update-expected-app-size

# Update Expected App Size Files Download updated expected app size files from Azure DevOps artifacts for the current branch's PR build, and apply them to the repository. ## When to Use - App size tests failed in CI and the user wants to update the expected files - User asks to "update app size", "download expected files", or "fix app size test failures" - User wants to pull the updated expected files from a recent CI build ## Background The app size tests (`tests/dotnet/UnitTests/AppSizeTest.cs`) compare the built app's size and preserved APIs against expected files stored in `tests/dotnet/UnitTests/expected/`. When the test detects a difference and `WRITE_KNOWN_FAILURES` is not set, it writes the updated expected file to `$(Build.ArtifactStagingDirectory)/updated-expected-sizes/`, and a pipeline step publishes this directory as a build artifact. The artifact name follows the pattern `{uploadPrefix}updated-expected-sizes-{testPrefix}-{attempt}` (e.g., `updated-expected-sizes-dotnettests_ios-1`). Because the expected files can be very big, the test uploads a unified **diff** for each changed expected file rather than the whole file. Inside the artifact, files are named after the test variant with a `.diff` suffix: - `{Platform}-{Variant}-size.txt.diff` — e.g., `iOS-CoreCLR-Interpreter-size.txt.diff`, `iOS-CoreCLR-R2R-size.txt.diff`, `iOS-NativeAOT-TrimmableStatic-size.txt.diff`, `MacOSX-CoreCLR-Interpreter-size.txt.diff` - `{Platform}-{Variant}-preservedapis.txt.diff` — e.g., `iOS-CoreCLR-Interpreter-preservedapis.txt.diff`, `MacCatalyst-CoreCLR-R2R-preservedapis.txt.diff` Each diff is a unified diff (relative to the repository root) that can be applied with `git apply -p1` or `patch -p1`. The expected files on disk are at: - `tests/dotnet/UnitTests/expected/{Platform}-{Variant}-size.txt` - `tests/dotnet/UnitTests/expected/{Platform}-{Variant}-preservedapis.txt` ## Workflow ### 1. Determine the current branch and PR ```bash BRANCH=$(git branch --show-current) # Find the PR number for this branch gh pr list --head "$BRANCH" --repo dotnet/macios --json number,url --jq '.[0]' ``` If no PR is found, inform the user that this skill requires a PR to exist for the current branch (so that CI has run). ### 2. Find the Azure DevOps build The CI builds for PRs in dotnet/macios run in the `devdiv` Azure DevOps organization, project `DevDiv`. Use the GitHub PR checks to find the Azure DevOps build URL: ```bash gh pr checks <PR_NUMBER> --repo dotnet/macios ``` Look for a check that links to Azure DevOps. The build URL will look like: ``` https://devdiv.visualstudio.com/DevDiv/_build/results?buildId=XXXXXXX ``` Extract the `buildId` from the URL. ### 3. Download the artifacts Use the Azure DevOps REST API to list and download artifacts: ```bash # List artifacts for the build TOKEN=$(az account get-access-token --resource 499b84ac-1321-427f-aa17-267ca6975798 --query accessToken -o tsv) curl -s "https://devdiv.visualstudio.com/DevDiv/_apis/build/builds/{buildId}/artifacts?api-version=7.0" \ -H "Authorization: Bearer $TOKEN" ``` Look for artifacts whose names contain `updated-expected-sizes` (e.g., `updated-expected-sizes-dotnettests_ios-1`). Get the artifact's `downloadUrl` and download it: ```bash # Get the download URL for a specific artifact ARTIFACT_INFO=$(curl -s "https://devdiv.visualstudio.com/DevDiv/_apis/build/builds/{buildId}/artifacts?artifactName={artifactName}&api-version=7.0" \ -H "Authorization: Bearer $TOKEN") DOWNLOAD_URL=$(echo "$ARTIFACT_INFO" | python3 -c "import sys,json; print(json.load(sys.stdin)['resource']['downloadUrl'])") # Download the artifact zip curl -sL "$DOWNLOAD_URL" -H "Authorization: Bearer $TOKEN" -o artifact.zip ``` If `az` is not available or not authenticated, direct the user to download manually from the Azure DevOps build artifacts page. ### 4. Place the files Extract the downloaded artifact zip and apply each diff to the expected directory from the repository root: ```bash unzip -o artifact.zip -d /tmp/updated-sizes/ # Each '*.txt.diff' is a unified diff relative to the repository root. for diff in /tmp/updated-sizes/*/*.txt.diff; do git apply -p1 "$diff" done ``` The diffs reference `tests/dotnet/UnitTests/expected/<name>.txt` directly, so applying them updates (or creates) the expected files in place. If a diff fails to apply cleanly (e.g., the expected file changed since the CI build), re-run the failing app size test locally with `WRITE_KNOWN_FAILURES=1` to regenerate the file (see the "Run Locally" fallback). ### 5. Verify and commit After placing the files: 1. Run `git diff` to show what changed 2. Ask the user if the changes look correct 3. If confirmed, commit the changes: ```bash git add tests/dotnet/UnitTests/expected/ git commit -m "[tests] Update expected app size files" ``` ## Fallback: Manual Download If automated download fails (auth issues, etc.), provide the user with: 1. The Azure DevOps build URL 2. Instructions to navigate to the build → Summary → Artifacts section 3. Look for individual artifacts whose names contain `updated-expected-sizes` 4. Download the artifact zip, extract it, and apply the `.txt.diff` files (e.g., `iOS-CoreCLR-Interpreter-size.txt.diff`) from the repository root with `git apply -p1 <file>` ## Fallback: Run Locally If the user can build locally, they can update the expected files directly: ```bash WRITE_KNOWN_FAILURES=1 tests-dotnet AppSizeTest ``` This runs the tests, updates the expected files in place, and marks the tests as passed.