🐛 FIX: dollarmath same-line close absorbs trailing list content

CHANGELOG.md

@@ -1,5 +1,19 @@
 # Change Log
 
+## Unreleased
+
+- 🐛 FIX: `dollarmath` block rule no longer absorbs following content when a same-line-closed `$$...$$` has non-label trailing text (#147)
+
+  A same-line close followed by trailing content that wasn't a label suffix (e.g. `` $$b$$ trailing ``) wasn't recognized as closed, so the rule fell through to its multi-line scan and silently swallowed every following line, including subsequent list items, up to the next `$$` anywhere later in the document:
+
+  ```markdown
+  1. $$a$$
+  1. $$b$$ trailing
+     1. $$c$$
+  ```
+
+  This ambiguous case (closing marker present, but not at end of line and not a label) is now rejected outright, letting the line fall through to normal inline parsing instead.
+
 ## 0.7.0 - 2026-07-19
 
 - ✨ NEW: Add section reference plugin (`section_ref`) (#144)

mdit_py_plugins/dollarmath/index.py

@@ -322,13 +322,21 @@ def _math_block_dollar(
             if lineText.strip().endswith("$$"):
                 haveEndMarker = True
                 end = end - 2 - (len(lineText) - len(lineText.strip()))
-            elif allow_labels:
-                # reverse the line and match
-                eqnoMatch = DOLLAR_EQNO_REV.match(lineText[::-1])
-                if eqnoMatch:
-                    haveEndMarker = True
-                    label = eqnoMatch.group(1)[::-1]
-                    end = end - eqnoMatch.end()
+            else:
+                # a closing marker present but not at end of line and not a label
+                # suffix is ambiguous, so don't greedily scan subsequent lines for it
+                trailing_close = "$$" in lineText[2:]
+                if allow_labels:
+                    # reverse the line and match
+                    eqnoMatch = DOLLAR_EQNO_REV.match(lineText[::-1])
+                    if eqnoMatch:
+                        haveEndMarker = True
+                        label = eqnoMatch.group(1)[::-1]
+                        end = end - eqnoMatch.end()
+                    elif trailing_close:
+                        return False
+                elif trailing_close:
+                    return False
 
         # search for end of block on subsequent line
         if not haveEndMarker:

tests/fixtures/dollar_math.md

@@ -580,3 +580,38 @@ Indented by 4 spaces, DISABLE-CODEBLOCKS
 a
 </div>
 .
+
+same-line-closed block with trailing text is not absorbed into
+a later math block on a following line. (valid=True)
+.
+$$a$$ trailing
+$$c$$
+.
+<p><div class="math inline">a</div> trailing
+<div class="math inline">c</div></p>
+.
+
+same-line-closed block with trailing text inside a list is not
+absorbed into a later list item. (valid=True)
+.
+1. $$a$$
+1. $$b$$ trailing
+   1. $$c$$
+.
+<ol>
+<li>
+<div class="math block">
+a
+</div>
+</li>
+<li><div class="math inline">b</div> trailing
+<ol>
+<li>
+<div class="math block">
+c
+</div>
+</li>
+</ol>
+</li>
+</ol>
+.

tests/test_dollarmath.py

@@ -64,6 +64,21 @@ def test_block_func():
     }
 
 
+@pytest.mark.parametrize("allow_labels", [True, False])
+def test_block_func_ambiguous_trailing_content(allow_labels):
+    """A same-line close followed by non-label trailing content is
+    ambiguous, so the block rule should not match and greedily scan
+    subsequent lines for the next ``$$``.
+    """
+    block_func = main.math_block_dollar(allow_labels=allow_labels)
+    md = MarkdownIt()
+    src = "$$b$$ trailing\n$$c$$\n"
+    tokens = []
+    state = StateBlock(src, md, {}, tokens)
+    assert block_func(state, 0, 2, False) is False
+    assert tokens == []
+
+
 def test_plugin_parse(data_regression):
     md = MarkdownIt().use(dollarmath_plugin)
     tokens = md.parse(