🐛 FIX: html_block: blank lines inside containers prematurely terminate non-blank-line-terminator sequences

markdown_it/rules_block/html_block.py

@@ -67,11 +67,22 @@ def html_block(state: StateBlock, startLine: int, endLine: int, silent: bool) ->
 
     nextLine = startLine + 1
 
+    # Block types 6 and 7 (the only ones whose end condition is a blank line)
+    # have `^$` as their closing regexp. For all other types (1-5, e.g.
+    # `<!--` comments), a blank line is regular content and must not terminate
+    # the block - it ends only when its closing sequence is found.
+    endsOnBlankLine = bool(html_seq[1].search(""))
+
     # If we are here - we detected HTML block.
     # Let's roll down till block end.
     if not html_seq[1].search(lineText):
         while nextLine < endLine:
-            if state.sCount[nextLine] < state.blkIndent:
+            # An outdented blank line shouldn't end a block that doesn't end on a
+            # blank line (e.g. a `<!--` comment inside a list item). Such blocks
+            # must continue until their closing sequence regardless of indent.
+            if state.sCount[nextLine] < state.blkIndent and (
+                endsOnBlankLine or not state.isEmpty(nextLine)
+            ):
                 break
 
             pos = state.bMarks[nextLine] + state.tShift[nextLine]

tests/test_port/fixtures/commonmark_extras.md

@@ -828,3 +828,46 @@ A no-break space is not a space, so a code span holding one between single space
 .
 <p><code> </code></p>
 .
+
+Issue #1144. Comment HTML block (type 2) must not end on a blank line inside a list
+.
+1. item
+
+    <!--
+    a
+
+    b
+    -->
+    c
+.
+<ol>
+<li>
+<p>item</p>
+ <!--
+ a
+
+ b
+ -->
+<p>c</p>
+</li>
+</ol>
+.
+
+Issue #1144. Comment HTML block spanning a blank line inside a blockquote
+.
+> <!--
+> a
+>
+> b
+> -->
+> c
+.
+<blockquote>
+<!--
+a
+
+b
+-->
+<p>c</p>
+</blockquote>
+.

tests/test_port/fixtures/issue-fixes.md

@@ -108,3 +108,35 @@ Image alt keeps escapes, entities and code span text together
 .
 <p><img src="/u" alt="a * c&lt;d &amp; e" /></p>
 .
+
+#377 comment HTML block in a list item still ends at the next item after a blank line
+.
+- <!--
+
+- b
+.
+<ul>
+<li>
+<!--
+
+</li>
+<li>
+<p>b</p>
+</li>
+</ul>
+.
+
+#377 comment HTML block in a list item still ends at an outdented non-blank line
+.
+- <!--
+foo
+-->
+.
+<ul>
+<li>
+<!--
+</li>
+</ul>
+<p>foo
+--&gt;</p>
+.