Allow isIgnored to un-ignore results by returning token

.eslintrc.json

@@ -62,7 +62,7 @@
     "no-irregular-whitespace": 2,
     "no-iterator": 2,
     "no-label-var": 2,
-    "no-labels": 2,
+    "no-labels": 0,
     "no-lone-blocks": 2,
     "no-lonely-if": 2,
     "no-mixed-spaces-and-tabs": 2,

README.md

@@ -474,6 +474,8 @@ isMatch('bar');
 isMatch('baz');
 ```
 
+Return `picomatch.constants.UNIGNORE` from `onIgnore` to un-ignore the result.
+
 #### options.onResult
 
 ```js

lib/constants.js

@@ -3,6 +3,8 @@
 const WIN_SLASH = '\\\\/';
 const WIN_NO_SLASH = `[^${WIN_SLASH}]`;
 
+const UNIGNORE = Symbol('unignore');
+
 /**
  * Posix glob regex
  */
@@ -89,6 +91,9 @@ module.exports = {
   MAX_LENGTH: 1024 * 64,
   POSIX_REGEX_SOURCE,
 
+  // token to un-ignore results in onIgnore
+  UNIGNORE,
+
   // regular expressions
   REGEX_BACKSLASH: /\\(?![*+?^${}(|)[\]])/g,
   REGEX_NON_SPECIAL_CHARS: /^[^@![\].,$*+?^{}()|\\/]+/,

lib/picomatch.js

@@ -75,12 +75,17 @@ const picomatch = (glob, options, returnState = false) => {
       return returnObject ? result : false;
     }
 
-    if (isIgnored(input)) {
-      if (typeof opts.onIgnore === 'function') {
-        opts.onIgnore(result);
+    ignored: {
+      if (isIgnored(input)) {
+        if (typeof opts.onIgnore === 'function') {
+          if (opts.onIgnore(result) === constants.UNIGNORE) {
+            result.isMatch = true;
+            break ignored;
+          }
+        }
+        result.isMatch = false;
+        return returnObject ? result : false;
       }
-      result.isMatch = false;
-      return returnObject ? result : false;
     }
 
     if (typeof opts.onMatch === 'function') {

test/options.onIgnore.js

@@ -0,0 +1,69 @@
+'use strict';
+
+const assert = require('assert');
+const match = require('./support/match');
+const picomatch = require('..');
+const { isMatch } = picomatch;
+
+const equal = (actual, expected, msg) => {
+  assert.deepStrictEqual([].concat(actual).sort(), [].concat(expected).sort(), msg);
+};
+
+describe('options.onIgnore', () => {
+  it('should call options.onIgnore on each ignored string', () => {
+    const ignored = [];
+
+    const options = {
+      ignore: ['b/*', 'b/*/*'],
+      onIgnore({ pattern, regex, input, output }) {
+        ignored.push(input);
+      }
+    };
+
+    const fixtures = ['a', 'b', 'b/a', 'b/b', 'b/a/a'];
+
+    equal(match(fixtures, '**', options), ['a', 'b']);
+    equal(ignored.length, 3);
+  });
+
+  it('should allow to un-ignore from options.onIgnore', () => {
+    const options = (ignore, unignore) => {
+      return {
+        ignore,
+        onIgnore({ pattern, regex, input, output }) {
+          if (unignore) return isMatch(input, unignore) && picomatch.constants.UNIGNORE;
+        }
+      };
+    };
+
+    const fixtures = ['a', 'b', 'b/a', 'b/b', 'b/a/a'];
+
+    equal(match(fixtures, '**', options(['b/*', 'b/*/*'])), ['a', 'b']);
+    equal(match(fixtures, '**', options(['b/*', 'b/*/*'], ['b/a'])), ['a', 'b', 'b/a']);
+    equal(match(fixtures, '**', options(['b/*', 'b/*/*'], ['b/a/a'])), ['a', 'b', 'b/a/a']);
+    equal(match(fixtures, '**', options(['b/*', 'b/*/*'], ['b/*'])), ['a', 'b', 'b/a', 'b/b']);
+    equal(match(fixtures, '**', options(['b/*', 'b/*/*'], ['*/a'])), ['a', 'b', 'b/a']);
+    equal(match(fixtures, '**', options([], ['**'])), ['a', 'b', 'b/a', 'b/b', 'b/a/a']);
+  });
+
+  it('should call onMatch for un-ignored results', () => {
+    const patterns = [];
+
+    const options = (ignore, unignore) => {
+      return {
+        ignore,
+        onIgnore({ pattern, regex, input, output }) {
+          if (unignore) return isMatch(input, unignore) && picomatch.constants.UNIGNORE;
+        },
+        onMatch({ pattern, regex, input, output }, matches) {
+          patterns.push(output);
+        }
+      };
+    };
+
+    const fixtures = ['a', 'b', 'b/a', 'b/b', 'b/a/a'];
+
+    equal(match(fixtures, '**', options(['b/a**'], ['b/a/a'])), ['a', 'b', 'b/b', 'b/a/a']);
+    equal(patterns, ['a', 'b', 'b/b', 'b/a/a']);
+  });
+});