Add magicalBraces option

This tells hasMagic to treat brace expansion as magical.

Fix: #496

PR-URL: #499
Credit: @isaacs
Close: #499
Reviewed-by: @isaacs

README.md

@@ -129,11 +129,14 @@ if they're not consumed immediately.
 Returns `true` if the provided pattern contains any "magic" glob
 characters, given the options provided.
 
-Note that brace expansion is not considered "magic", as that just
-turns one string into an array of strings. So a pattern like
-`'x{a,b}y'` would return `false`, because `'xay'` and `'xby'`
-both do not contain any magic glob characters, and it's treated
-the same as if you had called it on `['xay', 'xby']`.
+Brace expansion is not considered "magic" unless the
+`magicalBraces` option is set, as brace expansion just turns one
+string into an array of strings. So a pattern like `'x{a,b}y'`
+would return `false`, because `'xay'` and `'xby'` both do not
+contain any magic glob characters, and it's treated the same as
+if you had called it on `['xay', 'xby']`. When
+`magicalBraces:true` is in the options, brace expansion _is_
+treated as a pattern having magic.
 
 ## Class `Glob`
 
@@ -244,6 +247,12 @@ share the previously loaded cache.
   matches. Note that an explicit dot in a portion of the pattern
   will always match dot files.
 
+- `magicalBraces` Treat brace expansion like `{a,b}` as a "magic"
+  pattern. Has no effect if {@link nobrace} is set.
+
+  Only has effect on the {@link hasMagic} function, no effect on
+  glob pattern matching itself.
+
 - `mark` Add a `/` character to directory matches. Note that this
   requires additional stat calls.
 

changelog.md

@@ -6,6 +6,8 @@
   relative paths. An unset `absolute` setting will still return
   absolute or relative paths based on whether the pattern is
   absolute.
+- Add `magicalBraces` option to treat brace expansion as "magic"
+  in the `hasMagic` function.
 
 ## 9.0
 

src/glob.ts

@@ -93,6 +93,14 @@ export interface GlobOptions {
    */
   ignore?: string | string[] | Ignore
 
+  /**
+   * Treat brace expansion like `{a,b}` as a "magic" pattern. Has no
+   * effect if {@link nobrace} is set.
+   *
+   * Only has effect on the {@link hasMagic} function.
+   */
+  magicalBraces?: boolean
+
   /**
    * Add a `/` character to directory matches. Note that this requires
    * additional stat calls in some cases.
@@ -263,7 +271,8 @@ export class Glob<Opts extends GlobOptions> implements GlobOptions {
   dot: boolean
   follow: boolean
   ignore?: Ignore
-  mark: boolean
+  magicalBraces: boolean
+  mark?: boolean
   matchBase: boolean
   nobrace: boolean
   nocase: boolean
@@ -314,6 +323,7 @@ export class Glob<Opts extends GlobOptions> implements GlobOptions {
     }
     this.cwd = opts.cwd || ''
     this.root = opts.root
+    this.magicalBraces = !!opts.magicalBraces
     this.nobrace = !!opts.nobrace
     this.noext = !!opts.noext
     this.realpath = !!opts.realpath

src/has-magic.ts

@@ -2,7 +2,15 @@ import { Glob, GlobOptions } from './glob.js'
 
 /**
  * Return true if the patterns provided contain any magic
- * glob characters.
+ * glob characters, given the options provided.
+ *
+ * Brace expansion is not considered "magic" unless the `magicalBraces` option
+ * is set, as brace expansion just turns one string into an array of strings.
+ * So a pattern like `'x{a,b}y'` would return `false`, because `'xay'` and
+ * `'xby'` both do not contain any magic glob characters, and it's treated the
+ * same as if you had called it on `['xay', 'xby']`. When
+ * `magicalBraces:true` is in the options, brace expansion _is_ treated as a
+ * pattern having magic.
  */
 export const hasMagic = (
   pattern: string | string[],
@@ -11,8 +19,10 @@ export const hasMagic = (
   if (!Array.isArray(pattern)) {
     pattern = [pattern]
   }
+  const length = pattern.length
   const g = new Glob(pattern, options)
-  return g.patterns.length === 0
-    ? false
-    : g.patterns.some(p => p.hasMagic())
+  if (g.magicalBraces && g.patterns.length !== length) {
+    return true
+  }
+  return g.patterns.some(p => p.hasMagic())
 }

test/has-magic.ts

@@ -23,8 +23,16 @@ t.test('detect magic in glob patterns', async t => {
     'no magic in a/b/+(x|y) noext'
   )
   t.notOk(glob.hasMagic('{a,b}'), 'no magic in {a,b}')
+  t.ok(
+    glob.hasMagic('{a,b}', { magicalBraces: true }),
+    'magical braces are magic in {a,b}'
+  )
   t.notOk(
     glob.hasMagic('{a,b}', { nobrace: true }),
     'no magic in {a,b} nobrace:true'
   )
+  t.notOk(
+    glob.hasMagic('{a,b}', { nobrace: true, magicalBraces: true }),
+    'magical braces not magic in {a,b} nobrace:true'
+  )
 })