fix: honor empty-string metadata overrides

invokeai/app/api/extract_metadata_from_image.py

@@ -48,7 +48,9 @@ def extract_metadata_from_image(
     stringified_metadata: str | None = None
 
     # Use the metadata override if provided, else attempt to extract it from the image file.
-    metadata_raw = invokeai_metadata_override or pil_image.info.get("invokeai_metadata", None)
+    metadata_raw = (
+        invokeai_metadata_override if invokeai_metadata_override is not None else pil_image.info.get("invokeai_metadata", None)
+    )
 
     # If the metadata is present in the image file, we will attempt to parse it as JSON. When we create images,
     # we always store metadata as a stringified JSON dict. So, we expect it to be a string here.
@@ -66,7 +68,9 @@ def extract_metadata_from_image(
 
     # We expect the workflow, if embedded in the image, to be a JSON-stringified WorkflowWithoutID. We will store it
     # as a string.
-    workflow_raw: str | None = invokeai_workflow_override or pil_image.info.get("invokeai_workflow", None)
+    workflow_raw: str | None = (
+        invokeai_workflow_override if invokeai_workflow_override is not None else pil_image.info.get("invokeai_workflow", None)
+    )
 
     # The fallback value for workflow is None.
     stringified_workflow: str | None = None
@@ -85,7 +89,9 @@ def extract_metadata_from_image(
 
     # We expect the workflow, if embedded in the image, to be a JSON-stringified Graph. We will store it as a
     # string.
-    graph_raw: str | None = invokeai_graph_override or pil_image.info.get("invokeai_graph", None)
+    graph_raw: str | None = (
+        invokeai_graph_override if invokeai_graph_override is not None else pil_image.info.get("invokeai_graph", None)
+    )
 
     # The fallback value for graph is None.
     stringified_graph: str | None = None

tests/app/test_extract_metadata_from_image.py

@@ -204,3 +204,18 @@ def test_with_no_metadata(mock_logger):
     assert result.invokeai_metadata is None
     assert result.invokeai_workflow is None
     assert result.invokeai_graph is None
+
+
+def test_empty_string_overrides_do_not_fall_back_to_image_metadata(mock_logger, valid_metadata, valid_workflow, valid_graph):
+    mock_image = MagicMock(spec=Image.Image)
+    mock_image.info = {
+        "invokeai_metadata": valid_metadata,
+        "invokeai_workflow": valid_workflow,
+        "invokeai_graph": valid_graph,
+    }
+
+    result = extract_metadata_from_image(mock_image, "", "", "", mock_logger)
+
+    assert result.invokeai_metadata is None
+    assert result.invokeai_workflow is None
+    assert result.invokeai_graph is None