URL into $SOURCE_DIR"
+    git clone "$SOURCE_REPO_URL" "$SOURCE_DIR"
+else
+    echo "Source directory $SOURCE_DIR already exists. Ensuring it is clean and up-to-date..."
+    cd "$SOURCE_DIR"
+    git fetch origin
+    git checkout -f main
+    git reset --hard origin/main
+    git clean -fd
+    cd - > /dev/null
+fi
+
+# 2. Clone the target monorepo (the "isolated clone")
+if [ ! -d "$TARGET_DIR" ]; then
+    echo "Cloning target monorepo: $MONOREPO_URL into $TARGET_DIR"
+    git clone "$MONOREPO_URL" "$TARGET_DIR"
+else
+    echo "Target directory $TARGET_DIR already exists. Ensuring it is clean and up-to-date..."
+    cd "$TARGET_DIR"
+    git fetch origin
+    git checkout -f main
+    git reset --hard origin/main
+    git clean -fd
+    cd - > /dev/null
+fi
+
+cd "$TARGET_DIR"
+
+# Ensure we are on a clean main branch in the target clone
+echo "Ensuring clean state in target monorepo..."
+git fetch origin
+git reset --hard HEAD
+git clean -fd
+git checkout -f main
+git reset --hard origin/main
+git clean -fdx
+
+# Check if the repository is already migrated
+if [ -d "$SOURCE_REPO_NAME" ]; then
+    echo "Error: Directory $SOURCE_REPO_NAME already exists in the monorepo." >&2
+    echo "This repository seems to have already been migrated." >&2
+    exit 1
+fi
+
+
+# 2.5 Create a new feature branch for the migration
+BRANCH_NAME="migrate-$SOURCE_REPO_NAME"
+echo "Creating feature branch: $BRANCH_NAME"
+if git rev-parse --verify "$BRANCH_NAME" >/dev/null 2>&1; then
+    git branch -D "$BRANCH_NAME"
+fi
+git checkout -b "$BRANCH_NAME"
+
+# 3. Add the source repo as a remote
+echo "Adding remote for $SOURCE_REPO_NAME: $SOURCE_DIR"
+if git remote | grep -q "^$SOURCE_REPO_NAME$"; then
+    git remote remove "$SOURCE_REPO_NAME"
+fi
+git remote add "$SOURCE_REPO_NAME" "../$SOURCE_REPO_NAME-source"
+
+# 4. Fetch the source repo
+echo "Fetching $SOURCE_REPO_NAME..."
+git fetch "$SOURCE_REPO_NAME"
+
+# 5. Merge the histories using 'ours' strategy to keep monorepo content
+echo "Merging histories (strategy: ours)..."
+git merge --allow-unrelated-histories --no-ff "$SOURCE_REPO_NAME/main" -s ours --no-commit -m "chore($SOURCE_REPO_NAME): migrate $SOURCE_REPO_NAME into monorepo"
+
+# 6. Read the tree from the source repo into the desired subdirectory
+echo "Reading tree into prefix $SOURCE_REPO_NAME/..."
+git read-tree --prefix="$SOURCE_REPO_NAME/" -u "$SOURCE_REPO_NAME/main"
+
+# 6.5 Remove common files from the root of the migrated library
+echo "Removing common files from the root of $SOURCE_REPO_NAME/..."
+rm -f "$SOURCE_REPO_NAME/.gitignore"
+rm -f "$SOURCE_REPO_NAME/renovate.json"
+rm -f "$SOURCE_REPO_NAME/LICENSE"
+rm -f "$SOURCE_REPO_NAME/java.header"
+rm -f "$SOURCE_REPO_NAME/license-checks.xml"
+find "$SOURCE_REPO_NAME" -maxdepth 1 -name "*.md" ! -name "CHANGELOG.md" ! -name "README.md" -delete
+
+# 7. Commit the migration
+echo "Committing migration..."
+git commit -n --no-gpg-sign -m "chore($SOURCE_REPO_NAME): migrate $SOURCE_REPO_NAME into monorepo"
+
+# 7.1 Update CODEOWNERS
+if [ -n "$CODEOWNER" ]; then
+    echo "Updating .github/CODEOWNERS..."
+    mkdir -p .github
+    echo "/$SOURCE_REPO_NAME/ $CODEOWNER @googleapis/cloud-java-team-teamsync" >> .github/CODEOWNERS
+
+    echo "Committing CODEOWNERS update..."
+    git add .github/CODEOWNERS
+    git commit -n --no-gpg-sign -m "chore($SOURCE_REPO_NAME): add code owners for $SOURCE_REPO_NAME"
+fi
+
+# 7.2 Update root pom.xml modules
+echo "Updating root pom.xml modules..."
+python3 "$UPDATE_ROOT_POM_SCRIPT" "pom.xml" "$SOURCE_REPO_NAME"
+
+echo "Committing root pom.xml modules update..."
+git add pom.xml
+git commit -n --no-gpg-sign -m "chore($SOURCE_REPO_NAME): add module to root pom.xml"
+
+
+# 7.5 Migrate GitHub Actions workflows
+echo "Checking for GitHub Actions workflows..."
+if [ -d "$SOURCE_REPO_NAME/.github/workflows" ]; then
+    echo "Migrating workflows to root .github/workflows/..."
+    mkdir -p .github/workflows
+
+    for workflow in "$SOURCE_REPO_NAME/.github/workflows/"*; do
+        if [ -f "$workflow" ]; then
+            filename=$(basename "$workflow")
+
+            # Skip redundant workflows as requested by user
+            case "$filename" in
+                "hermetic_library_generation.yaml" | "update_generation_config.yaml" | \
+                "approve-readme.yaml" | "auto-release.yaml" | "renovate_config_check.yaml" | \
+                "samples.yaml" | "unmanaged_dependency_check.yaml")
+                    echo "Skipping redundant workflow: $filename"
+                    continue
+                    ;;
+            esac
+
+            new_filename="${SOURCE_REPO_NAME}-${filename}"
+            target_path=".github/workflows/$new_filename"
+
+            echo "Migrating and adapting $filename to $target_path"
+            python3 "$TRANSFORM_SCRIPT" "$SOURCE_REPO_NAME" < "$workflow" > "$target_path"
+        fi
+    done
+
+    # Cleanup empty .github directory if it exists
+    rm -rf "$SOURCE_REPO_NAME/.github"
+
+    echo "Committing workflow migration..."
+    git add .github/workflows
+    git commit -n --no-gpg-sign -m "chore($SOURCE_REPO_NAME): migrate and adapt GitHub Actions workflows"
+fi
+
+# 7.6 Update generation_config.yaml
+echo "Updating generation_config.yaml..."
+SOURCE_CONFIG="$SOURCE_REPO_NAME/generation_config.yaml"
+if [ -f "$SOURCE_CONFIG" ]; then
+    # Extract the library entry (starts with - api_shortname)
+    # This assumes the source config only has one library or we want the first one
+    ENTRY=$(awk '/^  - api_shortname:/{flag=1; print $0; next} /^  - / && flag{flag=0} flag' "$SOURCE_CONFIG")
+
+    # Simple cleanup: remove repo and repo_short if they exist
+    # Adjust indentation to match monorepo (0 spaces for -)
+    CLEAN_ENTRY=$(echo "$ENTRY" | sed '/repo:/d' | sed '/repo_short:/d' | sed 's/^  //')
+
+    # Append to target generation_config.yaml
+    echo "" >> generation_config.yaml
+    echo "$CLEAN_ENTRY" >> generation_config.yaml
+
+    echo "Committing generation_config.yaml update..."
+    git add generation_config.yaml
+    git commit -n --no-gpg-sign -m "chore($SOURCE_REPO_NAME): add library to generation_config.yaml"
+fi
+
+# 7.7 Consolidate versions.txt
+echo "Consolidating versions.txt..."
+SOURCE_VERSIONS="$SOURCE_REPO_NAME/versions.txt"
+if [ -f "$SOURCE_VERSIONS" ]; then
+    # Append data lines only to root versions.txt (exclude comments/headers)
+    grep "^[a-zA-Z0-9]" "$SOURCE_VERSIONS" >> versions.txt
+
+    # Remove the migrated subdirectory's versions.txt
+    rm "$SOURCE_VERSIONS"
+
+    echo "Committing versions.txt update..."
+    git add versions.txt "$SOURCE_VERSIONS"
+    git commit -n --no-gpg-sign -m "chore($SOURCE_REPO_NAME): consolidate versions.txt into root"
+fi
+
+# 7.8 Fix copyright headers in Java files
+echo "Fixing copyright headers in Java files..."
+find "$SOURCE_REPO_NAME" -name "*.java" -exec python3 -c "import sys, re; p = sys.argv[1]; c = open(p).read(); new_c = re.sub(r'Copyright \d{4} Google (Inc\.|LLC)', 'Copyright 2026 Google LLC', c); open(p, 'w').write(new_c)" {} \;
+
+echo "Committing copyright header fixes..."
+git add "$SOURCE_REPO_NAME"
+git commit -n --no-gpg-sign -m "chore($SOURCE_REPO_NAME): update copyright headers to 2026 Google LLC"
+
+# 7.9 Modernize root pom.xml
+echo "Modernizing root pom.xml..."
+PARENT_VERSION=$(grep -m 1 "<version>.*{x-version-update:google-cloud-java:current}" google-cloud-jar-parent/pom.xml | sed -E 's/.*<version>(.*)<\/version>.*/\1/')
+python3 "$MODERNIZE_POM_SCRIPT" "$SOURCE_REPO_NAME/pom.xml" "$PARENT_VERSION"
+
+echo "Committing root pom.xml modernization..."
+git add "$SOURCE_REPO_NAME/pom.xml"
+git commit -n --no-gpg-sign -m "chore($SOURCE_REPO_NAME): modernize root pom.xml"
+
+# 7.10 Verify compilation
+echo "Verifying compilation..."
+(cd "$SOURCE_REPO_NAME" && mvn compile -DskipTests -T 1C)
+
+# 8. Cleanup
+echo "Cleaning up temporary source clone..."
+rm -rf "$SOURCE_DIR"
+
+echo "Migration complete!"
+echo "The migrated codebase is available in: $TARGET_DIR"
+echo "You are on the $BRANCH_NAME branch in that clone."

monorepo-migration/modernize_pom.py

@@ -0,0 +1,116 @@
+# Copyright 2026 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import sys
+import re
+
+def modernize_pom(file_path, parent_version):
+    with open(file_path, 'r') as f:
+        lines = f.readlines()
+
+    new_lines = []
+    in_parent = False
+    in_dep_mgmt = False
+    in_dependencies = False
+    in_dependency = False
+    in_reporting = False
+    current_dependency_lines = []
+    has_x_version_update = False
+
+    for line in lines:
+        # Parent section modernization
+        if '<parent>' in line and not in_parent:
+            in_parent = True
+            indent = line[:line.find('<')]
+            new_lines.append(f"{indent}<parent>\n")
+            new_lines.append(f"{indent}  <groupId>com.google.cloud</groupId>\n")
+            new_lines.append(f"{indent}  <artifactId>google-cloud-jar-parent</artifactId>\n")
+            new_lines.append(f"{indent}  <version>{parent_version}</version><!-- {{x-version-update:google-cloud-java:current}} -->\n")
+            new_lines.append(f"{indent}  <relativePath>../google-cloud-jar-parent/pom.xml</relativePath>\n")
+            continue
+        if '</parent>' in line and in_parent:
+            in_parent = False
+            new_lines.append(line)
+            continue
+        if in_parent:
+            continue # skip original parent content
+
+        # Dependency Management pruning
+        if '<dependencyManagement>' in line:
+            in_dep_mgmt = True
+            new_lines.append(line)
+            continue
+        if '</dependencyManagement>' in line:
+            in_dep_mgmt = False
+            new_lines.append(line)
+            continue
+
+        if in_dep_mgmt:
+            if '<dependencies>' in line:
+                in_dependencies = True
+                new_lines.append(line)
+                continue
+            if '</dependencies>' in line:
+                in_dependencies = False
+                new_lines.append(line)
+                continue
+
+            if in_dependencies:
+                if '<dependency>' in line:
+                    in_dependency = True
+                    current_dependency_lines = [line]
+                    has_x_version_update = False
+                    continue
+                if '</dependency>' in line:
+                    in_dependency = False
+                    current_dependency_lines.append(line)
+                    if has_x_version_update:
+                        new_lines.extend(current_dependency_lines)
+                    continue
+
+                if in_dependency:
+                    current_dependency_lines.append(line)
+                    if '{x-version-update:' in line:
+                        has_x_version_update = True
+                    continue
+
+                # Prune comments and extra whitespace in depMgmt for a cleaner result
+                if not line.strip():
+                    new_lines.append(line)
+                continue
+
+        # Reporting section removal
+        if '<reporting>' in line:
+            in_reporting = True
+            continue
+        if '</reporting>' in line:
+            in_reporting = False
+            continue
+        if in_reporting:
+            continue
+
+        new_lines.append(line)
+
+    with open(file_path, 'w') as f:
+        # Clean up double empty lines potentially introduced by pruning
+        content = "".join(new_lines)
+        content = re.sub(r'\n\s*\n\s*\n', '\n\n', content)
+        f.write(content)
+
+if __name__ == "__main__":
+    if len(sys.argv) > 2:
+        modernize_pom(sys.argv[1], sys.argv[2])
+    else:
+        print("Usage: python3 modernize_pom.py <file_path> <parent_version>")
+        sys.exit(1)