Update MD036/no-emphasis-as-heading to ignore HTML comments at the beginning or ending of the emphasised heading (fixes #1267).

lib/md036.mjs

@@ -11,6 +11,11 @@ const emphasisTypes = [
   [ "strong", "strongText" ]
 ];
 
+const isParagraphChildMeaningful = (token) => !(
+  (token.type === "htmlText") ||
+  ((token.type === "data") && (token.text.trim().length === 0))
+);
+
 /** @type {import("markdownlint").Rule} */
 export default {
   "names": [ "MD036", "no-emphasis-as-heading" ],
@@ -22,9 +27,14 @@ export default {
     punctuation = String((punctuation === undefined) ? allPunctuation : punctuation);
     const punctuationRe = new RegExp("[" + punctuation + "]$");
     const paragraphTokens =
-      filterByTypesCached([ "paragraph" ])
+      filterByTypesCached([ "paragraph" ], true)
         .filter((token) =>
-          (token.parent?.type === "content") && !token.parent?.parent && (token.children.length === 1)
+          (token.parent?.type === "content") &&
+          (
+            !token.parent?.parent ||
+            ((token.parent?.parent?.type === "htmlFlow") && !token.parent?.parent?.parent)
+          ) &&
+          (token.children.filter(isParagraphChildMeaningful).length === 1)
         );
     for (const emphasisType of emphasisTypes) {
       const textTokens = getDescendantsByType(paragraphTokens, emphasisType);

test/emphasis_instead_of_headings.md

@@ -44,3 +44,15 @@ detected as a heading because it's on multiple lines**
 **This shouldn't be detected as a heading as it ends in full-width punctuation。**
 
 **[This as well since it is a link](https://example.com)**
+
+*Section 4: emphasis as heading {MD036}* <!-- comment -->
+
+Emphasis as heading followed by an HTML comment
+
+<!-- comment --> __Section 5: emphasis as heading {MD036}__
+
+Emphasis as heading following an HTML comment
+
+*Section 6: emphasis <!-- comment --> as non-heading*
+
+Embedded HTML comments are unusual and cause the emphasis to be ignored/allowed

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

@@ -11850,6 +11850,32 @@ Generated by [AVA](https://avajs.dev).
             'no-emphasis-as-heading',
           ],
         },
+        {
+          errorContext: 'Section 4: emphasis as heading...',
+          errorDetail: null,
+          errorRange: null,
+          fixInfo: null,
+          lineNumber: 48,
+          ruleDescription: 'Emphasis used instead of a heading',
+          ruleInformation: 'https://github.com/DavidAnson/markdownlint/blob/v0.0.0/doc/md036.md',
+          ruleNames: [
+            'MD036',
+            'no-emphasis-as-heading',
+          ],
+        },
+        {
+          errorContext: 'Section 5: emphasis as heading...',
+          errorDetail: null,
+          errorRange: null,
+          fixInfo: null,
+          lineNumber: 52,
+          ruleDescription: 'Emphasis used instead of a heading',
+          ruleInformation: 'https://github.com/DavidAnson/markdownlint/blob/v0.0.0/doc/md036.md',
+          ruleNames: [
+            'MD036',
+            'no-emphasis-as-heading',
+          ],
+        },
         {
           errorContext: null,
           errorDetail: 'Expected: asterisk; Actual: underscore',
@@ -11977,6 +12003,18 @@ Generated by [AVA](https://avajs.dev).
       **This shouldn't be detected as a heading as it ends in full-width punctuation。**␊
       ␊
       **[This as well since it is a link](https://example.com)**␊
+      ␊
+      *Section 4: emphasis as heading {MD036}* <!-- comment -->␊
+      ␊
+      Emphasis as heading followed by an HTML comment␊
+      ␊
+      <!-- comment --> __Section 5: emphasis as heading {MD036}__␊
+      ␊
+      Emphasis as heading following an HTML comment␊
+      ␊
+      *Section 6: emphasis <!-- comment --> as non-heading*␊
+      ␊
+      Embedded HTML comments are unusual and cause the emphasis to be ignored/allowed␊
       `,
     }