From 596cc4c0c27d2079aef1ad3b72b9cdaef29e472c Mon Sep 17 00:00:00 2001
From: Kolade Fajimi <107228310+koladefaj@users.noreply.github.com>
Date: Tue, 8 Sep 2026 07:20:45 +0100
Subject: [PATCH] refactor(vertex): log the credential source decision where it
 is made

---
 litellm/llms/vertex_ai/credentials_source.py | 9 +++++++--
 litellm/llms/vertex_ai/vertex_llm_base.py    | 7 -------
 2 files changed, 7 insertions(+), 9 deletions(-)

diff --git a/litellm/llms/vertex_ai/credentials_source.py b/litellm/llms/vertex_ai/credentials_source.py
index b59520d0fbe..a973d60d21c 100644
--- a/litellm/llms/vertex_ai/credentials_source.py
+++ b/litellm/llms/vertex_ai/credentials_source.py
@@ -6,6 +6,7 @@ it is decides what a failure means, so the two are told apart by the shape of th
 each failure is returned as its own case instead of collapsing into one parse error.
 """
 
+import os
 from collections.abc import Mapping
 from dataclasses import dataclass
 from typing import Final, NoReturn, TypeAlias
@@ -80,7 +81,7 @@ def _read_json_file(path: str) -> _VertexCredentialsFile:
     return VertexCredentialsJson(parsed)
 
 
-def is_inline_credentials_json(credentials: str) -> bool:
+def _is_inline_credentials_json(credentials: str) -> bool:
     """Whether *credentials* carries the JSON itself rather than a path to a file holding it."""
     return credentials.lstrip().startswith("{")
 
@@ -92,7 +93,11 @@ def load_vertex_credentials_source(credentials: str) -> VertexCredentialsSource:
     failure recognisable: `os.path.exists()` answers False for an unreadable path as well as
     an absent one, so both used to reach the inline branch and be reported as malformed JSON.
     """
-    if not is_inline_credentials_json(credentials):
+    inline_first: Final = _is_inline_credentials_json(credentials)
+    verbose_logger.debug(
+        "Vertex: Loading vertex credentials, is_file_path=%s, current dir %s", not inline_first, os.getcwd()
+    )
+    if not inline_first:
         return _read_json_file(credentials)
 
     inline: Final = _parse_json_object(credentials)
diff --git a/litellm/llms/vertex_ai/vertex_llm_base.py b/litellm/llms/vertex_ai/vertex_llm_base.py
index eaddd3a9b58..e0886993109 100644
--- a/litellm/llms/vertex_ai/vertex_llm_base.py
+++ b/litellm/llms/vertex_ai/vertex_llm_base.py
@@ -6,7 +6,6 @@ Handles Authentication and generating request urls for Vertex AI and Google AI S
 
 import asyncio
 import json
-import os
 import threading
 from collections.abc import Mapping
 from typing import TYPE_CHECKING, Any, Final, Literal, Protocol
@@ -28,7 +27,6 @@ from .common_utils import (
 )
 from .credentials_source import (
     VertexCredentialsJson,
-    is_inline_credentials_json,
     load_vertex_credentials_source,
     raise_vertex_credentials_failure,
 )
@@ -134,11 +132,6 @@ class VertexBase:
         if credentials is not None:
             if isinstance(credentials, str):
                 source: Final = load_vertex_credentials_source(credentials)
-                verbose_logger.debug(
-                    "Vertex: Loading vertex credentials, is_file_path=%s, current dir %s",
-                    not is_inline_credentials_json(credentials),
-                    os.getcwd(),
-                )
                 if not isinstance(source, VertexCredentialsJson):
                     raise_vertex_credentials_failure(source)
                 json_obj: Mapping[str, object] = source.value