From 9f1e255d9fbaddb6136de507fa64d9f4fb7c1335 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E6=B5=85=E5=90=9F=E5=8D=8A=E5=A4=8F?= <836205695@qq.com>
Date: Sun, 31 May 2026 09:29:41 +0800
Subject: [PATCH] fix: fallback when CSV charset hint fails

---
 .../src/markitdown/converters/_csv_converter.py    |  8 ++++++--
 packages/markitdown/tests/test_module_misc.py      | 14 ++++++++++++++
 2 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/packages/markitdown/src/markitdown/converters/_csv_converter.py b/packages/markitdown/src/markitdown/converters/_csv_converter.py
index 7e9631e1b..4567bff71 100644
--- a/packages/markitdown/src/markitdown/converters/_csv_converter.py
+++ b/packages/markitdown/src/markitdown/converters/_csv_converter.py
@@ -42,10 +42,14 @@ def convert(
         **kwargs: Any,  # Options to pass to the converter
     ) -> DocumentConverterResult:
         # Read the file content
+        data = file_stream.read()
         if stream_info.charset:
-            content = file_stream.read().decode(stream_info.charset)
+            try:
+                content = data.decode(stream_info.charset)
+            except UnicodeDecodeError:
+                content = str(from_bytes(data).best())
         else:
-            content = str(from_bytes(file_stream.read()).best())
+            content = str(from_bytes(data).best())
 
         # Parse CSV content
         reader = csv.reader(io.StringIO(content))
diff --git a/packages/markitdown/tests/test_module_misc.py b/packages/markitdown/tests/test_module_misc.py
index 4d62e4919..d3b4570ec 100644
--- a/packages/markitdown/tests/test_module_misc.py
+++ b/packages/markitdown/tests/test_module_misc.py
@@ -220,6 +220,20 @@ def test_data_uris() -> None:
     assert data == b"Hello, World!"
 
 
+def test_csv_falls_back_when_charset_hint_fails() -> None:
+    content = ("x" * 4096 + ",café\n").encode("utf-8")
+    result = MarkItDown().convert(
+        io.BytesIO(content),
+        stream_info=StreamInfo(
+            extension=".csv",
+            mimetype="text/csv",
+            charset="ascii",
+        ),
+    )
+
+    assert "café" in result.markdown
+
+
 def test_file_uris() -> None:
     # Test file URI with an empty host
     file_uri = "file:///path/to/file.txt"