codeguard-objc

Objective-C Codeguard Gate

Goal: turn "looks fine" into repeatable tool evidence, and honestly distinguish pass, fail, unable to verify, and planned.

30-second start

1. At the repository root, confirm 无专用标记文件 or the target file exists.
2. Probe tools:clang-tidy --version。
3. First do a read-only check:bash -c 'find . -name '"'"'*.m'"'"' -o -name '"'"'*.mm'"'"' | xargs -r clang-tidy --quiet'。
4. Classify results into: code violations, missing configuration, missing tools, tool internal errors.
5. Only perform on safely fixable items:clang-format -i '{file}'。
6. Re-run lint, and execute the project's existing test/build gates.

Can directly propose:

• "Check this Objective-C project, do not modify first, give me the lint failure classification."
• "Only fix Objective-C formatting issues, list semantic issues first."
• "Verify Objective-C lint, test, and build evidence before committing."

Capability boundaries

✅ Good at handling

1. Identify the Objective-C workspace based on .m, .mm and project markers.
2. Run clang-tidy --quiet '{file}' and retain exit code, scope, and tool version.
3. Distinguish formatting, static rules, configuration, dependency, and environment failures.
4. Use clang-format -i '{file}' to handle reversible issues and re-scan.
5. Report local results and CI/build/test evidence in layers.

⚠️ Requires conditions

1. The target tool must be installed and its version compatible with project constraints.
2. Must be executed from the correct repository or module root directory.
3. If the project has custom configuration, the committed configuration prevails.
4. Whether generated code, vendor, and cache directories are scanned must follow repository rules.

❌ Not applicable

1. Do not treat formatter pass as compilation, test, or security audit pass.
2. Do not silently install tools, upgrade dependencies, or modify team rules.
3. Do not use suppress/ignore/raising thresholds to mask real issues.
4. Do not claim "check passed" when tools or configuration are missing.

When to use

• The user requests checking or fixing Objective-C code style.
• AI modified .m, .mm, requiring pre-commit verification.
• CI shows failures related to clang-tidy --quiet '{file}' .
• Need to determine whether an issue can be auto-fixed or must be handled manually.

When not to use

• The main task is learning language syntax, framework design, or business modeling; use the corresponding language professional skill instead.
• The main task is dependency vulnerabilities, security auditing, or license governance; use a dedicated security skill.
• When the user only asks to explain an error and there is no project context, first do a local explanation and do not claim the repository is all green.

Data and security

This skill does not collect, upload, send, or store user code and credentials. By default, it only reads local repository configuration and runs local tools; it does not install dependencies over the network, and does not record tokens, passwords, or private source code. Before any automatic fix, check the diff first; destructive or large-scale changes must be explicitly confirmed by the user.

Execution Contract

Item	Current Fact
Status	stable(since Codeguard V0.4)
File Extensions	.m, .mm
Project Marker	No dedicated marker file
Integration Configuration	The repository's existing configuration prevails
Tool Preparation	clang-tidy + clang-format
Probe Command	使用命令查找与项目配置检查
lint	clang-tidy --quiet '{file}'
format/fix	clang-format -i '{file}'
Project-level gate	bash -c 'find . -name '"'"'*.m'"'"' -o -name '"'"'*.mm'"'"' | xargs -r clang-tidy --quiet'

Standard Workflow

Step 1: Determine the Real Scope

Confirm the repository root, module roots, generated directories, vendor directories, and user-specified files. For multi-module projects, first list the modules that will be scanned; do not guess based on the current directory.

Step 2: Read the Project Contract

Read the actual commands in the repository's existing configuration and CI. Repository configuration takes precedence over this skill's examples; if the two conflict, report the difference first.

Step 3: Probe Tools and Versions

Run 对应工具 --version. Missing tools, incompatible versions, or configurations that cannot be loaded are all recorded as "unable to verify", not as passing.

Step 4: Run Read-Only Checks

Run bash -c 'find . -name '"'"'*.m'"'"' -o -name '"'"'*.mm'"'"' | xargs -r clang-tidy --quiet', recording the command, working directory, exit code, tool version, and the first actionable error.

Step 5: Failure Classification

Type	Typical Signal	Handling
Format	Indentation, whitespace, import order	Formatter allowed, then check the diff
Static Rules	unused, complexity, naming, dangerous APIs	Minimal semantic fixes, no bulk guessing
Configuration	parser/config/schema not found	Fix the integration or report the prerequisites
Environment	command not found, version conflict	Report installation/version requirements; do not install silently
Tool Internal Error	crash, timeout, parser exception	Preserve the original evidence and narrow the reproduction scope

Step 6: Controlled Fixes

Prefer to run clang-format -i '{file}'. Only handle issues that are certain and reversible; dependency upgrades, rule exemptions, generated files, and business semantic changes must be explained separately.

Step 7: Verification Loop

Re-run the same lint command, then run the project's existing tests and build. Only write "passing" when the command, scope, and exit code are all clear; otherwise write "not run" or "unable to verify".

Rules

1. Re-verify with the same command: after a fix, the original command that triggered the failure must be re-run.
2. Layered Evidence: lint, format, compile, test, and security are reported separately.
3. Minimal Changes: do not refactor along the way, and do not expand style fixes into business rewrites.
4. Configuration First: do not overwrite the project's existing ignore, dialect, target, or version constraints.
5. No Fabrication: Tools that were not run, configurations that were not seen, and platforms that were not verified must be explicitly marked.

Output template

Objective-C Codeguard 结果
- 范围：<仓库/模块/文件>
- 工具：<名称与版本>
- 命令：<实际命令>
- 状态：PASS / FAIL / UNVERIFIED / PLANNED
- 发现：<按格式/规则/配置/环境分类>
- 修改：<文件与原因；无修改写 none>
- 复验：<命令、退出码>
- 未验证：<测试/构建/平台差异>

Gotchas

1. A missing tool is not a pass — must output UNVERIFIED and a clear preparation method.
2. A formatter is not a linter — all-green formatting cannot override static rules or compilation errors.
3. The root directory determines the result — running in the wrong module may miss checks or load the wrong configuration.
4. Placeholders are not literal parameters — {file} must be replaced with real, authorized paths.
5. Auto-fixes may expand the diff — after fixing, review the diff first, then run the regression gate.
6. Generated and vendor directories require an explicit policy — third-party content must not be scanned or modified arbitrarily across the whole repository.

Domain pitfalls and fixes

1. Domain pitfall — Objective-C++ .mm files must use a matching SDK and compilation parameters; standalone clang-tidy results may be distorted.

When information is insufficient

Do not just say "please provide more information." First give a safe read-only inspection plan, and list the specific items that still need confirmation:

1. Repository/module root directory;
2. Target tool and version;
3. Project configuration file;
4. The authoritative command in CI;
5. Whether auto-fixing is allowed.

FAQ

Q1: If the tool is not installed, can we conclude the code is fine? No. The status must be UNVERIFIED。

Q2: Can ignore or suppression be added automatically? No. Exemptions may be granted only when the user explicitly accepts them and the reason is recorded.

Q3: Why does it still fail after formatting? The formatter only covers formatting; static rules, configuration, compilation, and tests still need to be handled separately.

Q4: Should generated code be scanned? By default, follow the repository configuration; if there are no rules, exclude generated/vendor first, then explain to the user.

Q5: How can too many changes at once be avoided? Fix in batches by failure category and file first, and rerun the original command and review the diff for each batch.

Q6: If it passes locally, can we say CI will pass? No. The CI versions, environment variables, operating system, and command scope still need to be aligned.

Load resources on demand

• When encountering exit codes, failure classification, or exemption decisions, read references/rules/gate-rules.md。
• When the language registry, toolchain, and project configuration need to be checked, read references/tooling/toolchain.md。
• When copyable task examples are needed, read by scenario examples/, and it is not necessary to load all of them at once.