#59: fixes escaped range notation

index.js

@@ -5,6 +5,8 @@ function makeArray (subject) {
     : [subject]
 }
 
+const EMPTY = ''
+const ESCAPE = '\\'
 const REGEX_TEST_BLANK_LINE = /^\s+$/
 const REGEX_REPLACE_LEADING_EXCAPED_EXCLAMATION = /^\\!/
 const REGEX_REPLACE_LEADING_EXCAPED_HASH = /^\\#/
@@ -35,7 +37,7 @@ const sanitizeRange = range => range.replace(
     ? match
     // Invalid range (out of order) which is ok for gitignore rules but
     //   fatal for JavaScript regular expression, so eliminate it.
-    : ''
+    : EMPTY
 )
 
 // > If the pattern ends with a slash,
@@ -59,7 +61,7 @@ const REPLACERS = [
     /\\?\s+$/,
     match => match.indexOf('\\') === 0
       ? ' '
-      : ''
+      : EMPTY
   ],
 
   // replace (\ ) with ' '
@@ -86,19 +88,10 @@ const REPLACERS = [
   // > - the opening curly brace {,
   // > These special characters are often called "metacharacters".
   [
-    /[\\^$.|*+(){]/g,
+    /[\\$.|*+(){^]/g,
     match => `\\${match}`
   ],
 
-  [
-    // > [abc] matches any character inside the brackets
-    // >    (in this case a, b, or c);
-    /\[([^\]/]*)($|\])/g,
-    (match, p1, p2) => p2 === ']'
-      ? `[${sanitizeRange(p1)}]`
-      : `\\${match}`
-  ],
-
   [
     // > a question mark (?) matches a single character
     /(?!\\)\?/g,
@@ -134,31 +127,6 @@ const REPLACERS = [
     () => '^(?:.*\\/)?'
   ],
 
-  // ending
-  [
-    // 'js' will not match 'js.'
-    // 'ab' will not match 'abc'
-    /(?:[^*])$/,
-
-    // WTF!
-    // https://git-scm.com/docs/gitignore
-    // changes in [2.22.1](https://git-scm.com/docs/gitignore/2.22.1)
-    // which re-fixes #24, #38
-
-    // > If there is a separator at the end of the pattern then the pattern
-    // > will only match directories, otherwise the pattern can match both
-    // > files and directories.
-
-    // 'js*' will not match 'a.js'
-    // 'js/' will not match 'a.js'
-    // 'js' will match 'a.js' and 'a.js/'
-    match => /\/$/.test(match)
-      // foo/ will not match 'foo'
-      ? `${match}$`
-      // foo matches 'foo' and 'foo/'
-      : `${match}(?=$|\\/$)`
-  ],
-
   // starting
   [
     // there will be no leading '/'
@@ -227,13 +195,73 @@ const REPLACERS = [
     (_, p1) => `${p1}[^\\/]*`
   ],
 
+  [
+    // unescape, revert step 3 except for back slash
+    // For example, if a user escape a '\\*',
+    // after step 3, the result will be '\\\\\\*'
+    /\\\\\\(?=[$.|*+(){^])/g,
+    () => ESCAPE
+  ],
+
+  [
+    // '\\\\' -> '\\'
+    /\\\\/g,
+    () => ESCAPE
+  ],
+
+  [
+    // > The range notation, e.g. [a-zA-Z],
+    // > can be used to match one of the characters in a range.
+
+    // `\` is escaped by step 3
+    /(\\)?\[([^\]/]*?)(\\*)($|\])/g,
+    (match, leadEscape, range, endEscape, close) => leadEscape === ESCAPE
+      // '\\[bar]' -> '\\\\[bar\\]'
+      ? `\\[${range}${close}`
+      : close === ']'
+        ? endEscape.length % 2 === 0
+          // A normal case, and it is a range notation
+          // '[bar]'
+          // '[bar\\\\]'
+          ? `[${sanitizeRange(range)}${endEscape}]`
+          // Invalid range notaton
+          // '[bar\\]' -> '[bar\\\\]'
+          : '[]'
+        : '[]'
+  ],
+
+  // ending
+  [
+    // 'js' will not match 'js.'
+    // 'ab' will not match 'abc'
+    /(?:[^*])$/,
+
+    // WTF!
+    // https://git-scm.com/docs/gitignore
+    // changes in [2.22.1](https://git-scm.com/docs/gitignore/2.22.1)
+    // which re-fixes #24, #38
+
+    // > If there is a separator at the end of the pattern then the pattern
+    // > will only match directories, otherwise the pattern can match both
+    // > files and directories.
+
+    // 'js*' will not match 'a.js'
+    // 'js/' will not match 'a.js'
+    // 'js' will match 'a.js' and 'a.js/'
+    match => /\/$/.test(match)
+      // foo/ will not match 'foo'
+      ? `${match}$`
+      // foo matches 'foo' and 'foo/'
+      : `${match}(?=$|\\/$)`
+  ],
+
   // trailing wildcard
   [
     /(\^|\\\/)?\\\*$/,
     (_, p1) => {
       const prefix = p1
         // '\^':
-        // '/*' does not match ''
+        // '/*' does not match EMPTY
         // '/*' does not match everything
 
         // '\\\/':
@@ -247,12 +275,6 @@ const REPLACERS = [
       return `${prefix}(?=$|\\/$)`
     }
   ],
-
-  [
-    // unescape
-    /\\\\\\/g,
-    () => '\\'
-  ]
 ]
 
 // A simple cache, because an ignore rule only has only one certain meaning
@@ -345,7 +367,7 @@ const checkPath = (path, originalPath, doThrow) => {
     )
   }
 
-  // We don't know if we should ignore '', so throw
+  // We don't know if we should ignore EMPTY, so throw
   if (!path) {
     return doThrow(`path must not be empty`, TypeError)
   }

test/fixtures/cases.js

@@ -12,19 +12,63 @@ const cases = [
   // [
   //   'Example',
   //   [
+  //     // ignore pattern
   //     'a'
   //   ],
   //   {
+  //     // 1 indicates 'a' should be ignored
   //     'a': 1
   //   }
   // ],
   [
-    '#59',
+    '#59 and more cases about range notation',
     [
-      'src/\\[app\\]'
+      'src/\\[foo\\]',
+      'src/\\[foo2\\\\]',
+      'src/\\[foo3\\\\\\]',
+      'src/\\[foo4\\\\\\\\]',
+      'src/\\[foo5\\\\\\\\\\]',
+      'src/\\[foo6\\\\\\\\\\\\]',
+
+      'src/\\[bar]',
+
+      'src/[e\\\\]',
+      's/[f\\\\\\\\]',
+
+      's/[a-z0-9]',
+
+      // The following special cases are not described in gitignore manual
+      'src/[q',
+      'src/\\[u',
+      'src/[x\\]'
     ],
     {
-      'src/[app]': 1
+      // 'src/[foo]': 1,
+      // 'src/[foo2\\]': 1,
+
+      // // Seems the followings are side-effects,
+      // // however, we will implement these
+      // 'src/[foo3\\]': 1,
+      // 'src/[foo4\\\\]': 1,
+      // 'src/[foo5\\\\]': 1,
+      // 'src/[foo6\\\\\\]': 1,
+
+      'src/[bar]': 1,
+
+      'src/e': 1,
+      'src/\\': 1,
+      's/f': 1,
+      's/\\': 1,
+
+      's/a': 1,
+
+      's/0': 1,
+
+      'src/[q': 0,
+      'src/[u': 1,
+      'src/[x': 0,
+      'src/[x]': 0,
+      'src/x': 0
     }
   ],
   [