feat(format): add file-based root detection for formatter enabled checks (#76)

* feat(format): add file-based root detection for formatter enabled checks

* fix(format): correct findUp boundary and custom formatter signature

- Fix findUp to include stopDir in search (was skipping projectDir)
- Fix custom formatter enabled signature to match Info interface

* test(format): add tests for file-based root detection

- Add unit tests for formatter enabled detection
- Test biome detection in nested directories
- Test stopDir boundary condition (finding config at projectDir)
- Test custom formatter signature
- Add monorepo fixture structure for testing

Author: amondnet

packages/format/package.json

@@ -25,7 +25,7 @@
   ],
   "scripts": {
     "typecheck": "tsc -p tsconfig.json --noEmit",
-    "test": "echo 'No tests yet'"
+    "test": "bun test ./test"
   },
   "dependencies": {
     "@pleaseai/logger": "workspace:*",

packages/format/src/formatter.ts

@@ -6,7 +6,7 @@ export interface Info {
   command: string[]
   environment?: Record<string, string>
   extensions: string[]
-  enabled: (projectDir: string) => Promise<boolean>
+  enabled: (filePath: string, projectDir: string) => Promise<boolean>
 }
 
 /**
@@ -21,12 +21,17 @@ async function findUp(
   let currentDir = startDir
   const root = stopDir ?? path.parse(startDir).root
 
-  while (currentDir !== root && currentDir !== path.dirname(currentDir)) {
+  while (true) {
     const filePath = path.join(currentDir, filename)
     const file = Bun.file(filePath)
     if (await file.exists()) {
       results.push(filePath)
     }
+
+    // Stop if we've reached the stopDir or filesystem root
+    if (currentDir === root || currentDir === path.dirname(currentDir)) {
+      break
+    }
     currentDir = path.dirname(currentDir)
   }
 
@@ -41,7 +46,7 @@ export const gofmt: Info = {
   name: 'gofmt',
   command: ['gofmt', '-w', '$FILE'],
   extensions: ['.go'],
-  async enabled() {
+  async enabled(_filePath, _projectDir) {
     return Bun.which('gofmt') !== null
   },
 }
@@ -50,7 +55,7 @@ export const mix: Info = {
   name: 'mix',
   command: ['mix', 'format', '$FILE'],
   extensions: ['.ex', '.exs', '.eex', '.heex', '.leex', '.neex', '.sface'],
-  async enabled() {
+  async enabled(_filePath, _projectDir) {
     return Bun.which('mix') !== null
   },
 }
@@ -89,8 +94,9 @@ export const prettier: Info = {
     '.graphql',
     '.gql',
   ],
-  async enabled(projectDir: string) {
-    const items = await findUp('package.json', projectDir)
+  async enabled(filePath: string, projectDir: string) {
+    const startDir = path.dirname(filePath)
+    const items = await findUp('package.json', startDir, projectDir)
     for (const item of items) {
       const json = await Bun.file(item).json()
       if (json.dependencies?.prettier)
@@ -136,10 +142,11 @@ export const biome: Info = {
     '.graphql',
     '.gql',
   ],
-  async enabled(projectDir: string) {
+  async enabled(filePath: string, projectDir: string) {
+    const startDir = path.dirname(filePath)
     const configs = ['biome.json', 'biome.jsonc']
     for (const config of configs) {
-      const found = await findUp(config, projectDir)
+      const found = await findUp(config, startDir, projectDir)
       if (found.length > 0) {
         return true
       }
@@ -152,7 +159,7 @@ export const zig: Info = {
   name: 'zig',
   command: ['zig', 'fmt', '$FILE'],
   extensions: ['.zig', '.zon'],
-  async enabled() {
+  async enabled(_filePath, _projectDir) {
     return Bun.which('zig') !== null
   },
 }
@@ -161,8 +168,9 @@ export const clang: Info = {
   name: 'clang-format',
   command: ['clang-format', '-i', '$FILE'],
   extensions: ['.c', '.cc', '.cpp', '.cxx', '.c++', '.h', '.hh', '.hpp', '.hxx', '.h++', '.ino', '.C', '.H'],
-  async enabled(projectDir: string) {
-    const items = await findUp('.clang-format', projectDir)
+  async enabled(filePath: string, projectDir: string) {
+    const startDir = path.dirname(filePath)
+    const items = await findUp('.clang-format', startDir, projectDir)
     return items.length > 0
   },
 }
@@ -171,7 +179,7 @@ export const ktlint: Info = {
   name: 'ktlint',
   command: ['ktlint', '-F', '$FILE'],
   extensions: ['.kt', '.kts'],
-  async enabled() {
+  async enabled(_filePath, _projectDir) {
     return Bun.which('ktlint') !== null
   },
 }
@@ -180,12 +188,13 @@ export const ruff: Info = {
   name: 'ruff',
   command: ['ruff', 'format', '$FILE'],
   extensions: ['.py', '.pyi'],
-  async enabled(projectDir: string) {
+  async enabled(filePath: string, projectDir: string) {
     if (!Bun.which('ruff'))
       return false
+    const startDir = path.dirname(filePath)
     const configs = ['pyproject.toml', 'ruff.toml', '.ruff.toml']
     for (const config of configs) {
-      const found = await findUp(config, projectDir)
+      const found = await findUp(config, startDir, projectDir)
       const firstFound = found[0]
       if (firstFound) {
         if (config === 'pyproject.toml') {
@@ -200,7 +209,7 @@ export const ruff: Info = {
     }
     const deps = ['requirements.txt', 'pyproject.toml', 'Pipfile']
     for (const dep of deps) {
-      const found = await findUp(dep, projectDir)
+      const found = await findUp(dep, startDir, projectDir)
       const firstFound = found[0]
       if (firstFound) {
         const content = await Bun.file(firstFound).text()
@@ -216,7 +225,7 @@ export const rlang: Info = {
   name: 'air',
   command: ['air', 'format', '$FILE'],
   extensions: ['.R'],
-  async enabled() {
+  async enabled(_filePath, _projectDir) {
     const airPath = Bun.which('air')
     if (airPath == null)
       return false
@@ -245,8 +254,8 @@ export const uvformat: Info = {
   name: 'uv format',
   command: ['uv', 'format', '--', '$FILE'],
   extensions: ['.py', '.pyi'],
-  async enabled(projectDir: string) {
-    if (await ruff.enabled(projectDir))
+  async enabled(filePath: string, projectDir: string) {
+    if (await ruff.enabled(filePath, projectDir))
       return false
     if (Bun.which('uv') !== null) {
       const proc = Bun.spawn(['uv', 'format', '--help'], { stderr: 'pipe', stdout: 'pipe' })
@@ -261,7 +270,7 @@ export const rubocop: Info = {
   name: 'rubocop',
   command: ['rubocop', '--autocorrect', '$FILE'],
   extensions: ['.rb', '.rake', '.gemspec', '.ru'],
-  async enabled() {
+  async enabled(_filePath, _projectDir) {
     return Bun.which('rubocop') !== null
   },
 }
@@ -270,7 +279,7 @@ export const standardrb: Info = {
   name: 'standardrb',
   command: ['standardrb', '--fix', '$FILE'],
   extensions: ['.rb', '.rake', '.gemspec', '.ru'],
-  async enabled() {
+  async enabled(_filePath, _projectDir) {
     return Bun.which('standardrb') !== null
   },
 }
@@ -279,7 +288,7 @@ export const htmlbeautifier: Info = {
   name: 'htmlbeautifier',
   command: ['htmlbeautifier', '$FILE'],
   extensions: ['.erb', '.html.erb'],
-  async enabled() {
+  async enabled(_filePath, _projectDir) {
     return Bun.which('htmlbeautifier') !== null
   },
 }
@@ -288,7 +297,7 @@ export const dart: Info = {
   name: 'dart',
   command: ['dart', 'format', '$FILE'],
   extensions: ['.dart'],
-  async enabled() {
+  async enabled(_filePath, _projectDir) {
     return Bun.which('dart') !== null
   },
 }
@@ -297,10 +306,11 @@ export const ocamlformat: Info = {
   name: 'ocamlformat',
   command: ['ocamlformat', '-i', '$FILE'],
   extensions: ['.ml', '.mli'],
-  async enabled(projectDir: string) {
+  async enabled(filePath: string, projectDir: string) {
     if (!Bun.which('ocamlformat'))
       return false
-    const items = await findUp('.ocamlformat', projectDir)
+    const startDir = path.dirname(filePath)
+    const items = await findUp('.ocamlformat', startDir, projectDir)
     return items.length > 0
   },
 }
@@ -309,7 +319,7 @@ export const terraform: Info = {
   name: 'terraform',
   command: ['terraform', 'fmt', '$FILE'],
   extensions: ['.tf', '.tfvars'],
-  async enabled() {
+  async enabled(_filePath, _projectDir) {
     return Bun.which('terraform') !== null
   },
 }
@@ -318,7 +328,7 @@ export const latexindent: Info = {
   name: 'latexindent',
   command: ['latexindent', '-w', '-s', '$FILE'],
   extensions: ['.tex'],
-  async enabled() {
+  async enabled(_filePath, _projectDir) {
     return Bun.which('latexindent') !== null
   },
 }
@@ -327,7 +337,7 @@ export const gleam: Info = {
   name: 'gleam',
   command: ['gleam', 'format', '$FILE'],
   extensions: ['.gleam'],
-  async enabled() {
+  async enabled(_filePath, _projectDir) {
     return Bun.which('gleam') !== null
   },
 }
@@ -339,11 +349,12 @@ export const prisma: Info = {
     BUN_BE_BUN: '1',
   },
   extensions: ['.prisma'],
-  async enabled(projectDir: string) {
+  async enabled(filePath: string, projectDir: string) {
     // Check for schema.prisma or prisma/schema.prisma
+    const startDir = path.dirname(filePath)
     const schemaFiles = ['schema.prisma', 'prisma/schema.prisma']
     for (const schema of schemaFiles) {
-      const found = await findUp(schema, projectDir)
+      const found = await findUp(schema, startDir, projectDir)
       if (found.length > 0) {
         return true
       }

packages/format/src/index.ts

@@ -23,7 +23,7 @@ export interface FormatConfig {
 }
 
 interface State {
-  enabled: Record<string, boolean>
+  enabled: Record<string, boolean> // Cache key: `${dirPath}:${formatterName}`
   formatters: Record<string, Formatter.Info>
   projectDir: string
 }
@@ -86,7 +86,7 @@ function init(config: FormatConfig): void {
         name,
         command: item.command,
         extensions: item.extensions ?? [],
-        enabled: async () => true,
+        enabled: async (_filePath: string, _projectDir: string) => true,
       }
       if (item.environment)
         newFormatter.environment = item.environment
@@ -105,36 +105,39 @@ function getState(): State {
   return cachedState
 }
 
-async function isEnabled(item: Formatter.Info): Promise<boolean> {
+async function isEnabled(item: Formatter.Info, filePath: string): Promise<boolean> {
   const s = getState()
-  let status = s.enabled[item.name]
+  const dirPath = path.dirname(filePath)
+  const cacheKey = `${dirPath}:${item.name}`
+  let status = s.enabled[cacheKey]
   if (status === undefined) {
-    status = await item.enabled(s.projectDir)
-    s.enabled[item.name] = status
+    status = await item.enabled(filePath, s.projectDir)
+    s.enabled[cacheKey] = status
   }
   return status
 }
 
-async function getFormatter(ext: string): Promise<Formatter.Info[]> {
+async function getFormatter(ext: string, filePath: string): Promise<Formatter.Info[]> {
   const s = getState()
   const result: Formatter.Info[] = []
   for (const item of Object.values(s.formatters)) {
     log.debug({ name: item.name, ext }, 'checking formatter')
     if (!item.extensions.includes(ext))
       continue
-    if (!(await isEnabled(item)))
+    if (!(await isEnabled(item, filePath)))
       continue
     log.debug({ name: item.name, ext }, 'formatter enabled')
     result.push(item)
   }
   return result
 }
 
-async function status(): Promise<FormatStatus[]> {
+async function status(filePath?: string): Promise<FormatStatus[]> {
   const s = getState()
+  const testPath = filePath ?? s.projectDir
   const result: FormatStatus[] = []
   for (const formatter of Object.values(s.formatters)) {
-    const enabled = await isEnabled(formatter)
+    const enabled = await isEnabled(formatter, testPath)
     result.push({
       name: formatter.name,
       extensions: formatter.extensions,
@@ -152,7 +155,7 @@ async function formatFile(file: string): Promise<boolean> {
   const ext = path.extname(file)
   log.debug({ file, ext }, 'formatting file')
 
-  const formatters = await getFormatter(ext)
+  const formatters = await getFormatter(ext, file)
   if (formatters.length === 0) {
     log.debug({ ext }, 'no formatter found')
     return false

packages/format/test/fixtures/monorepo/biome.json

@@ -0,0 +1,3 @@
+{
+  "$schema": "https://biomejs.dev/schemas/1.9.4/schema.json"
+}

packages/format/test/fixtures/monorepo/packages/backend/src/server.py

@@ -0,0 +1,2 @@
+# Test file - no formatter config in backend
+print("hello")

packages/format/test/fixtures/monorepo/packages/frontend/biome.json

@@ -0,0 +1,3 @@
+{
+  "$schema": "https://biomejs.dev/schemas/1.9.4/schema.json"
+}

packages/format/test/fixtures/monorepo/packages/frontend/src/app.ts

@@ -0,0 +1,2 @@
+// Test file for formatter detection
+export const hello = 'world'