Update MD051/link-fragments to handle backslash-escaped content in link and definition destinations (fixes #956).

lib/md051.js

@@ -15,11 +15,15 @@ const anchorRe = /\{(#[a-z\d]+(?:[-_][a-z\d]+)*)\}/gu;
 const childrenExclude = new Set([ "image", "reference", "resource" ]);
 const tokensInclude = new Set([ "codeTextData", "data" ]);
 
+/**
+ * @typedef {import("../helpers/micromark.cjs").Token} Token
+ */
+
 /**
  * Converts a Markdown heading into an HTML fragment according to the rules
  * used by GitHub.
  *
- * @param {Object} headingText Heading text token.
+ * @param {Token} headingText Heading text token.
  * @returns {string} Fragment string for heading.
  */
 function convertHeadingToHTMLFragment(headingText) {
@@ -46,6 +50,18 @@ function convertHeadingToHTMLFragment(headingText) {
   );
 }
 
+/**
+ * Unescapes the text of a String-type micromark Token.
+ *
+ * @param {Token} token String-type micromark Token.
+ * @returns {string} Unescaped token text.
+ */
+function unescapeStringTokenText(token) {
+  return filterByTypes(token.children, [ "characterEscapeValue", "data" ])
+    .map((child) => child.text)
+    .join("");
+}
+
 module.exports = {
   "names": [ "MD051", "link-fragments" ],
   "description": "Link fragments should be valid",
@@ -99,7 +115,8 @@ module.exports = {
       for (const link of links) {
         const definitions = filterByTypes(link.children, [ definitionType ]);
         for (const definition of definitions) {
-          const { endColumn, startColumn, text } = definition;
+          const { endColumn, startColumn } = definition;
+          const text = unescapeStringTokenText(definition);
           if (
             (text.length > 1) &&
             text.startsWith("#") &&

test/link-fragments.md

@@ -64,6 +64,10 @@
 
 [Valid](#valid-heading-has-)
 
+[Valid](#valid_heading-escaped_underscores)
+
+[Valid](#valid\_heading\-escaped\_underscores)
+
 [Valid](#namedlink)
 
 [Valid](#idlink)
@@ -78,6 +82,8 @@
 
 [Valid][goodref]
 
+[Valid][escapedref]
+
 ### Valid H3 Heading
 
 Text
@@ -159,6 +165,8 @@ Text
 
 ### Valid Heading Has ![an Image](https://example.com)
 
+### Valid_Heading Escaped_Underscores
+
 <a name="namedlink"></a>
 
 <a id = idlink></a>
@@ -177,6 +185,8 @@ Text
 
 [goodref]: #namedlink
 
+[escapedref]: #valid\_heading\-escaped\_underscores
+
 ## Invalid Fragments
 
 [Invalid](#valid-heading-is-an-image) {MD051}

test/snapshots/markdownlint-test-scenarios.js.md

@@ -23969,7 +23969,7 @@ Generated by [AVA](https://avajs.dev).
             37,
           ],
           fixInfo: null,
-          lineNumber: 182,
+          lineNumber: 192,
           ruleDescription: 'Link fragments should be valid',
           ruleInformation: 'https://github.com/DavidAnson/markdownlint/blob/v0.0.0/doc/md051.md',
           ruleNames: [
@@ -23985,7 +23985,7 @@ Generated by [AVA](https://avajs.dev).
             31,
           ],
           fixInfo: null,
-          lineNumber: 184,
+          lineNumber: 194,
           ruleDescription: 'Link fragments should be valid',
           ruleInformation: 'https://github.com/DavidAnson/markdownlint/blob/v0.0.0/doc/md051.md',
           ruleNames: [
@@ -24001,7 +24001,7 @@ Generated by [AVA](https://avajs.dev).
             36,
           ],
           fixInfo: null,
-          lineNumber: 186,
+          lineNumber: 196,
           ruleDescription: 'Link fragments should be valid',
           ruleInformation: 'https://github.com/DavidAnson/markdownlint/blob/v0.0.0/doc/md051.md',
           ruleNames: [
@@ -24017,7 +24017,7 @@ Generated by [AVA](https://avajs.dev).
             28,
           ],
           fixInfo: null,
-          lineNumber: 188,
+          lineNumber: 198,
           ruleDescription: 'Link fragments should be valid',
           ruleInformation: 'https://github.com/DavidAnson/markdownlint/blob/v0.0.0/doc/md051.md',
           ruleNames: [
@@ -24033,7 +24033,7 @@ Generated by [AVA](https://avajs.dev).
             18,
           ],
           fixInfo: null,
-          lineNumber: 190,
+          lineNumber: 200,
           ruleDescription: 'Link fragments should be valid',
           ruleInformation: 'https://github.com/DavidAnson/markdownlint/blob/v0.0.0/doc/md051.md',
           ruleNames: [
@@ -24053,7 +24053,7 @@ Generated by [AVA](https://avajs.dev).
             editColumn: 11,
             insertText: '#HREFandID',
           },
-          lineNumber: 192,
+          lineNumber: 202,
           ruleDescription: 'Link fragments should be valid',
           ruleInformation: 'https://github.com/DavidAnson/markdownlint/blob/v0.0.0/doc/md051.md',
           ruleNames: [
@@ -24069,7 +24069,7 @@ Generated by [AVA](https://avajs.dev).
             34,
           ],
           fixInfo: null,
-          lineNumber: 194,
+          lineNumber: 204,
           ruleDescription: 'Link fragments should be valid',
           ruleInformation: 'https://github.com/DavidAnson/markdownlint/blob/v0.0.0/doc/md051.md',
           ruleNames: [
@@ -24085,7 +24085,7 @@ Generated by [AVA](https://avajs.dev).
             34,
           ],
           fixInfo: null,
-          lineNumber: 196,
+          lineNumber: 206,
           ruleDescription: 'Link fragments should be valid',
           ruleInformation: 'https://github.com/DavidAnson/markdownlint/blob/v0.0.0/doc/md051.md',
           ruleNames: [
@@ -24101,7 +24101,7 @@ Generated by [AVA](https://avajs.dev).
             39,
           ],
           fixInfo: null,
-          lineNumber: 198,
+          lineNumber: 208,
           ruleDescription: 'Link fragments should be valid',
           ruleInformation: 'https://github.com/DavidAnson/markdownlint/blob/v0.0.0/doc/md051.md',
           ruleNames: [
@@ -24114,7 +24114,7 @@ Generated by [AVA](https://avajs.dev).
           errorDetail: null,
           errorRange: null,
           fixInfo: null,
-          lineNumber: 200,
+          lineNumber: 210,
           ruleDescription: 'Link fragments should be valid',
           ruleInformation: 'https://github.com/DavidAnson/markdownlint/blob/v0.0.0/doc/md051.md',
           ruleNames: [
@@ -24130,7 +24130,7 @@ Generated by [AVA](https://avajs.dev).
             28,
           ],
           fixInfo: null,
-          lineNumber: 205,
+          lineNumber: 215,
           ruleDescription: 'Link fragments should be valid',
           ruleInformation: 'https://github.com/DavidAnson/markdownlint/blob/v0.0.0/doc/md051.md',
           ruleNames: [
@@ -24150,7 +24150,7 @@ Generated by [AVA](https://avajs.dev).
             editColumn: 9,
             insertText: '#valid-fragments',
           },
-          lineNumber: 209,
+          lineNumber: 219,
           ruleDescription: 'Link fragments should be valid',
           ruleInformation: 'https://github.com/DavidAnson/markdownlint/blob/v0.0.0/doc/md051.md',
           ruleNames: [
@@ -24170,7 +24170,7 @@ Generated by [AVA](https://avajs.dev).
             editColumn: 12,
             insertText: '#namedlink',
           },
-          lineNumber: 211,
+          lineNumber: 221,
           ruleDescription: 'Link fragments should be valid',
           ruleInformation: 'https://github.com/DavidAnson/markdownlint/blob/v0.0.0/doc/md051.md',
           ruleNames: [
@@ -24183,7 +24183,7 @@ Generated by [AVA](https://avajs.dev).
           errorDetail: 'Expected: #namedlink; Actual: #NAMEDLINK',
           errorRange: null,
           fixInfo: null,
-          lineNumber: 213,
+          lineNumber: 223,
           ruleDescription: 'Link fragments should be valid',
           ruleInformation: 'https://github.com/DavidAnson/markdownlint/blob/v0.0.0/doc/md051.md',
           ruleNames: [
@@ -24203,7 +24203,7 @@ Generated by [AVA](https://avajs.dev).
             editColumn: 13,
             insertText: '#idlink',
           },
-          lineNumber: 218,
+          lineNumber: 228,
           ruleDescription: 'Link fragments should be valid',
           ruleInformation: 'https://github.com/DavidAnson/markdownlint/blob/v0.0.0/doc/md051.md',
           ruleNames: [
@@ -24219,7 +24219,7 @@ Generated by [AVA](https://avajs.dev).
             26,
           ],
           fixInfo: null,
-          lineNumber: 253,
+          lineNumber: 263,
           ruleDescription: 'Link fragments should be valid',
           ruleInformation: 'https://github.com/DavidAnson/markdownlint/blob/v0.0.0/doc/md051.md',
           ruleNames: [
@@ -24235,7 +24235,7 @@ Generated by [AVA](https://avajs.dev).
             26,
           ],
           fixInfo: null,
-          lineNumber: 255,
+          lineNumber: 265,
           ruleDescription: 'Link fragments should be valid',
           ruleInformation: 'https://github.com/DavidAnson/markdownlint/blob/v0.0.0/doc/md051.md',
           ruleNames: [
@@ -24251,7 +24251,7 @@ Generated by [AVA](https://avajs.dev).
             20,
           ],
           fixInfo: null,
-          lineNumber: 257,
+          lineNumber: 267,
           ruleDescription: 'Link fragments should be valid',
           ruleInformation: 'https://github.com/DavidAnson/markdownlint/blob/v0.0.0/doc/md051.md',
           ruleNames: [
@@ -24267,7 +24267,7 @@ Generated by [AVA](https://avajs.dev).
             23,
           ],
           fixInfo: null,
-          lineNumber: 259,
+          lineNumber: 269,
           ruleDescription: 'Link fragments should be valid',
           ruleInformation: 'https://github.com/DavidAnson/markdownlint/blob/v0.0.0/doc/md051.md',
           ruleNames: [
@@ -24283,7 +24283,7 @@ Generated by [AVA](https://avajs.dev).
             22,
           ],
           fixInfo: null,
-          lineNumber: 261,
+          lineNumber: 271,
           ruleDescription: 'Link fragments should be valid',
           ruleInformation: 'https://github.com/DavidAnson/markdownlint/blob/v0.0.0/doc/md051.md',
           ruleNames: [
@@ -24299,7 +24299,7 @@ Generated by [AVA](https://avajs.dev).
             42,
           ],
           fixInfo: null,
-          lineNumber: 263,
+          lineNumber: 273,
           ruleDescription: 'Link fragments should be valid',
           ruleInformation: 'https://github.com/DavidAnson/markdownlint/blob/v0.0.0/doc/md051.md',
           ruleNames: [
@@ -24315,7 +24315,7 @@ Generated by [AVA](https://avajs.dev).
             21,
           ],
           fixInfo: null,
-          lineNumber: 265,
+          lineNumber: 275,
           ruleDescription: 'Link fragments should be valid',
           ruleInformation: 'https://github.com/DavidAnson/markdownlint/blob/v0.0.0/doc/md051.md',
           ruleNames: [
@@ -24331,7 +24331,7 @@ Generated by [AVA](https://avajs.dev).
             21,
           ],
           fixInfo: null,
-          lineNumber: 267,
+          lineNumber: 277,
           ruleDescription: 'Link fragments should be valid',
           ruleInformation: 'https://github.com/DavidAnson/markdownlint/blob/v0.0.0/doc/md051.md',
           ruleNames: [
@@ -24406,6 +24406,10 @@ Generated by [AVA](https://avajs.dev).
       ␊
       [Valid](#valid-heading-has-)␊
       ␊
+      [Valid](#valid_heading-escaped_underscores)␊
+      ␊
+      [Valid](#valid\\_heading\\-escaped\\_underscores)␊
+      ␊
       [Valid](#namedlink)␊
       ␊
       [Valid](#idlink)␊
@@ -24420,6 +24424,8 @@ Generated by [AVA](https://avajs.dev).
       ␊
       [Valid][goodref]␊
       ␊
+      [Valid][escapedref]␊
+      ␊
       ### Valid H3 Heading␊
       ␊
       Text␊
@@ -24501,6 +24507,8 @@ Generated by [AVA](https://avajs.dev).
       ␊
       ### Valid Heading Has ![an Image](https://example.com)␊
       ␊
+      ### Valid_Heading Escaped_Underscores␊
+      ␊
       <a name="namedlink"></a>␊
       ␊
       <a id = idlink></a>␊
@@ -24519,6 +24527,8 @@ Generated by [AVA](https://avajs.dev).
       ␊
       [goodref]: #namedlink␊
       ␊
+      [escapedref]: #valid\\_heading\\-escaped\\_underscores␊
+      ␊
       ## Invalid Fragments␊
       ␊
       [Invalid](#valid-heading-is-an-image) {MD051}␊