experimental-code-coverage-config-validator

# Code Coverage Config Validator Use this skill to verify if a Chromium builder is correctly configured in its generated GN arguments (`gn-args.json`) to produce code coverage data. ______________________________________________________________________ ## Inputs When invoking this skill, the caller MUST pass the following inputs in the prompt: - `builders_of_concern`: Target builder names to validate (e.g., `["linux-rel"]`). To locate the Starlark `.star` definition file for each builder, reference: [builder_star_map.json](../experimental-code-coverage-cq-debugger/references/builder_star_map.json). - `language_context`: The programming language context (`"cpp"`, `"objc"`, `"rust"`, `"java"`, `"js"`, or `"ts"`). Consult [language_coverage_map.json][map_ref] for authoritative mappings. ______________________________________________________________________ ## When to Use This Skill - Verifying if a builder has the correct GN arguments for code coverage. - Debugging why code coverage artifacts are missing or not updated. - Triaging a code coverage bug where builder configuration needs validation. ______________________________________________________________________ ## Validation Checks Consult [language_coverage_map.json][map_ref] for the required settings mapped to `language_context`. Verify that the builder's configuration (`gclient_config` and generated `gn-args.json`) satisfies both: - **gclient Configuration**: Inspect `builder_spec.gclient_config` to confirm any `required_gclient_vars` (e.g., `checkout_clang_coverage_tools` set via `apply_configs = ["use_clang_coverage"]`). - **GN Arguments (`gn_args`)**: Inspect generated `gn-args.json` to confirm all `required_gn_args` are present. ______________________________________________________________________ ## Step-by-Step Execution 1. **Locate GN Args File**: Search for `builder_name` inside `infra/config/generated/builders/gn_args_locations.json` to resolve its relative path (e.g., `"try/linux-rel/gn-args.json"`). Read the JSON file at `infra/config/generated/builders/<relative_path>`. 2. **Inspect Configuration**: Examine the `"gn_args"` dictionary in the JSON. 3. **Perform Checks**: Check each required key-value pair as defined in the **Validation Checks** section for the given `language_context`. 4. **Generate Report**: - **Validation Success**: If all checks pass, report builder is valid. - **Validation Failure**: Detail missing or incorrect configurations. Recommend updating the builder's Starlark file and regenerating configs via `lucicfg generate infra/config/main.star`. 5. **Environment Reminder**: If `language_context` is `"cpp"`, `"objc"`, or `"rust"`, append a reminder that local Clang code coverage generation requires `"checkout_clang_coverage_tools": True` in the developer's `~/.gclient` file under `custom_vars`. ______________________________________________________________________ ## Example Outputs ### Example 1: Successful Validation (C++) > **Builder linux-rel validation successful for language context cpp.** All > required GN arguments (`use_clang_coverage = true`, `is_clang = true`, and > `is_debug = false`) are present in `gn-args.json`. ### Example 2: Failed Validation (C++) > **Builder linux-rel for language context cpp requires updates:** > > - **LACKING**: `"is_debug": false` is missing in `gn-args.json`. > > - **SUGGESTED CHANGE**: Update the Starlark builder definition to set > `is_debug = False` and run `lucicfg generate infra/config/main.star`. > > - **REMINDER**: For local C++ coverage generation, ensure your `~/.gclient` > file contains: > > ```python > custom_vars = { > "checkout_clang_coverage_tools": True, > } > ``` ### Example 3: Failed Validation (Java) > **Builder android-x86-rel for language context java requires updates:** > > - **LACKING**: `"use_jacoco_coverage": true` is missing in `gn-args.json`. > - **SUGGESTED CHANGE**: Update the Starlark builder definition to set > `use_jacoco_coverage = True` and regenerate configs via `lucicfg`. [map_ref]: ../../../tools/code_coverage/language_coverage_map.json