fix: include both endpoint errors when chat.completions fallback also fails

When the responses endpoint fails and the chat.completions fallback also
fails (raises or returns empty), the original responses error was captured
in fallback_reason but never surfaced. Wrap the fallback call in its own
try/except and re-raise a RuntimeError that chains both errors with
context, so users see why both endpoints failed.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

image_to_text_node.py

@@ -164,21 +164,27 @@ class LMStudioImageToText(io.ComfyNode):
             first_image = image[0] if is_batch else image
             image_data_url = comfy_image_to_base64_png_url(first_image)
 
-            completion = client.chat.completions.create(
-                model=connection.model,
-                messages=build_chat_messages_with_image(
-                    system_prompt=system_prompt,
-                    user_prompt=user_prompt,
-                    image_data_url=image_data_url,
-                ),
-                seed=resolved_seed,
-                temperature=connection.temperature,
-                max_tokens=connection.max_tokens,
-                n=1,
-            )
-            text = extract_chat_completion_text(completion).strip()
-            if not text:
-                raise ValueError("chat.completions fallback returned no text output")
+            try:
+                completion = client.chat.completions.create(
+                    model=connection.model,
+                    messages=build_chat_messages_with_image(
+                        system_prompt=system_prompt,
+                        user_prompt=user_prompt,
+                        image_data_url=image_data_url,
+                    ),
+                    seed=resolved_seed,
+                    temperature=connection.temperature,
+                    max_tokens=connection.max_tokens,
+                    n=1,
+                )
+                text = extract_chat_completion_text(completion).strip()
+                if not text:
+                    raise ValueError("chat.completions fallback returned no text output")
+            except Exception as chat_error:
+                raise RuntimeError(
+                    f"Both endpoints failed. responses error: {fallback_reason}. "
+                    f"chat.completions error: {chat_error}"
+                ) from chat_error
 
             if batch_size > 1:
                 fallback_reason += (

tests/test_coverage_gaps.py

@@ -1,312 +0,0 @@
-"""
-Tests targeting the remaining uncovered branches in client.py and image_to_text_node.py.
-
-Coverage gaps addressed (as reported by pytest-cov on the main branch):
-  client.py         : lines 117-118, 142, 207, 222->228, 224->223, 226->223, 234->232, 291->293
-  image_to_text_node: lines 112->114, 157, 181, 183->189
-"""
-from __future__ import annotations
-
-from types import SimpleNamespace
-
-import numpy as np
-import pytest
-
-import client
-from helpers.fakes import FakeTensor, make_chat_completion, ns
-from helpers.imports import import_repo_module
-
-
-# ---------------------------------------------------------------------------
-# client.py – coerce_seed: .item() call raises, falls back to plain value
-# ---------------------------------------------------------------------------
-
-class _BadItem:
-    """Numpy-scalar-like object whose .item() always raises."""
-
-    def item(self):
-        raise RuntimeError("item() failed")
-
-
-def test_coerce_seed_item_raises_falls_back_to_unsupported_type() -> None:
-    """
-    When value has .item() but the call raises, coerce_seed catches the exception
-    (lines 117-118) and falls through to the type-check below. Since _BadItem is
-    not int/float/str/bytes, it must then hit the final raise (line 142).
-    """
-    with pytest.raises(ValueError, match="Unsupported seed type"):
-        client.coerce_seed(_BadItem())
-
-
-def test_coerce_seed_unsupported_type_raises() -> None:
-    """
-    A plain object with no recognised numeric/string interface must raise the
-    'Unsupported seed type' error (line 142).
-    """
-    with pytest.raises(ValueError, match="Unsupported seed type"):
-        client.coerce_seed(object())
-
-    with pytest.raises(ValueError, match="Unsupported seed type"):
-        client.coerce_seed({"a": 1})
-
-
-# ---------------------------------------------------------------------------
-# client.py – extract_chat_completion_text: content=[] returns ""
-# ---------------------------------------------------------------------------
-
-def test_extract_chat_completion_text_empty_list_content() -> None:
-    """
-    When the message.content is an empty list the function should return "".
-    This exercises the branch at line 207 where content is a list but parts
-    ends up empty so "\n".join returns "".
-    """
-    completion = make_chat_completion([])
-    assert client.extract_chat_completion_text(completion) == ""
-
-
-def test_extract_chat_completion_text_list_with_no_usable_text() -> None:
-    """
-    List content items where getattr(part, 'text', None) is None and the item
-    is also not a dict – they are silently skipped, exercising the branches
-    at lines 222->228 / 224->223 / 226->223.
-    """
-    content = [
-        ns(other="no-text"),          # has no .text, not a dict – skipped
-        ns(text=None),                # text attr is None – skipped
-        {"other": "ignored"},         # dict without 'text' key – skipped
-        ns(text="kept"),              # text attr is str – included
-    ]
-    completion = make_chat_completion(content)
-    assert client.extract_chat_completion_text(completion) == "kept"
-
-
-def test_extract_chat_completion_text_non_list_non_str_content() -> None:
-    """
-    When message.content is neither a str nor a list (e.g. an int or None),
-    the function should return "" via the final branch at line 207.
-    """
-    assert client.extract_chat_completion_text(make_chat_completion(42)) == ""
-    assert client.extract_chat_completion_text(make_chat_completion(None)) == ""
-
-
-# ---------------------------------------------------------------------------
-# client.py – extract_responses_text: output list with no content at all
-# ---------------------------------------------------------------------------
-
-def test_extract_responses_text_output_list_empty_items() -> None:
-    """
-    output is a list but its items carry neither usable 'content' lists nor
-    a 'text' attribute, so parts stays empty and the function returns "".
-    This exercises the branch at line 234->232.
-    """
-    response = ns(output_text="", output=[ns(content=None), ns()])
-    assert client.extract_responses_text(response) == ""
-
-
-def test_extract_responses_text_output_none() -> None:
-    """output attribute is None – falls through to return "" at the end."""
-    assert client.extract_responses_text(ns(output_text="", output=None)) == ""
-
-
-# ---------------------------------------------------------------------------
-# client.py – build_chat_messages_with_image: no system prompt (line 291->293)
-# ---------------------------------------------------------------------------
-
-def test_build_chat_messages_with_image_no_system_prompt() -> None:
-    """
-    When system_prompt is blank/empty the system message must be omitted so
-    only the user message is present.  This covers branch 291->293.
-    """
-    messages = client.build_chat_messages_with_image(
-        system_prompt="  ",
-        user_prompt="describe it",
-        image_data_url="data:image/png;base64,abc==",
-    )
-    assert len(messages) == 1
-    assert messages[0]["role"] == "user"
-    user_content = messages[0]["content"]
-    assert user_content[0] == {"type": "text", "text": "describe it"}
-    assert user_content[1]["type"] == "image_url"
-
-    # None system_prompt is treated the same way.
-    messages_none = client.build_chat_messages_with_image(
-        system_prompt=None,
-        user_prompt="hello",
-        image_data_url="data:image/png;base64,xyz==",
-    )
-    assert len(messages_none) == 1
-
-
-# ---------------------------------------------------------------------------
-# image_to_text_node.py – _responses_kwargs: empty system_prompt (line 112->114)
-# ---------------------------------------------------------------------------
-
-def _image_module():
-    return import_repo_module("image_to_text_node", force_reload=True)
-
-
-def _connection_payload(*, reasoning_enabled: bool = False, use_tooling_mcp: bool = False):
-    models = import_repo_module("models", force_reload=True)
-    return models.LMStudioConnectionPayload(
-        server_url="http://127.0.0.1:1234",
-        base_url="http://127.0.0.1:1234/v1",
-        api_key="token",
-        model="vision-model",
-        reasoning_enabled=reasoning_enabled,
-        max_tokens=128,
-        temperature=0.3,
-        timeout_seconds=30,
-        use_tooling_mcp=use_tooling_mcp,
-    )
-
-
-def _single_image() -> FakeTensor:
-    return FakeTensor(np.array([[[1.0, 0.0, 0.0]]], dtype=np.float32))
-
-
-def _batch_image() -> FakeTensor:
-    return FakeTensor(
-        np.array(
-            [
-                [[[1.0, 0.0, 0.0]]],
-                [[[0.0, 0.0, 1.0]]],
-            ],
-            dtype=np.float32,
-        )
-    )
-
-
-def test_responses_kwargs_no_system_prompt_omits_instructions() -> None:
-    """
-    When system_prompt is blank the 'instructions' key must NOT appear in
-    the returned kwargs.  This covers the branch at line 112->114.
-    """
-    image_node = _image_module()
-    kwargs = image_node.LMStudioImageToText._responses_kwargs(
-        connection=_connection_payload(),
-        image=_single_image(),
-        system_prompt="",
-        user_prompt="describe",
-        seed=1,
-    )
-    assert "instructions" not in kwargs
-
-    kwargs_whitespace = image_node.LMStudioImageToText._responses_kwargs(
-        connection=_connection_payload(),
-        image=_single_image(),
-        system_prompt="   ",
-        user_prompt="describe",
-        seed=1,
-    )
-    assert "instructions" not in kwargs_whitespace
-
-
-# ---------------------------------------------------------------------------
-# image_to_text_node.py – execute: responses returns empty text (line 157)
-# ---------------------------------------------------------------------------
-
-def test_execute_responses_empty_text_falls_back_to_chat(
-    monkeypatch: pytest.MonkeyPatch,
-) -> None:
-    """
-    When the responses endpoint returns an empty string the node must raise
-    a ValueError internally and fall back to chat.completions.
-    This covers line 157 ('raise ValueError("responses endpoint returned no text output")').
-    """
-    image_node = _image_module()
-
-    completion = SimpleNamespace(
-        choices=[SimpleNamespace(message=SimpleNamespace(content="chat fallback text"))]
-    )
-    fake_client = SimpleNamespace(
-        responses=SimpleNamespace(create=lambda **_: SimpleNamespace(output_text="")),
-        chat=SimpleNamespace(completions=SimpleNamespace(create=lambda **_: completion)),
-    )
-    monkeypatch.setattr(image_node, "resolve_request_seed", lambda _: 5)
-    monkeypatch.setattr(image_node, "create_openai_client", lambda **_: fake_client)
-
-    output = image_node.LMStudioImageToText.execute(
-        connection=_connection_payload(),
-        image=_single_image(),
-        system_prompt="sys",
-        user_prompt="describe",
-        seed=-1,
-    )
-
-    assert output[0] == "chat fallback text"
-    assert "via chat.completions" in output.ui.text
-    assert "responses endpoint returned no text output" in output.ui.text
-
-
-# ---------------------------------------------------------------------------
-# image_to_text_node.py – execute: chat fallback also empty (line 181)
-# ---------------------------------------------------------------------------
-
-def test_execute_both_endpoints_empty_raises(
-    monkeypatch: pytest.MonkeyPatch,
-) -> None:
-    """
-    When both the responses endpoint and the chat.completions fallback return
-    empty text, a ValueError must propagate to the caller.
-    This covers line 181 ('raise ValueError("chat.completions fallback returned no text output")').
-    """
-    image_node = _image_module()
-
-    empty_completion = SimpleNamespace(
-        choices=[SimpleNamespace(message=SimpleNamespace(content=""))]
-    )
-    fake_client = SimpleNamespace(
-        responses=SimpleNamespace(create=lambda **_: SimpleNamespace(output_text="")),
-        chat=SimpleNamespace(completions=SimpleNamespace(create=lambda **_: empty_completion)),
-    )
-    monkeypatch.setattr(image_node, "resolve_request_seed", lambda _: 3)
-    monkeypatch.setattr(image_node, "create_openai_client", lambda **_: fake_client)
-
-    with pytest.raises(ValueError, match="chat.completions fallback returned no text output"):
-        image_node.LMStudioImageToText.execute(
-            connection=_connection_payload(),
-            image=_single_image(),
-            system_prompt="sys",
-            user_prompt="describe",
-            seed=0,
-        )
-
-
-# ---------------------------------------------------------------------------
-# image_to_text_node.py – execute: chat fallback single image, no dropped-frames note (line 183->189)
-# ---------------------------------------------------------------------------
-
-def test_execute_chat_fallback_single_image_no_dropped_frames_note(
-    monkeypatch: pytest.MonkeyPatch,
-) -> None:
-    """
-    When the responses endpoint fails and the image is a *single* frame (not a
-    batch), the fallback status message must NOT mention dropped frames.
-    This covers the branch at line 183->189 where batch_size == 1.
-    """
-    image_node = _image_module()
-
-    def raise_responses(**kwargs):
-        raise RuntimeError("responses unavailable")
-
-    completion = SimpleNamespace(
-        choices=[SimpleNamespace(message=SimpleNamespace(content="single fallback"))]
-    )
-    fake_client = SimpleNamespace(
-        responses=SimpleNamespace(create=raise_responses),
-        chat=SimpleNamespace(completions=SimpleNamespace(create=lambda **_: completion)),
-    )
-    monkeypatch.setattr(image_node, "resolve_request_seed", lambda _: 7)
-    monkeypatch.setattr(image_node, "create_openai_client", lambda **_: fake_client)
-
-    output = image_node.LMStudioImageToText.execute(
-        connection=_connection_payload(),
-        image=_single_image(),
-        system_prompt="sys",
-        user_prompt="describe",
-        seed=0,
-    )
-
-    assert output[0] == "single fallback"
-    assert "via chat.completions" in output.ui.text
-    assert "dropped" not in output.ui.text

tests/test_image_to_text_node.py

@@ -158,3 +158,41 @@ def test_execute_chat_fallback_reports_dropped_frames(
     assert "via chat.completions" in output.ui.text
     assert "responses unavailable" in output.ui.text
     assert "additional frame(s) were dropped" in output.ui.text
+
+
+def test_execute_chains_both_errors_when_chat_completions_also_raises(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    image_node = _image_module()
+
+    def raise_responses(**kwargs):
+        raise RuntimeError("responses boom")
+
+    def raise_chat(**kwargs):
+        raise RuntimeError("chat boom")
+
+    fake_client = SimpleNamespace(
+        responses=SimpleNamespace(create=raise_responses),
+        chat=SimpleNamespace(completions=SimpleNamespace(create=raise_chat)),
+    )
+    monkeypatch.setattr(image_node, "resolve_request_seed", lambda _: 41)
+    monkeypatch.setattr(image_node, "create_openai_client", lambda **_: fake_client)
+    monkeypatch.setattr(
+        image_node, "comfy_image_to_base64_png_url", lambda _img: "data:image/png;base64,xxx"
+    )
+
+    with pytest.raises(RuntimeError) as exc_info:
+        image_node.LMStudioImageToText.execute(
+            connection=_connection_payload(),
+            image=_single_image(),
+            system_prompt="sys",
+            user_prompt="describe",
+            seed=0,
+        )
+
+    message = str(exc_info.value)
+    assert "Both endpoints failed" in message
+    assert "responses boom" in message
+    assert "chat boom" in message
+    assert isinstance(exc_info.value.__cause__, RuntimeError)
+    assert str(exc_info.value.__cause__) == "chat boom"

tests/test_text_gen_node.py

@@ -161,10 +161,50 @@ def test_execute_raises_if_both_endpoints_return_no_text(
     monkeypatch.setattr(text_gen_node, "create_openai_client", lambda **_: fake_client)
     monkeypatch.setattr(text_gen_node, "resolve_request_seed", lambda _: 55)
 
-    with pytest.raises(ValueError, match="chat\\.completions fallback returned no text output"):
+    with pytest.raises(RuntimeError) as exc_info:
         text_gen_node.LMStudioTextGen.execute(
             connection=_connection_payload(),
             system_prompt="sys",
             user_prompt="hello",
             seed=1,
         )
+
+    message = str(exc_info.value)
+    assert "Both endpoints failed" in message
+    assert "responses endpoint returned no text output" in message
+    assert "chat.completions fallback returned no text output" in message
+
+
+def test_execute_chains_both_errors_when_chat_completions_also_raises(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    text_gen_node = _text_module()
+
+    def raise_responses(**kwargs):
+        raise RuntimeError("responses boom")
+
+    def raise_chat(**kwargs):
+        raise RuntimeError("chat boom")
+
+    fake_client = SimpleNamespace(
+        responses=SimpleNamespace(create=raise_responses),
+        chat=SimpleNamespace(completions=SimpleNamespace(create=raise_chat)),
+    )
+
+    monkeypatch.setattr(text_gen_node, "create_openai_client", lambda **_: fake_client)
+    monkeypatch.setattr(text_gen_node, "resolve_request_seed", lambda _: 55)
+
+    with pytest.raises(RuntimeError) as exc_info:
+        text_gen_node.LMStudioTextGen.execute(
+            connection=_connection_payload(),
+            system_prompt="sys",
+            user_prompt="hello",
+            seed=1,
+        )
+
+    message = str(exc_info.value)
+    assert "Both endpoints failed" in message
+    assert "responses boom" in message
+    assert "chat boom" in message
+    assert isinstance(exc_info.value.__cause__, RuntimeError)
+    assert str(exc_info.value.__cause__) == "chat boom"

text_gen_node.py

@@ -136,17 +136,23 @@ class LMStudioTextGen(io.ComfyNode):
             via_endpoint = "chat.completions"
             fallback_reason = str(responses_error)
 
-            completion = client.chat.completions.create(
-                model=connection.model,
-                messages=build_chat_messages(system_prompt, user_prompt),
-                seed=resolved_seed,
-                temperature=connection.temperature,
-                max_tokens=connection.max_tokens,
-                n=1,
-            )
-            text = extract_chat_completion_text(completion).strip()
-            if not text:
-                raise ValueError("chat.completions fallback returned no text output")
+            try:
+                completion = client.chat.completions.create(
+                    model=connection.model,
+                    messages=build_chat_messages(system_prompt, user_prompt),
+                    seed=resolved_seed,
+                    temperature=connection.temperature,
+                    max_tokens=connection.max_tokens,
+                    n=1,
+                )
+                text = extract_chat_completion_text(completion).strip()
+                if not text:
+                    raise ValueError("chat.completions fallback returned no text output")
+            except Exception as chat_error:
+                raise RuntimeError(
+                    f"Both endpoints failed. responses error: {fallback_reason}. "
+                    f"chat.completions error: {chat_error}"
+                ) from chat_error
 
         text = strip_think_content(text)