chore(ci): enable workflows and scripts on preview (#15581)

[noahdietz]

Cherry pick commit from main for #15581.

[gemini-code-assist]

Summary of Changes

Hello @noahdietz, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request enhances the continuous integration (CI) pipeline by introducing greater flexibility in how conditional tests are executed. By parameterizing the target branch for Git operations, the CI workflows can now be effectively run against branches other than main, such as a preview branch, without requiring manual modifications. This change streamlines the testing process for different development stages.

Highlights

• CI Script Flexibility: Modified ci/run_conditional_tests.sh to use a configurable TARGET_BRANCH variable, defaulting to main, instead of hardcoding main for Git operations.
• Conditional Test Execution: Updated conditional logic for presubmit and continuous builds to reference the TARGET_BRANCH for fetching history and determining diffs.

Changelog

• ci/run_conditional_tests.sh
  • Introduced TARGET_BRANCH variable to dynamically specify the branch for Git diff and fetch operations.
  • Updated presubmit and continuous build logic to utilize the new TARGET_BRANCH variable.
  • Switched if condition syntax from [ ... ] to [[ ... ]] for improved shell scripting practices.

Ignored Files

• Ignored by pattern: .github/workflows/** (3)
  • .github/workflows/docs.yml
  • .github/workflows/lint.yml
  • .github/workflows/unittest.yml

Activity

• This pull request is a cherry-pick of a commit from main (specifically, chore(ci): enable workflows and scripts on preview #15581).

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[gemini-code-assist]

Code Review

This pull request updates the run_conditional_tests.sh script to be more flexible by allowing a configurable target branch instead of a hardcoded main branch. The changes also improve the script's robustness by using [[...]] for tests. The code is well-written. I've added one suggestion to refactor a conditional block to reduce code duplication and improve maintainability.

[gemini-code-assist]

To improve maintainability and reduce code duplication, this conditional logic can be refactored. By setting a FETCH_DEPTH variable within the if/elif blocks, you can use a single git fetch command afterwards. This makes the script's intent clearer and easier to modify in the future.

Suggested change

	if [[ ${BUILD_TYPE} == "presubmit" ]]; then
	# For presubmit build, we want to know the difference from the
	# common commit in origin/main.
	GIT_DIFF_ARG="origin/main..."
	# common commit in the target branch.
	GIT_DIFF_ARG="origin/$TARGET_BRANCH..."
	# Then fetch enough history for finding the common commit.
	git fetch origin main --deepen=200
	git fetch origin "$TARGET_BRANCH" --deepen=200
	elif [ ${BUILD_TYPE} == "continuous" ]; then
	elif [[ ${BUILD_TYPE} == "continuous" ]]; then
	# For continuous build, we want to know the difference in the last
	# commit. This assumes we use squash commit when merging PRs.
	GIT_DIFF_ARG="HEAD~.."
	# Then fetch one last commit for getting the diff.
	git fetch origin main --deepen=1
	git fetch origin "$TARGET_BRANCH" --deepen=1
	FETCH_DEPTH=""
	if [[ ${BUILD_TYPE} == "presubmit" ]]; then
	# For presubmit build, we want to know the difference from the
	# common commit in the target branch.
	GIT_DIFF_ARG="origin/$TARGET_BRANCH..."
	FETCH_DEPTH=200
	elif [[ ${BUILD_TYPE} == "continuous" ]]; then
	# For continuous build, we want to know the difference in the last
	# commit. This assumes we use squash commit when merging PRs.
	GIT_DIFF_ARG="HEAD~.."
	FETCH_DEPTH=1
	fi
	if [[ -n "${FETCH_DEPTH}" ]]; then
	# Fetch enough history for getting the diff.
	git fetch origin "$TARGET_BRANCH" --deepen="${FETCH_DEPTH}"
	fi