feat(fmt): support custom cache directories

packages/rstack/src/fmt/cli.ts

@@ -13,6 +13,7 @@ import type { FmtMode, FmtRunResult, ResolvedFmtConfig } from './types.ts';
 
 interface ParsedFmtCLIArgs {
   cache: boolean;
+  cacheLocation?: string;
   mode: FmtMode;
   patterns: string[];
   ignorePaths: string[];
@@ -39,6 +40,7 @@ ${color.cyan('Options')}:
   --ignore-path <path>             Path to an additional ignore file (repeatable)
   -u, --ignore-unknown             Ignore unknown files
   --no-cache                       Disable the formatting cache
+  --cache-location <path>          Path to the formatting cache directory
   --no-error-on-unmatched-pattern  Do not error when no files match
   --with-node-modules              Process files inside node_modules
   --parallel-workers <count>       Number of parallel workers
@@ -68,6 +70,7 @@ const parseFmtCLIArgs = (args: string[]): ParsedFmtCLIArgs => {
       'ignore-path': { type: 'string', multiple: true },
       'ignore-unknown': { type: 'boolean', short: 'u' },
       'no-cache': { type: 'boolean' },
+      'cache-location': { type: 'string' },
       'no-error-on-unmatched-pattern': { type: 'boolean' },
       'with-node-modules': { type: 'boolean' },
       'parallel-workers': { type: 'string' },
@@ -88,6 +91,11 @@ const parseFmtCLIArgs = (args: string[]): ParsedFmtCLIArgs => {
 
   const mode = check ? 'check' : listDifferent ? 'list-different' : 'write';
   const cache = !(values.noCache ?? false);
+  const cacheLocation = cache ? values.cacheLocation : undefined;
+  if (cacheLocation === '') {
+    throw new Error('The --cache-location option requires a path.');
+  }
+
   const ignorePaths = values.ignorePath ?? [];
   const ignoreUnknown = values.ignoreUnknown ?? false;
   const noErrorOnUnmatchedPattern = values.noErrorOnUnmatchedPattern ?? false;
@@ -111,6 +119,7 @@ const parseFmtCLIArgs = (args: string[]): ParsedFmtCLIArgs => {
 
   return {
     cache,
+    cacheLocation,
     mode,
     patterns: positionals,
     ignorePaths,
@@ -247,6 +256,7 @@ const runFmtCLI = async (args: string[]): Promise<void> => {
   try {
     const {
       cache,
+      cacheLocation,
       help,
       ignorePaths,
       ignoreUnknown,
@@ -277,11 +287,13 @@ const runFmtCLI = async (args: string[]): Promise<void> => {
       return;
     }
 
+    const cacheDirPath = cacheLocation ? path.resolve(cwd, cacheLocation) : undefined;
     const config = await loadFmtConfig(cwd);
     const files = await discoverFmtFiles({
       cwd,
       patterns,
       config,
+      excludedDirPath: cacheDirPath,
       ignorePaths,
       withNodeModules,
     });
@@ -297,7 +309,12 @@ const runFmtCLI = async (args: string[]): Promise<void> => {
     }
 
     let cacheContext;
-    if (cache) {
+    if (cacheDirPath) {
+      cacheContext = {
+        filePath: path.join(cacheDirPath, fmtCacheFileName),
+        rootPath: config.rootPath,
+      };
+    } else if (cache) {
       const cacheDir = await ensureProjectCacheDir(config.rootPath);
       if (cacheDir.status === 'available') {
         cacheContext = {

packages/rstack/src/fmt/discovery.ts

@@ -1,3 +1,4 @@
+import path from 'node:path';
 import { createFmtOptionsResolver, type FmtOptionsResolver } from './config.ts';
 import { discoverFmtPaths } from './discoverPaths.ts';
 import { createIgnoreMatcher } from './ignore.ts';
@@ -11,26 +12,37 @@ const createFileRequest = (
   options: resolveOptions(filePath),
 });
 
+const createDirMatcher = (dirPath: string): ((filePath: string) => boolean) => {
+  const prefix = dirPath.endsWith(path.sep) ? dirPath : `${dirPath}${path.sep}`;
+  return (filePath) => filePath === dirPath || filePath.startsWith(prefix);
+};
+
 /** Discovers worker-ready files without automatically reading Prettier config or ignore files. */
 const discoverFmtFiles = async ({
   cwd,
+  excludedDirPath,
   patterns,
   ignorePaths,
   withNodeModules,
   config,
 }: DiscoverFmtFilesOptions): Promise<FmtFileRequest[]> => {
   const isIgnored = await createIgnoreMatcher({ config, cwd, ignorePaths });
+  const isExcluded = excludedDirPath ? createDirMatcher(excludedDirPath) : undefined;
+  const shouldIgnore = isExcluded
+    ? (filePath: string, isDirectory = false) =>
+        isExcluded(filePath) || isIgnored(filePath, isDirectory)
+    : isIgnored;
   const candidates = await discoverFmtPaths({
     cwd,
     patterns,
     withNodeModules,
-    isIgnored,
+    isIgnored: shouldIgnore,
   });
   if (candidates.length === 0) {
     return [];
   }
 
-  const filePaths = candidates.filter((filePath) => !isIgnored(filePath));
+  const filePaths = candidates.filter((filePath) => !shouldIgnore(filePath));
   const resolveOptions = createFmtOptionsResolver(config);
   const files = filePaths.map((filePath) => createFileRequest(filePath, resolveOptions));
   if (!files.some((file) => file.options.plugins?.length)) {

packages/rstack/src/fmt/types.ts

@@ -55,6 +55,8 @@ interface ResolvedFmtConfig {
 interface DiscoverFmtFilesOptions {
   /** Absolute directory used to resolve input paths. */
   cwd: string;
+  /** Absolute directory to exclude from formatting. */
+  excludedDirPath?: string;
   /** Files, directories, and positive or negative globs. Defaults to the current directory. */
   patterns?: string[];
   /** Ignore files resolved from `cwd`; each file's patterns are relative to its own directory. */

packages/rstack/tests/cli/fmt/index.test.ts

@@ -187,10 +187,18 @@ test.each([
 
 test('--no-cache bypasses cache reads and writes', () => {
   writeProjectFile('index.ts', 'const value=1');
-
-  const first = runFmt(['--no-cache', 'index.ts']);
+  writeProjectFile('custom-cache/v1.json', '{"value":true}');
+
+  const first = runFmt([
+    '--no-cache',
+    '--cache-location',
+    'custom-cache',
+    'index.ts',
+    'custom-cache/v1.json',
+  ]);
 
   expect(first.status).toBe(0);
+  expect(readProjectFile('custom-cache/v1.json')).toBe('{ "value": true }\n');
   expect(existsSync(path.join(projectPath, '.rstack'))).toBe(false);
 
   writeProjectFile('.rstack/cache/fmt-v1.json', 'stale');
@@ -203,6 +211,38 @@ test('--no-cache bypasses cache reads and writes', () => {
   expect(existsSync(path.join(projectPath, '.rstack/cache/.gitignore'))).toBe(false);
 });
 
+test.each(['relative', 'absolute'] as const)('uses a %s custom cache location', (kind) => {
+  const cacheDir = path.join(projectPath, 'custom-cache');
+  const cacheLocation = kind === 'relative' ? path.relative(projectPath, cacheDir) : cacheDir;
+  const cachePath = path.join(cacheDir, 'v1.json');
+  writeProjectFile('index.ts', 'const value = 1;\n');
+
+  const result = runFmt(['--cache-location', cacheLocation, 'index.ts']);
+
+  expect(result.status).toBe(0);
+  expect(JSON.parse(readFileSync(cachePath, 'utf8'))).toMatchObject({
+    version: 1,
+    files: {
+      'index.ts': [expect.any(String), expect.any(String), 'clean'],
+    },
+  });
+  expect(existsSync(path.join(projectPath, 'custom-cache/.gitignore'))).toBe(false);
+  expect(existsSync(path.join(projectPath, '.rstack'))).toBe(false);
+});
+
+test('excludes the custom cache directory from formatting', () => {
+  const cacheLocation = 'custom-cache';
+  writeProjectFile('index.ts', 'const value = 1;\n');
+  writeProjectFile('custom-cache/nested/ignored.ts', 'const value=2');
+  expect(runFmt(['--cache-location', cacheLocation, 'index.ts']).status).toBe(0);
+
+  const result = runFmt(['--cache-location', cacheLocation, '.']);
+
+  expect(result.status).toBe(0);
+  expectWriteSummary(result.stdout, 2, 0);
+  expect(readProjectFile('custom-cache/nested/ignored.ts')).toBe('const value=2');
+});
+
 test('uses an explicit config root cache from a subdirectory', () => {
   const appPath = path.join(projectPath, 'packages/app');
   writeProjectFile('packages/app/index.ts', 'const value=1');

packages/rstack/tests/fmt/__snapshots__/cli.test.ts.snap

@@ -13,6 +13,7 @@ Options:
   --ignore-path <path>             Path to an additional ignore file (repeatable)
   -u, --ignore-unknown             Ignore unknown files
   --no-cache                       Disable the formatting cache
+  --cache-location <path>          Path to the formatting cache directory
   --no-error-on-unmatched-pattern  Do not error when no files match
   --with-node-modules              Process files inside node_modules
   --parallel-workers <count>       Number of parallel workers

packages/rstack/tests/fmt/cli.test.ts

@@ -127,6 +127,23 @@ test('parses --no-cache', () => {
   expect(parseFmtCLIArgs(['--no-cache']).cache).toBe(false);
 });
 
+test('parses --cache-location', () => {
+  expect(parseFmtCLIArgs(['--cache-location', '.cache/fmt']).cacheLocation).toBe('.cache/fmt');
+});
+
+test('--no-cache ignores --cache-location', () => {
+  expect(parseFmtCLIArgs(['--no-cache', '--cache-location='])).toMatchObject({
+    cache: false,
+    cacheLocation: undefined,
+  });
+});
+
+test('rejects an empty cache location', () => {
+  expect(() => parseFmtCLIArgs(['--cache-location='])).toThrow(
+    'The --cache-location option requires a path.',
+  );
+});
+
 test('parses --with-node-modules', () => {
   expect(parseFmtCLIArgs(['--with-node-modules']).withNodeModules).toBe(true);
 });

packages/rstack/tests/fmt/discovery.test.ts

@@ -60,6 +60,30 @@ test('excludes .rstack from discovery', async () => {
   });
 });
 
+test('excludes a custom cache directory', async () => {
+  await withTempProject(async (rootPath) => {
+    const cacheDir = path.join(rootPath, 'custom-cache');
+    const cacheFile = writeProjectFile(rootPath, 'custom-cache/v1.json', '{}');
+    writeProjectFile(rootPath, 'custom-cache/nested/ignored.ts');
+    writeProjectFile(rootPath, 'index.ts');
+
+    const discoveredFiles = await discoverFmtFiles({
+      cwd: rootPath,
+      excludedDirPath: cacheDir,
+      config: normalizeFmtConfig(undefined, rootPath),
+    });
+    const explicitFile = await discoverFmtFiles({
+      cwd: rootPath,
+      excludedDirPath: cacheDir,
+      patterns: [cacheFile],
+      config: normalizeFmtConfig(undefined, rootPath),
+    });
+
+    expect(relativePaths(rootPath, discoveredFiles)).toEqual(['index.ts']);
+    expect(explicitFile).toEqual([]);
+  });
+});
+
 test('keeps files re-included by a CLI ignore file during directory traversal', async () => {
   await withTempProject(async (rootPath) => {
     writeProjectFile(rootPath, '.prettierignore', 'generated/*\n!generated/keep.ts\n');

website/docs/en/guide/cli/fmt.mdx

@@ -133,6 +133,18 @@ Without this option, `rs fmt` stores cache data in `.rstack/cache/fmt` under the
 
 See [Cache](../formatting#cache) for cache behavior and cleanup guidance.
 
+### `--cache-location <path>`
+
+Store the persistent cache in a custom directory:
+
+```bash
+rs fmt --cache-location .cache/rs-fmt
+```
+
+Relative paths are resolved from the current working directory, while absolute paths are used as-is. The directory is created as needed and excluded from file discovery. Unlike the default cache location, a custom directory does not receive an automatic `.gitignore`; exclude it from version control or manage it through your CI cache configuration.
+
+When both options are provided, `--no-cache` takes precedence and the custom directory is not excluded from file discovery.
+
 ### `--no-error-on-unmatched-pattern`
 
 Exit successfully without diagnostics when no files match the provided paths or globs, including when all matching files are ignored:

website/docs/en/guide/formatting.mdx

@@ -180,6 +180,8 @@ define.fmt({
 
 The default cache directory is `.rstack/cache/fmt` under the Rstack configuration root. When a command runs from a subdirectory, it continues to use the cache next to the resolved `rstack.config.*` file. Stdin formatting does not use this cache.
 
+Use [`--cache-location <path>`](./cli/fmt#--cache-location-path) to store the cache in a different directory. Relative paths are resolved from the current working directory. Custom directories are excluded from file discovery but are not automatically ignored by Git.
+
 Use [`--no-cache`](./cli/fmt#--no-cache) to run without reading, creating, or updating the cache:
 
 ```bash

website/docs/zh/guide/cli/fmt.mdx

@@ -133,6 +133,18 @@ rs fmt --no-cache
 
 缓存行为和清理方式请参考[缓存](../formatting#cache)。
 
+### `--cache-location <path>`
+
+将持久化缓存保存到自定义目录：
+
+```bash
+rs fmt --cache-location .cache/rs-fmt
+```
+
+相对路径基于当前工作目录解析，绝对路径则原样使用。目录会在需要时自动创建，并从文件发现中排除。与默认缓存位置不同，自定义目录不会自动生成 `.gitignore`；请将其排除在版本控制之外，或通过 CI 缓存配置进行管理。
+
+同时使用两个选项时，优先使用 `--no-cache`，且不会从文件发现中排除自定义目录。
+
 ### `--no-error-on-unmatched-pattern`
 
 如果传入的路径或 glob 没有匹配任何文件（包括所有匹配文件均被忽略的情况），则不输出诊断信息并成功退出：

website/docs/zh/guide/formatting.mdx

@@ -180,6 +180,8 @@ define.fmt({
 
 默认缓存目录位于 Rstack 配置根目录下的 `.rstack/cache/fmt`。从子目录运行命令时，仍会使用解析到的 `rstack.config.*` 文件旁的缓存。stdin 格式化不会使用该缓存。
 
+使用 [`--cache-location <path>`](./cli/fmt#--cache-location-path) 可以将缓存保存到其他目录。相对路径基于当前工作目录解析。自定义目录会从文件发现中排除，但不会被 Git 自动忽略。
+
 使用 [`--no-cache`](./cli/fmt#--no-cache) 可以在运行时跳过缓存读取、创建和更新：
 
 ```bash