🐛 FIX: parse front matter closed by the YAML ... marker

CHANGELOG.md

@@ -1,5 +1,21 @@
 # Change Log
 
+## Unreleased
+
+- 🐛 FIX: front matter closed by `...` is parsed correctly
+
+  The YAML document-end marker was tested against the previous line rather than
+  the current one, because `start`/`maximum` were only moved onto the current
+  line after the test. Two things followed: a block whose last line was `...` was
+  dropped entirely, so the front matter leaked into the document as visible text,
+  and where it did parse, the marker itself was included in the token content.
+
+  ```python
+  MarkdownIt().use(front_matter_plugin).render("---\ntitle: a\n...\n")
+  # before: '<hr />\n<p>title: a\n...</p>\n'
+  # after:  ''
+  ```
+
 ## 0.7.0 - 2026-07-19
 
 - ✨ NEW: Add section reference plugin (`section_ref`) (#144)

mdit_py_plugins/front_matter/index.py

@@ -69,12 +69,17 @@ def _front_matter_rule(
             # unclosed block should be autoclosed by end of document.
             return False
 
-        if state.src[start:maximum] == "...":
-            break
-
         start = state.bMarks[nextLine] + state.tShift[nextLine]
         maximum = state.eMarks[nextLine]
 
+        if state.src[start:maximum] == "...":
+            # The YAML document-end marker closes the block on this line, so it must
+            # be consumed here: checking it before start/maximum are moved onto the
+            # current line tests the previous one, which both missed a `...` that
+            # ends the document and leaked the marker into the extracted content.
+            auto_closed = True
+            break
+
         if start < maximum and state.sCount[nextLine] < state.blkIndent:
             # non-empty line with negative indent should stop the list:
             # - ```

tests/test_front_matter.py

@@ -42,6 +42,30 @@ def test_token():
     ]
 
 
+@pytest.mark.parametrize("closer", ["---", "..."])
+def test_token_content_excludes_the_closer(closer):
+    """The closing marker must not be left inside the extracted content.
+
+    ``...`` is the YAML document-end marker and is exercised by the fixture file,
+    so it has to be consumed like the dashed form rather than kept in the block.
+    """
+    md = MarkdownIt("commonmark").use(front_matter_plugin)
+    tokens = md.parse(f"---\na: 1\n{closer}")
+    assert [token.type for token in tokens] == ["front_matter"]
+    assert tokens[0].content == "a: 1"
+
+
+def test_dots_closer_on_the_last_line():
+    """A block closed by ``...`` on the final line is still front matter.
+
+    ``test_all`` cannot see this: the front_matter token is hidden, so only the
+    rendered output is asserted, and a block that is dropped rather than closed
+    renders as visible text instead of disappearing.
+    """
+    md = MarkdownIt("commonmark").use(front_matter_plugin)
+    assert md.render("---\na: 1\n...\n") == md.render("---\na: 1\n---\n") == ""
+
+
 def test_short_source():
     md = MarkdownIt("commonmark").use(front_matter_plugin)