fix filename length limit error

sdk/evaluation/azure-ai-evaluation/azure/ai/evaluation/_legacy/prompty/_utils.py

@@ -420,17 +420,27 @@ def local_to_base64(local_file: str, mime_type: Optional[str]) -> str:
     else:
         # assume it's a file path
         local_file = (match.group("link") or "").strip()
-        path = Path(local_file)
-        if not path.is_absolute():
-            path = working_dir / local_file
-        if not path.exists():
-            # The link could not be resolved to an existing local file. This can happen when markdown
-            # image syntax (e.g. ![alt](figures/1.1)) originates from Document Intelligence or similar
-            # services where the paths are relative references that are not actual files on disk.
-            # Treat the original markdown as plain text instead of crashing.
+        try:
+            path = Path(local_file)
+            if not path.is_absolute():
+                path = working_dir / local_file
+            if not path.exists():
+                # The link could not be resolved to an existing local file. This can happen when markdown
+                # image syntax (e.g. ![alt](figures/1.1)) originates from Document Intelligence or similar
+                # services where the paths are relative references that are not actual files on disk.
+                # Treat the original markdown as plain text instead of crashing.
+                logger.debug(
+                    "Image reference '%s' could not be resolved to an existing file. Treating as plain text.",
+                    image,
+                )
+                return {"type": "text", "text": image}
+        except (OSError, ValueError) as e:
+            # Path operations can fail when the filename exceeds OS limits (e.g., Linux 255-char name limit)
+            # or contains invalid characters. Treat as plain text rather than crashing.
             logger.debug(
-                "Image reference '%s' could not be resolved to an existing file. Treating as plain text.",
+                "Image reference '%s' could not be resolved to a valid path (%s). Treating as plain text.",
                 image,
+                e,
             )
             return {"type": "text", "text": image}
         inlined_uri = local_to_base64(local_file, mime_type)

sdk/evaluation/azure-ai-evaluation/tests/unittests/test_inline_image_fallback.py

@@ -69,6 +69,19 @@ def test_unparseable_markdown_image_returns_text(self, tmp_path):
         assert result["type"] == "text"
         assert result["text"] == '![alt](url "title")'
 
+    def test_filename_exceeds_os_limit_returns_text(self, tmp_path):
+        """A filename exceeding the OS name limit (255 chars on Linux) should return text, not raise."""
+        long_name = "a" * 300 + ".png"
+        result = _inline_image(f"![alt]({long_name})", tmp_path, "auto")
+        assert result["type"] == "text"
+        assert result["text"] == f"![alt]({long_name})"
+
+    def test_path_with_null_byte_returns_text(self, tmp_path):
+        """A path containing a null byte should return text, not raise."""
+        result = _inline_image("![alt](invalid\x00path.png)", tmp_path, "auto")
+        assert result["type"] == "text"
+        assert result["text"] == "![alt](invalid\x00path.png)"
+
     def test_real_local_image_file(self, tmp_path):
         """A real local image file should still be base64-encoded as before."""
         # Create a minimal valid PNG file (1x1 pixel)
@@ -125,6 +138,14 @@ def test_text_with_empty_alt_text_image(self, tmp_path):
         for item in result:
             assert item["type"] == "text"
 
+    def test_text_with_filename_exceeding_os_limit(self, tmp_path):
+        """A filename exceeding OS limits in mixed content should become text, not crash."""
+        long_name = "b" * 300 + ".png"
+        result = _to_content_str_or_list(f"Text ![img]({long_name}) end", tmp_path, "auto")
+        assert isinstance(result, list)
+        for item in result:
+            assert item["type"] == "text"
+
     def test_real_local_image_in_mixed_content(self, tmp_path):
         """Real local image file mixed with text should work as before."""
         png_data = base64.b64decode(