fix(multimodal): check image path is file before open (#18043)

llama-index-core/llama_index/core/multi_modal_llms/generic_utils.py

 import base64
+import os
+
 import filetype
 import logging
 from typing import List, Optional, Sequence
@@ -57,13 +59,14 @@ def image_documents_to_base64(
     for image_document in image_documents:
         if image_document.image:  # This field is already base64-encoded
             image_encodings.append(image_document.image)
-        elif (
+        elif image_document.image_path and os.path.isfile(
             image_document.image_path
         ):  # This field is a path to the image, which is then encoded.
             image_encodings.append(encode_image(image_document.image_path))
         elif (
             "file_path" in image_document.metadata
             and image_document.metadata["file_path"] != ""
+            and os.path.isfile(image_document.metadata["file_path"])
         ):  # Alternative path to the image, which is then encoded.
             image_encodings.append(encode_image(image_document.metadata["file_path"]))
         elif image_document.image_url:  # Image can also be pulled from the URL.

llama-index-core/tests/multi_modal_llms/test_generic_utils.py

@@ -61,8 +61,9 @@ def test_image_documents_to_base64_multiple_sources():
     ]
     with patch("requests.get") as mock_get:
         mock_get.return_value.content = EXP_BINARY
-        with patch("builtins.open", mock_open(read_data=EXP_BINARY)):
-            result = image_documents_to_base64(documents)
+        with patch("os.path.isfile", return_value=True):
+            with patch("builtins.open", mock_open(read_data=EXP_BINARY)):
+                result = image_documents_to_base64(documents)
 
     assert len(result) == 4
     assert all(encoding == EXP_BASE64 for encoding in result)
@@ -144,8 +145,10 @@ def test_set_base64_and_mimetype_for_image_docs():
 
     with patch("requests.get") as mock_get:
         mock_get.return_value.content = EXP_BINARY
-        with patch("builtins.open", mock_open(read_data=EXP_BINARY)):
-            results = set_base64_and_mimetype_for_image_docs(image_docs)
+        # patch os.path.isfile
+        with patch("os.path.isfile", return_value=True):
+            with patch("builtins.open", mock_open(read_data=EXP_BINARY)):
+                results = set_base64_and_mimetype_for_image_docs(image_docs)
 
     assert len(results) == 2
     assert results[0].image == EXP_BASE64