Improvement/gdl 14 add reusable prettier diff

README.md

@@ -2,10 +2,10 @@
 
 This project:
 
-* Defines and explains the coding style and workflow for the S3 project. See
+- Defines and explains the coding style and workflow for the S3 project. See
   [CONTRIBUTING.md](CONTRIBUTING.md) for details.
 
-* Provides an `eslint-config-scality` package that can be added as a dependency
+- Provides an `eslint-config-scality` package that can be added as a dependency
   in other projects. That way, coding style can automatically be checked using
   eslint.
 
@@ -22,29 +22,30 @@ To use it in a project:
 
 1. Install Prettier in the project:
 
-   ```sh
-   yarn add --dev prettier
-   # or
-   npm install --save-dev prettier
-   ```
+    ```sh
+    yarn add --dev prettier
+    # or
+    npm install --save-dev prettier
+    ```
 
 2. Copy or extend the configuration:
 
-   ```js
-   // prettier.config.cjs
-   module.exports = require('eslint-config-scality/prettier.config.cjs');
-   ```
+    ```js
+    // prettier.config.cjs
+    module.exports = require('eslint-config-scality/prettier.config.cjs');
+    ```
 
 3. Add convenience scripts:
 
-   ```json
-   {
-     "scripts": {
-       "format": "prettier --write .",
-       "format:check": "prettier --check ."
-     }
-   }
-   ```
+    ```json
+    {
+        "scripts": {
+            "format": "prettier --write .",
+            "format:check": "prettier --check .",
+            "prettier:diff": "scality-prettier-diff"
+        }
+    }
+    ```
 
 Projects may override options locally (for example `tabWidth` or
 `printWidth`) if they have strong legacy constraints, but this configuration
@@ -53,6 +54,19 @@ Node.js codebases. YAML/JSON/Markdown files default to a 2-space indentation
 and Markdown prose is left un-reflowed by default (`proseWrap: 'preserve'`),
 to avoid noisy diffs in existing documentation.
 
+For pull request checks or local review of changed files, this package exposes
+the `scality-prettier-diff` script. It runs Prettier on files returned by
+`git diff --name-only --diff-filter=ACMRT`, defaults to `--check`, and forwards
+remaining arguments to `git diff`.
+
+Examples:
+
+```sh
+yarn run prettier:diff
+yarn run prettier:diff --check HEAD~1..HEAD
+yarn run prettier:diff --write --cached
+```
+
 ## Contributing
 
 - See `CONTRIBUTING.md` for contribution guidelines and coding standards.

bin/prettier-diff.js

@@ -0,0 +1,107 @@
+#!/usr/bin/env node
+
+'use strict';
+
+const { spawnSync } = require('child_process');
+
+const supportedFilePattern = /\.(js|cjs|mjs|ts|tsx|json|ya?ml|md)$/;
+
+function parseArgs(args) {
+    const prettierArgs = [];
+    const diffArgs = [];
+    let hasMode = false;
+
+    args.forEach(arg => {
+        if (arg === '--format') {
+            prettierArgs.push('--write');
+            hasMode = true;
+            return;
+        }
+        if (arg === '--check' || arg === '--write') {
+            prettierArgs.push(arg);
+            hasMode = true;
+            return;
+        }
+        diffArgs.push(arg);
+    });
+
+    if (!hasMode) {
+        prettierArgs.unshift('--check');
+    }
+
+    return { prettierArgs, diffArgs };
+}
+
+function filterSupportedFiles(files) {
+    return files.filter(file => supportedFilePattern.test(file));
+}
+
+function run(command, args, options = {}) {
+    return spawnSync(command, args, {
+        encoding: 'utf8',
+        stdio: ['ignore', 'pipe', 'pipe'],
+        ...options,
+    });
+}
+
+function exitFromResult(result) {
+    if (result.error) {
+        process.stderr.write(`${result.error.message}\n`);
+        process.exit(1);
+    }
+    if (result.signal) {
+        process.stderr.write(`Command terminated by signal ${result.signal}\n`);
+        process.exit(1);
+    }
+    process.exit(result.status);
+}
+
+function getGitRoot() {
+    const result = run('git', ['rev-parse', '--show-toplevel']);
+    if (result.status !== 0) {
+        process.stderr.write(result.stderr);
+        exitFromResult(result);
+    }
+    return result.stdout.trim();
+}
+
+function getChangedFiles(diffArgs, cwd) {
+    const result = run('git', ['diff', '--name-only', '--diff-filter=ACMRT', ...diffArgs], { cwd });
+    if (result.status !== 0) {
+        process.stderr.write(result.stderr);
+        exitFromResult(result);
+    }
+    return result.stdout.split('\n').filter(Boolean);
+}
+
+function main() {
+    const { prettierArgs, diffArgs } = parseArgs(process.argv.slice(2));
+    const rootDir = getGitRoot();
+    const changedFiles = filterSupportedFiles(getChangedFiles(diffArgs, rootDir));
+
+    if (changedFiles.length === 0) {
+        process.stdout.write('No supported files changed; skipping Prettier.\n');
+        return;
+    }
+
+    process.stdout.write(`Running Prettier on ${changedFiles.length} file(s):\n`);
+    changedFiles.forEach(file => process.stdout.write(` - ${file}\n`));
+
+    const result = spawnSync(
+        'yarn',
+        ['run', '--silent', 'prettier', ...changedFiles, ...prettierArgs],
+        { cwd: rootDir, stdio: 'inherit' },
+    );
+    exitFromResult(result);
+}
+
+if (require.main === module) {
+    main();
+}
+
+module.exports = {
+    exitFromResult,
+    filterSupportedFiles,
+    main,
+    parseArgs,
+};

package.json

@@ -1,15 +1,18 @@
 {
     "name": "eslint-config-scality",
-    "version": "8.3.1",
+    "version": "8.3.2",
     "description": "ESLint config for Scality's Node.js coding guidelines",
     "bin": {
-        "mdlint": "./bin/mdlint.js"
+        "mdlint": "./bin/mdlint.js",
+        "scality-prettier-diff": "./bin/prettier-diff.js"
     },
     "main": "index.js",
     "scripts": {
-        "test": "yarn run --silent lint && yarn run --silent lint_md",
+        "test": "yarn run --silent lint && yarn run --silent lint_md && yarn run --silent prettier:diff",
         "lint": "eslint -c eslint.config.cjs $(git ls-files '*.js')",
-        "lint_md": "node bin/mdlint.js $(git ls-files '*.md')"
+        "lint_md": "node bin/mdlint.js $(git ls-files '*.md')",
+        "prettier": "prettier",
+        "prettier:diff": "node tests/prettier-diff.js"
     },
     "repository": {
         "type": "git",
@@ -20,7 +23,8 @@
         "markdownlint": "0.31.1"
     },
     "devDependencies": {
-        "eslint": "^9.9.1"
+        "eslint": "^9.9.1",
+        "prettier": "^3.4.2"
     },
     "keywords": [
         "eslint",

tests/prettier-diff.js

@@ -0,0 +1,60 @@
+'use strict';
+
+const assert = require('assert');
+const { exitFromResult, filterSupportedFiles, parseArgs } = require('../bin/prettier-diff');
+
+assert.deepStrictEqual(parseArgs([]), {
+    prettierArgs: ['--check'],
+    diffArgs: [],
+});
+
+assert.deepStrictEqual(parseArgs(['--format', 'HEAD~1..HEAD']), {
+    prettierArgs: ['--write'],
+    diffArgs: ['HEAD~1..HEAD'],
+});
+
+assert.deepStrictEqual(parseArgs(['--write', '--cached']), {
+    prettierArgs: ['--write'],
+    diffArgs: ['--cached'],
+});
+
+assert.deepStrictEqual(
+    filterSupportedFiles([
+        'index.js',
+        'lib/config.cjs',
+        'src/main.ts',
+        'workflow.yaml',
+        'README.md',
+        'package-lock.json',
+        'image.png',
+        'script.sh',
+    ]),
+    ['index.js', 'lib/config.cjs', 'src/main.ts', 'workflow.yaml', 'README.md', 'package-lock.json'],
+);
+
+const originalExit = process.exit;
+const originalStderrWrite = process.stderr.write;
+
+let exitCode;
+let stderr = '';
+
+process.exit = code => {
+    exitCode = code;
+    throw new Error('process.exit');
+};
+process.stderr.write = message => {
+    stderr += message;
+};
+
+assert.throws(
+    () =>
+        exitFromResult({
+            error: new Error('spawn yarn ENOENT'),
+        }),
+    /process\.exit/,
+);
+assert.strictEqual(exitCode, 1);
+assert.match(stderr, /spawn yarn ENOENT/);
+
+process.exit = originalExit;
+process.stderr.write = originalStderrWrite;

yarn.lock

@@ -543,6 +543,11 @@ prelude-ls@^1.2.1:
   resolved "https://registry.yarnpkg.com/prelude-ls/-/prelude-ls-1.2.1.tgz#debc6489d7a6e6b0e7611888cec880337d316396"
   integrity sha512-vkcDPrRZo1QZLbn5RLGPpg/WmIQ65qoWWhcGKf/b5eplkkarX0m9z8ppCat4mlOqUsWpyNuYgO3VRyrYHSzX5g==
 
+prettier@^3.4.2:
+  version "3.8.3"
+  resolved "https://registry.yarnpkg.com/prettier/-/prettier-3.8.3.tgz#560f2de55bf01b4c0503bc629d5df99b9a1d09b0"
+  integrity sha512-7igPTM53cGHMW8xWuVTydi2KO233VFiTNyF5hLJqpilHfmn8C8gPf+PS7dUT64YcXFbiMGZxS9pCSxL/Dxm/Jw==
+
 punycode@^2.1.0:
   version "2.1.1"
   resolved "https://registry.yarnpkg.com/punycode/-/punycode-2.1.1.tgz#b58b010ac40c22c5657616c8d2c2c02c7bf479ec"