feat: Add --prune option to prevent walking subtrees

src/files/deno.test.ts

@@ -12,9 +12,11 @@ await requestReadPermission()
 // Use this file for testing file behavior
 const testUrl = import.meta.url
 const testPath = fromFileUrl(testUrl)
-const testDir = dirname(testPath)
+const testDir = dirname(testPath) // $REPO/src/files
 const testFilename = basename(testPath)
+const repoRoot = dirname(dirname(dirname(testPath)))
 const ignore = new FileIgnoreRules([])
+const prune = new FileIgnoreRules(['derivatives'], false)
 
 Deno.test('Deno implementation of BIDSFile', async (t) => {
   await t.step('implements basic file properties', () => {
@@ -53,7 +55,7 @@ Deno.test('Deno implementation of BIDSFile', async (t) => {
     'strips BOM characters when reading UTF-8 via .text()',
     async () => {
       // BOM is invalid in JSON but shows up often from certain tools, so abstract handling it
-      const bomDir = join(testPath, '..', '..', 'tests')
+      const bomDir = join(repoRoot, 'src', 'tests')
       const bomFilename = 'bom-utf8.json'
       const file = new BIDSFileDeno(bomDir, bomFilename, ignore)
       const text = await file.text()
@@ -75,4 +77,16 @@ Deno.test('Deno implementation of FileTree', async (t) => {
     assert(testObj !== undefined)
     assertEquals(testObj.path, `/${parent}/${testFilename}`)
   })
+
+  await t.step('implements pruning', async () => {
+    const dsDir = join(repoRoot, 'tests', 'data', 'valid_dataset')
+    const derivFile =
+      'derivatives/fmriprep/sub-01/ses-01/func/sub-01_ses-01_task-rest_confounds.tsv.gz'
+
+    const fullTree = await readFileTree(dsDir)
+    assert(fullTree.get(derivFile))
+
+    const prunedTree = await readFileTree(dsDir, prune)
+    assert(!prunedTree.get(derivFile))
+  })
 })

src/files/deno.ts

@@ -117,17 +117,22 @@ async function _readFileTree(
   rootPath: string,
   relativePath: string,
   ignore: FileIgnoreRules,
+  prune: FileIgnoreRules,
   parent?: FileTree,
 ): Promise<FileTree> {
   await requestReadPermission()
   const name = basename(relativePath)
   const tree = new FileTree(relativePath, name, parent, ignore)
 
   for await (const dirEntry of Deno.readDir(join(rootPath, relativePath))) {
+    const thisPath = posix.join(relativePath, dirEntry.name)
+    if (prune.test(thisPath)) {
+      continue
+    }
     if (dirEntry.isFile || dirEntry.isSymlink) {
       const file = new BIDSFileDeno(
         rootPath,
-        posix.join(relativePath, dirEntry.name),
+        thisPath,
         ignore,
       )
       file.parent = tree
@@ -136,8 +141,9 @@ async function _readFileTree(
     if (dirEntry.isDirectory) {
       const dirTree = await _readFileTree(
         rootPath,
-        posix.join(relativePath, dirEntry.name),
+        thisPath,
         ignore,
+        prune,
         tree,
       )
       tree.directories.push(dirTree)
@@ -149,9 +155,13 @@ async function _readFileTree(
 /**
  * Read in the target directory structure and return a FileTree
  */
-export async function readFileTree(rootPath: string): Promise<FileTree> {
+export async function readFileTree(
+  rootPath: string,
+  prune?: FileIgnoreRules,
+): Promise<FileTree> {
+  prune ??= new FileIgnoreRules([], false)
   const ignore = new FileIgnoreRules([])
-  const tree = await _readFileTree(rootPath, '/', ignore)
+  const tree = await _readFileTree(rootPath, '/', ignore, prune)
   const bidsignore = tree.get('.bidsignore')
   if (bidsignore) {
     try {

src/files/ignore.ts

@@ -27,10 +27,15 @@ const defaultIgnores = [
 export class FileIgnoreRules {
   #ignore: Ignore
 
-  constructor(config: string[]) {
+  constructor(
+    config: string[],
+    addDefaults: boolean = true,
+  ) {
     // @ts-expect-error
     this.#ignore = ignore()
-    this.#ignore.add(defaultIgnores)
+    if (addDefaults) {
+      this.#ignore.add(defaultIgnores)
+    }
     this.#ignore.add(config)
   }
 

src/main.ts

@@ -3,6 +3,7 @@ import type { Config } from './setup/options.ts'
 import * as colors from '@std/fmt/colors'
 import { readFileTree } from './files/deno.ts'
 import { fileListToTree } from './files/browser.ts'
+import { FileIgnoreRules } from './files/ignore.ts'
 import { resolve } from '@std/path'
 import { validate } from './validators/bids.ts'
 import { consoleFormat, resultToJSONStr } from './utils/output.ts'
@@ -21,7 +22,10 @@ export async function main(): Promise<ValidationResult> {
   setupLogging(options.debug)
 
   const absolutePath = resolve(options.datasetPath)
-  const tree = await readFileTree(absolutePath)
+  const prune = options.prune
+    ? new FileIgnoreRules(['derivatives', 'sourcedata', 'code'], false)
+    : null
+  const tree = await readFileTree(absolutePath, prune)
 
   const config = options.config ? JSON.parse(Deno.readTextFileSync(options.config)) as Config : {}
 

src/setup/options.ts

@@ -29,6 +29,7 @@ export type ValidatorOptions = {
   recursive?: boolean
   outfile?: string
   blacklistModalities: string[]
+  prune?: boolean
 }
 
 const modalityType = new EnumType<string>(
@@ -72,6 +73,10 @@ export const validateCommand: Command<void, void, any, string[], void> = new Com
     '-r, --recursive',
     'Validate datasets found in derivatives directories in addition to root dataset',
   )
+  .option(
+    '-p, --prune',
+    'Prune derivatives and sourcedata directories on load (disables -r and will underestimate dataset size)',
+  )
   .option(
     '-o, --outfile <file:string>',
     'File to write validation results to.',

src/tests/regression.test.ts

@@ -3,13 +3,12 @@ import { pathsToTree } from '../files/filetree.ts'
 import { validate } from '../validators/bids.ts'
 import type { BIDSFile } from '../types/filetree.ts'
 
-
 Deno.test('Regression tests', async (t) => {
   await t.step('Verify ignored files in scans.tsv do not trigger error', async () => {
     const paths = [
       '/dataset_description.json',
       '/sub-01/anat/sub-01_T1w.nii.gz',
-      '/sub-01/anat/sub-01_CT.nii.gz',  // unknown file
+      '/sub-01/anat/sub-01_CT.nii.gz', // unknown file
       '/sub-01/sub-01_scans.tsv',
     ]
     const ignore = ['*_CT.nii.gz']