Experimental Code Coverage Installer

Code Coverage Installer Skill

This skill guides the verification and initialization of the development environment.

When to Use This Skill

Use this skill when:

• Preparing the workspace for running code coverage pipelines, local generation, or triage.
• Verifying the presence and integrity of code coverage tools and code repositories.

How to Use This Skill

The primary and recommended method to verify and initialize all code coverage dependencies automatically is to run the installer script with the required --infra-dir argument:

python3 tools/code_coverage/code_coverage_installer.py --infra-dir <path_to_infra_dir>

[!IMPORTANT] If the user has not explicitly provided an infra directory path in their request, you must ask them to specify one before running the installer or starting manual verification. Do not choose a default directory or initialize the repository without the user's explicit consent.

If you prefer to perform checks manually, or if you need to troubleshoot specific components, follow the manual checklist workflow below:

Step 1: Verify Chromium Checkout on Disk

Before performing any code coverage operations, verify that a valid Chromium source code checkout is available on the local disk.

1. Locate the Workspace Root: Confirm you are inside or pointing to the root of a Chromium checkout (typically containing the src/ directory).
2. Verify Vital Files: Check for the presence of the following critical files and directories to ensure the checkout is valid:
   • src/DEPS: Contains Chromium's external dependency definitions.
   • src/tools/code_coverage/: The root directory for coverage-related scripts.
3. Verdict: If these files/directories are not present, stop and notify the user. A valid local Chromium checkout is strictly required.

Step 2: Verify LLVM Coverage Tools

Verify that LLVM coverage tools are available in third_party/.

1. Check for Existing Tooling: Check if the following executables exist:
   • src/third_party/llvm-build/Release+Asserts/bin/llvm-cov
   • src/third_party/llvm-build/Release+Asserts/bin/llvm-profdata
2. If Tools are Present: Proceed to the next step.
3. If Tools are Missing: Prompt the user for confirmation before modifying .gclient (as it will affect future sync speeds).
   • If they confirm, configure .gclient so that coverage tools are fetched during workspace syncs:
     1. Open the .gclient configuration file (located in the directory above src/).
     2. Add the following entry to the custom_vars dictionary:

        "checkout_clang_coverage_tools": True,

     3. Run hooks to download the package:

        gclient runhooks

   • If they do not confirm, stop and notify the user that LLVM tools are required for coverage verification.
4. Verdict: If the tools are still missing, stop and notify the user.

Step 3: Verify and Setup Code Coverage Recipe Code

Verify that the code coverage recipe codebase is available under the specified <infra_dir>. This code runs on LUCI builders to generate raw coverage data and upload it to GCS.

1. Check for Existing Recipes Checkout: Check if the following directory exists under your <infra_dir>:
   • <infra_dir>/build/recipes/recipe_modules/code_coverage/
2. Verify Key Recipe Files: Confirm that the following files exist inside code_coverage/:
   • api.py: Contains the recipe module API.
   • constants.py: Contains configuration constants.
   • properties.proto: Defines configuration properties.
3. If Recipe Code is Present: Proceed to the next step.
4. If Recipe Code is Missing: Follow the setup instructions in Step 5.
5. Verdict: If the recipe repository is missing after setup, stop and notify the user.