fix(providers): match google submodule imports and walk full exception chain

Co-Authored-By: Ahmed Allam <ahmed39652003@gmail.com>

strix/interface/main.py

@@ -62,7 +62,7 @@ BEDROCK_EXTRA_HINT = (
     'Bedrock support is optional. Install it with: pipx install "strix-agent[bedrock]"'
 )
 VERTEX_MODEL_MARKER = "vertex"
-VERTEX_MISSING_MODULE_ERROR = "No module named 'google'"
+VERTEX_MISSING_MODULE_ERROR = "No module named 'google"
 VERTEX_EXTRA_HINT = (
     'Vertex AI support is optional. Install it with: pipx install "strix-agent[vertex]"'
 )
@@ -225,11 +225,19 @@ def check_docker_installed() -> None:
 
 
 def _exception_messages(exc: BaseException) -> tuple[str, ...]:
-    messages = [str(exc)]
-    if exc.__cause__ is not None:
-        messages.append(str(exc.__cause__))
-    if exc.__context__ is not None:
-        messages.append(str(exc.__context__))
+    messages: list[str] = []
+    seen: set[int] = set()
+    stack: list[BaseException] = [exc]
+    while stack:
+        current = stack.pop()
+        if id(current) in seen:
+            continue
+        seen.add(id(current))
+        messages.append(str(current))
+        if current.__cause__ is not None:
+            stack.append(current.__cause__)
+        if current.__context__ is not None:
+            stack.append(current.__context__)
     return tuple(messages)
 
 

tests/test_provider_hints.py

@@ -46,6 +46,25 @@ def test_bedrock_boto3_hint_for_litellm_wrapped_connection_error() -> None:
     assert BEDROCK_EXTRA_NAME in hint
 
 
+def test_vertex_google_submodule_hint() -> None:
+    exc = ModuleNotFoundError("No module named 'google.auth'")
+    hint = _provider_import_hint(exc, VERTEX_MODEL)
+    assert hint is not None
+    assert INSTALL_EXTRA_COMMAND_FRAGMENT in hint
+    assert VERTEX_EXTRA_NAME in hint
+
+
+def test_vertex_google_hint_for_deeply_chained_error() -> None:
+    root = ModuleNotFoundError("No module named 'google.auth'")
+    middle = RuntimeError("provider init failed")
+    middle.__cause__ = root
+    exc = ConnectionError("litellm.APIConnectionError: request failed")
+    exc.__cause__ = middle
+    hint = _provider_import_hint(exc, VERTEX_MODEL)
+    assert hint is not None
+    assert VERTEX_EXTRA_NAME in hint
+
+
 def test_non_import_error_returns_none() -> None:
     assert _provider_import_hint(ConnectionError("boom"), "bedrock/whatever") is None