From bbc99b7534ab3ed3daec19e3533f993e61f72d3a Mon Sep 17 00:00:00 2001
From: AndrewAvery7 <AndrewAvery7@users.noreply.github.com>
Date: Wed, 5 Aug 2026 21:26:44 -0500
Subject: [PATCH] fix: remove extra closing brace from caron and ring-above
 accents

`CHR["\u030c"]` and `CHR["\u030a"]` each carried a fourth `}`, so the
templates read `\check{{{0}}}}` and `\ocirc{{{0}}}}`. Every other accent
in the table is `\name{{{0}}}`. `oMath2Latex.do_acc` applies these with
`latex_s.format(c_dict["e"])`, and an unbalanced template raises
`ValueError: Single '}' encountered in format string`.

The damage is not limited to the accented equation. `pre_process_docx`
runs `_pre_process_math` over the whole of `word/document.xml` inside a
blanket `except Exception` and, on error, writes the *original*
unprocessed XML back. Mammoth does not render OMML, so a single caron or
ring-above accent silently removes **every** equation in the document,
with no error and a zero exit code.

Both are standard entries in Word's Equation > Accent gallery
(U+030C COMBINING CARON, U+030A COMBINING RING ABOVE).

Measured on the repo's own `equations.docx` fixture: 2 equations
recovered normally, 0 after appending one caron-accented equation, 3
with this fix applied.

Adds `test_docx_math_accents.py`: a table-wide guard asserting every
`{0}` template survives `.format()`, plus direct coverage of the two
affected accents and an unaffected control.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
---
 .../converter_utils/docx/math/latex_dict.py   |  4 +-
 .../tests/test_docx_math_accents.py           | 80 +++++++++++++++++++
 2 files changed, 82 insertions(+), 2 deletions(-)
 create mode 100644 packages/markitdown/tests/test_docx_math_accents.py

diff --git a/packages/markitdown/src/markitdown/converter_utils/docx/math/latex_dict.py b/packages/markitdown/src/markitdown/converter_utils/docx/math/latex_dict.py
index 4c196f50a5..6a76cfab0c 100644
--- a/packages/markitdown/src/markitdown/converter_utils/docx/math/latex_dict.py
+++ b/packages/markitdown/src/markitdown/converter_utils/docx/math/latex_dict.py
@@ -26,8 +26,8 @@
     "\u0307": "\\dot{{{0}}}",
     "\u0308": "\\ddot{{{0}}}",
     "\u0309": "\\ovhook{{{0}}}",
-    "\u030a": "\\ocirc{{{0}}}}",
-    "\u030c": "\\check{{{0}}}}",
+    "\u030a": "\\ocirc{{{0}}}",
+    "\u030c": "\\check{{{0}}}",
     "\u0310": "\\candra{{{0}}}",
     "\u0312": "\\oturnedcomma{{{0}}}",
     "\u0315": "\\ocommatopright{{{0}}}",
diff --git a/packages/markitdown/tests/test_docx_math_accents.py b/packages/markitdown/tests/test_docx_math_accents.py
new file mode 100644
index 0000000000..821d057bc5
--- /dev/null
+++ b/packages/markitdown/tests/test_docx_math_accents.py
@@ -0,0 +1,80 @@
+#!/usr/bin/env python3 -m pytest
+"""Tests for DOCX math accent templates.
+
+Every accent in ``latex_dict.CHR`` is a ``str.format`` template applied by
+``oMath2Latex.do_acc`` as ``latex_s.format(c_dict["e"])``. A template whose
+braces are unbalanced raises ``ValueError`` at that call.
+
+That failure is not local to the equation. ``pre_process_docx`` runs
+``_pre_process_math`` over the whole of ``word/document.xml`` inside a blanket
+``except Exception`` and, on error, writes the *original* unprocessed XML back.
+Mammoth does not render OMML, so a single unformattable accent silently removes
+every equation in the document -- with no error and a zero exit code.
+
+``test_accent_templates_are_formattable`` guards the whole table against that
+class of typo; ``test_caron_and_ring_accents`` covers the two entries that
+carried an extra closing brace.
+"""
+
+from markitdown.converter_utils.docx.math.latex_dict import (
+    CHR,
+    CHR_BO,
+    CHR_DEFAULT,
+    POS,
+    POS_DEFAULT,
+)
+from markitdown.converter_utils.docx.math.omml import load_string
+
+# Accent characters, as Word writes them into <m:chr m:val="...">.
+CARON = "\u030c"  # COMBINING CARON        -> \check
+RING_ABOVE = "\u030a"  # COMBINING RING ABOVE   -> \ocirc
+CIRCUMFLEX = "\u0302"  # COMBINING CIRCUMFLEX   -> \hat
+
+_OMML_DOC = (
+    "<w:document "
+    'xmlns:w="http://schemas.openxmlformats.org/wordprocessingml/2006/main" '
+    'xmlns:m="http://schemas.openxmlformats.org/officeDocument/2006/math">'
+    "<m:oMath><m:acc>"
+    '<m:accPr><m:chr m:val="{chr}"/></m:accPr>'
+    "<m:e><m:r><m:t>x</m:t></m:r></m:e>"
+    "</m:acc></m:oMath></w:document>"
+)
+
+
+def _latex_for_accent(accent_char: str) -> str:
+    """Convert a single accented variable to LaTeX, as pre_process_docx would."""
+    return next(load_string(_OMML_DOC.format(chr=accent_char))).latex
+
+
+def test_accent_templates_are_formattable() -> None:
+    """Every {0} template must survive .format(); do_acc calls it unguarded."""
+    unformattable = []
+    for name, table in (
+        ("CHR", CHR),
+        ("CHR_BO", CHR_BO),
+        ("CHR_DEFAULT", CHR_DEFAULT),
+        ("POS", POS),
+        ("POS_DEFAULT", POS_DEFAULT),
+    ):
+        for key, template in table.items():
+            if not isinstance(template, str) or "{0}" not in template:
+                continue
+            try:
+                template.format("x")
+            except ValueError as exc:
+                unformattable.append(f"{name}[{key!r}] = {template!r}: {exc}")
+
+    assert not unformattable, "unformattable accent templates: " + "; ".join(
+        unformattable
+    )
+
+
+def test_caron_and_ring_accents() -> None:
+    """U+030C and U+030A each carried an extra '}' and raised ValueError."""
+    assert _latex_for_accent(CARON) == "\\check{x}"
+    assert _latex_for_accent(RING_ABOVE) == "\\ocirc{x}"
+
+
+def test_unmodified_accent_still_converts() -> None:
+    """Control: a neighbouring accent that was never broken."""
+    assert _latex_for_accent(CIRCUMFLEX) == "\\hat{x}"