Update MD051/link-fragments to add the ignored_pattern configuration parameter (fixes #547).

doc-build/md051.md

@@ -74,6 +74,12 @@ And this link to content starting within line 19 running into line 21:
 [Link](#L19C5-L21C11)
 ```
 
+Some Markdown generators dynamically create and insert headings when building
+documents, for example by combining a fixed prefix like `figure-` and an
+incrementing numeric counter. To ignore such generated fragments, set the
+`ignored_pattern` [regular expression][RegEx] parameter to a pattern that
+matches (e.g., `^figure-`).
+
 Rationale: [GitHub section links][github-section-links] are created
 automatically for every heading when Markdown content is displayed on GitHub.
 This makes it easy to link directly to different sections within a document.
@@ -89,3 +95,4 @@ append an incrementing integer as needed for uniqueness.
 [github-heading-algorithm]: https://github.com/gjtorikian/html-pipeline/blob/f13a1534cb650ba17af400d1acd3a22c28004c09/lib/html/pipeline/toc_filter.rb
 [github-linking-to-content]: https://docs.github.com/en/get-started/writing-on-github/working-with-advanced-formatting/creating-a-permanent-link-to-a-code-snippet#linking-to-markdown#linking-to-markdown
 [html-top-fragment]: https://html.spec.whatwg.org/multipage/browsing-the-web.html#scrolling-to-a-fragment
+[RegEx]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_expressions

doc/Rules.md

@@ -2156,6 +2156,8 @@ Aliases: `link-fragments`
 Parameters:
 
 - `ignore_case`: Ignore case of fragments (`boolean`, default `false`)
+- `ignored_pattern`: Pattern for ignoring additional fragments (`string`,
+  default ``)
 
 Fixable: Some violations can be fixed by tooling
 
@@ -2235,6 +2237,12 @@ And this link to content starting within line 19 running into line 21:
 [Link](#L19C5-L21C11)
 ```
 
+Some Markdown generators dynamically create and insert headings when building
+documents, for example by combining a fixed prefix like `figure-` and an
+incrementing numeric counter. To ignore such generated fragments, set the
+`ignored_pattern` [regular expression][RegEx] parameter to a pattern that
+matches (e.g., `^figure-`).
+
 Rationale: [GitHub section links][github-section-links] are created
 automatically for every heading when Markdown content is displayed on GitHub.
 This makes it easy to link directly to different sections within a document.
@@ -2250,6 +2258,7 @@ append an incrementing integer as needed for uniqueness.
 [github-heading-algorithm]: https://github.com/gjtorikian/html-pipeline/blob/f13a1534cb650ba17af400d1acd3a22c28004c09/lib/html/pipeline/toc_filter.rb
 [github-linking-to-content]: https://docs.github.com/en/get-started/writing-on-github/working-with-advanced-formatting/creating-a-permanent-link-to-a-code-snippet#linking-to-markdown#linking-to-markdown
 [html-top-fragment]: https://html.spec.whatwg.org/multipage/browsing-the-web.html#scrolling-to-a-fragment
+[RegEx]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_expressions
 
 <a name="md052"></a>
 

doc/md051.md

@@ -7,6 +7,8 @@ Aliases: `link-fragments`
 Parameters:
 
 - `ignore_case`: Ignore case of fragments (`boolean`, default `false`)
+- `ignored_pattern`: Pattern for ignoring additional fragments (`string`,
+  default ``)
 
 Fixable: Some violations can be fixed by tooling
 
@@ -86,6 +88,12 @@ And this link to content starting within line 19 running into line 21:
 [Link](#L19C5-L21C11)
 ```
 
+Some Markdown generators dynamically create and insert headings when building
+documents, for example by combining a fixed prefix like `figure-` and an
+incrementing numeric counter. To ignore such generated fragments, set the
+`ignored_pattern` [regular expression][RegEx] parameter to a pattern that
+matches (e.g., `^figure-`).
+
 Rationale: [GitHub section links][github-section-links] are created
 automatically for every heading when Markdown content is displayed on GitHub.
 This makes it easy to link directly to different sections within a document.
@@ -101,3 +109,4 @@ append an incrementing integer as needed for uniqueness.
 [github-heading-algorithm]: https://github.com/gjtorikian/html-pipeline/blob/f13a1534cb650ba17af400d1acd3a22c28004c09/lib/html/pipeline/toc_filter.rb
 [github-linking-to-content]: https://docs.github.com/en/get-started/writing-on-github/working-with-advanced-formatting/creating-a-permanent-link-to-a-code-snippet#linking-to-markdown#linking-to-markdown
 [html-top-fragment]: https://html.spec.whatwg.org/multipage/browsing-the-web.html#scrolling-to-a-fragment
+[RegEx]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_expressions

lib/configuration-strict.d.ts

@@ -970,6 +970,10 @@ export interface ConfigurationStrict {
          * Ignore case of fragments
          */
         ignore_case?: boolean;
+        /**
+         * Pattern for ignoring additional fragments
+         */
+        ignored_pattern?: string;
       };
   /**
    * MD051/link-fragments : Link fragments should be valid : https://github.com/DavidAnson/markdownlint/blob/v0.37.4/doc/md051.md
@@ -981,6 +985,10 @@ export interface ConfigurationStrict {
          * Ignore case of fragments
          */
         ignore_case?: boolean;
+        /**
+         * Pattern for ignoring additional fragments
+         */
+        ignored_pattern?: string;
       };
   /**
    * MD052/reference-links-images : Reference links and images should use a label that is defined : https://github.com/DavidAnson/markdownlint/blob/v0.37.4/doc/md052.md

lib/md051.mjs

@@ -66,6 +66,8 @@ export default {
   "parser": "micromark",
   "function": function MD051(params, onError) {
     const ignoreCase = params.config.ignore_case || false;
+    const ignoredPattern = params.config.ignored_pattern || "";
+    const ignoredPatternRe = new RegExp(ignoredPattern || "^$");
     /** @type {Map<string, number>} */
     const fragments = new Map([ [ "#top", 0 ] ]);
 
@@ -114,12 +116,14 @@ export default {
         for (const definition of definitions) {
           const { endColumn, startColumn } = definition;
           const text = unescapeStringTokenText(definition);
-          const encodedText = `#${encodeURIComponent(text.slice(1))}`;
+          const textSliceOne = text.slice(1);
+          const encodedText = `#${encodeURIComponent(textSliceOne)}`;
           if (
             (text.length > 1) &&
             text.startsWith("#") &&
             !fragments.has(encodedText) &&
-            !lineFragmentRe.test(encodedText)
+            !lineFragmentRe.test(encodedText) &&
+            !ignoredPatternRe.test(textSliceOne)
           ) {
             let context = undefined;
             let range = undefined;

schema/.markdownlint.jsonc

@@ -268,7 +268,9 @@
   // MD051/link-fragments : Link fragments should be valid : https://github.com/DavidAnson/markdownlint/blob/v0.37.4/doc/md051.md
   "MD051": {
     // Ignore case of fragments
-    "ignore_case": false
+    "ignore_case": false,
+    // Pattern for ignoring additional fragments
+    "ignored_pattern": ""
   },
 
   // MD052/reference-links-images : Reference links and images should use a label that is defined : https://github.com/DavidAnson/markdownlint/blob/v0.37.4/doc/md052.md

schema/.markdownlint.yaml

@@ -242,6 +242,8 @@ MD050:
 MD051:
   # Ignore case of fragments
   ignore_case: false
+  # Pattern for ignoring additional fragments
+  ignored_pattern: ""
 
 # MD052/reference-links-images : Reference links and images should use a label that is defined : https://github.com/DavidAnson/markdownlint/blob/v0.37.4/doc/md052.md
 MD052:

schema/build-config-schema.mjs

@@ -483,6 +483,11 @@ for (const rule of rules) {
           "description": "Ignore case of fragments",
           "type": "boolean",
           "default": false
+        },
+        "ignored_pattern": {
+          "description": "Pattern for ignoring additional fragments",
+          "type": "string",
+          "default": ""
         }
       };
       break;

schema/markdownlint-config-schema-strict.json

@@ -1511,6 +1511,11 @@
           "description": "Ignore case of fragments",
           "type": "boolean",
           "default": false
+        },
+        "ignored_pattern": {
+          "description": "Pattern for ignoring additional fragments",
+          "type": "string",
+          "default": ""
         }
       },
       "additionalProperties": false
@@ -1527,6 +1532,11 @@
           "description": "Ignore case of fragments",
           "type": "boolean",
           "default": false
+        },
+        "ignored_pattern": {
+          "description": "Pattern for ignoring additional fragments",
+          "type": "string",
+          "default": ""
         }
       },
       "additionalProperties": false

schema/markdownlint-config-schema.json

@@ -1511,6 +1511,11 @@
           "description": "Ignore case of fragments",
           "type": "boolean",
           "default": false
+        },
+        "ignored_pattern": {
+          "description": "Pattern for ignoring additional fragments",
+          "type": "string",
+          "default": ""
         }
       },
       "additionalProperties": false
@@ -1527,6 +1532,11 @@
           "description": "Ignore case of fragments",
           "type": "boolean",
           "default": false
+        },
+        "ignored_pattern": {
+          "description": "Pattern for ignoring additional fragments",
+          "type": "string",
+          "default": ""
         }
       },
       "additionalProperties": false

test/link-fragments-ignored-pattern-default.md

@@ -0,0 +1,9 @@
+# Link Fragments Ignored Pattern Default
+
+## Heading
+
+[Present](#heading)
+
+[Ignored](#ignored) {MD051}
+
+[Missing](#missing) {MD051}

test/link-fragments-ignored-pattern-empty.md

@@ -0,0 +1,15 @@
+# Link Fragments Ignored Pattern Empty
+
+## Heading
+
+[Present](#heading)
+
+[Ignored](#ignored) {MD051}
+
+[Missing](#missing) {MD051}
+
+<!-- markdownlint-configure-file {
+  "link-fragments": {
+    "ignored_pattern": ""
+  }
+} -->

test/link-fragments-ignored-pattern-multiple.md

@@ -0,0 +1,15 @@
+# Link Fragments Ignored Pattern Multiple
+
+## Heading
+
+[Present](#heading)
+
+[Ignored](#ignored)
+
+[Missing](#missing)
+
+<!-- markdownlint-configure-file {
+  "link-fragments": {
+    "ignored_pattern": "^igno|^missing$"
+  }
+} -->

test/link-fragments-ignored-pattern-present.md

@@ -0,0 +1,15 @@
+# Link Fragments Ignored Pattern Present
+
+## Heading
+
+[Present](#heading)
+
+[Ignored](#ignored)
+
+[Missing](#missing) {MD051}
+
+<!-- markdownlint-configure-file {
+  "link-fragments": {
+    "ignored_pattern": "^igno"
+  }
+} -->

test/markdownlint-test.mjs

@@ -907,7 +907,7 @@ test("readme", async(t) => {
 });
 
 test("validateJsonUsingConfigSchemaStrict", async(t) => {
-  t.plan(196);
+  t.plan(199);
   // @ts-ignore
   const ajv = new Ajv(ajvOptions);
   const validateSchemaStrict = ajv.compile(configSchemaStrict);

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

@@ -25399,6 +25399,179 @@ Generated by [AVA](https://avajs.dev).
       `,
     }
 
+## link-fragments-ignored-pattern-default.md
+
+> Snapshot 1
+
+    {
+      errors: [
+        {
+          errorContext: '[Ignored](#ignored)',
+          errorDetail: null,
+          errorRange: [
+            1,
+            19,
+          ],
+          fixInfo: null,
+          lineNumber: 7,
+          ruleDescription: 'Link fragments should be valid',
+          ruleInformation: 'https://github.com/DavidAnson/markdownlint/blob/v0.0.0/doc/md051.md',
+          ruleNames: [
+            'MD051',
+            'link-fragments',
+          ],
+        },
+        {
+          errorContext: '[Missing](#missing)',
+          errorDetail: null,
+          errorRange: [
+            1,
+            19,
+          ],
+          fixInfo: null,
+          lineNumber: 9,
+          ruleDescription: 'Link fragments should be valid',
+          ruleInformation: 'https://github.com/DavidAnson/markdownlint/blob/v0.0.0/doc/md051.md',
+          ruleNames: [
+            'MD051',
+            'link-fragments',
+          ],
+        },
+      ],
+      fixed: `# Link Fragments Ignored Pattern Default␊
+      ␊
+      ## Heading␊
+      ␊
+      [Present](#heading)␊
+      ␊
+      [Ignored](#ignored) {MD051}␊
+      ␊
+      [Missing](#missing) {MD051}␊
+      `,
+    }
+
+## link-fragments-ignored-pattern-empty.md
+
+> Snapshot 1
+
+    {
+      errors: [
+        {
+          errorContext: '[Ignored](#ignored)',
+          errorDetail: null,
+          errorRange: [
+            1,
+            19,
+          ],
+          fixInfo: null,
+          lineNumber: 7,
+          ruleDescription: 'Link fragments should be valid',
+          ruleInformation: 'https://github.com/DavidAnson/markdownlint/blob/v0.0.0/doc/md051.md',
+          ruleNames: [
+            'MD051',
+            'link-fragments',
+          ],
+        },
+        {
+          errorContext: '[Missing](#missing)',
+          errorDetail: null,
+          errorRange: [
+            1,
+            19,
+          ],
+          fixInfo: null,
+          lineNumber: 9,
+          ruleDescription: 'Link fragments should be valid',
+          ruleInformation: 'https://github.com/DavidAnson/markdownlint/blob/v0.0.0/doc/md051.md',
+          ruleNames: [
+            'MD051',
+            'link-fragments',
+          ],
+        },
+      ],
+      fixed: `# Link Fragments Ignored Pattern Empty␊
+      ␊
+      ## Heading␊
+      ␊
+      [Present](#heading)␊
+      ␊
+      [Ignored](#ignored) {MD051}␊
+      ␊
+      [Missing](#missing) {MD051}␊
+      ␊
+      <!-- markdownlint-configure-file {␊
+        "link-fragments": {␊
+          "ignored_pattern": ""␊
+        }␊
+      } -->␊
+      `,
+    }
+
+## link-fragments-ignored-pattern-multiple.md
+
+> Snapshot 1
+
+    {
+      errors: [],
+      fixed: `# Link Fragments Ignored Pattern Multiple␊
+      ␊
+      ## Heading␊
+      ␊
+      [Present](#heading)␊
+      ␊
+      [Ignored](#ignored)␊
+      ␊
+      [Missing](#missing)␊
+      ␊
+      <!-- markdownlint-configure-file {␊
+        "link-fragments": {␊
+          "ignored_pattern": "^igno|^missing$"␊
+        }␊
+      } -->␊
+      `,
+    }
+
+## link-fragments-ignored-pattern-present.md
+
+> Snapshot 1
+
+    {
+      errors: [
+        {
+          errorContext: '[Missing](#missing)',
+          errorDetail: null,
+          errorRange: [
+            1,
+            19,
+          ],
+          fixInfo: null,
+          lineNumber: 9,
+          ruleDescription: 'Link fragments should be valid',
+          ruleInformation: 'https://github.com/DavidAnson/markdownlint/blob/v0.0.0/doc/md051.md',
+          ruleNames: [
+            'MD051',
+            'link-fragments',
+          ],
+        },
+      ],
+      fixed: `# Link Fragments Ignored Pattern Present␊
+      ␊
+      ## Heading␊
+      ␊
+      [Present](#heading)␊
+      ␊
+      [Ignored](#ignored)␊
+      ␊
+      [Missing](#missing) {MD051}␊
+      ␊
+      <!-- markdownlint-configure-file {␊
+        "link-fragments": {␊
+          "ignored_pattern": "^igno"␊
+        }␊
+      } -->␊
+      `,
+    }
+
 ## link-fragments.md
 
 > Snapshot 1