From a686f36f0c6b4fbedd272d694ea9e5b6c41b2b2d Mon Sep 17 00:00:00 2001
From: maya-lukas <lukas@mayatravel.ai>
Date: Mon, 17 Aug 2026 10:34:49 +0200
Subject: [PATCH] fix(gemini): read the major version instead of matching
 "gemini-3"

The substring check would have reported Gemini 4 and later as pre-3,
reintroducing the same class of bug the moment Google ships an explicitly
versioned `gemini-4-*` model. Parsing the major version off the name and
comparing against 3 makes every later release work without a code change,
and it also excludes `gemini-2.5-flash-native-audio-latest` on version
rather than by special-casing the name.

The alias set now covers only names that carry no version at all.
---
 .../vertex_and_google_ai_studio_gemini.py     | 27 +++++++++----------
 ...test_vertex_and_google_ai_studio_gemini.py |  9 +++++++
 2 files changed, 21 insertions(+), 15 deletions(-)

diff --git a/litellm/llms/vertex_ai/gemini/vertex_and_google_ai_studio_gemini.py b/litellm/llms/vertex_ai/gemini/vertex_and_google_ai_studio_gemini.py
index bcc75d36482..f3de4aa30a5 100644
--- a/litellm/llms/vertex_ai/gemini/vertex_and_google_ai_studio_gemini.py
+++ b/litellm/llms/vertex_ai/gemini/vertex_and_google_ai_studio_gemini.py
@@ -2,6 +2,7 @@
 ## httpx client for vertex ai calls
 ## Initial implementation - covers gemini + image gen calls
 import json
+import re
 import time
 from collections.abc import Callable, Mapping, Sequence
 from copy import deepcopy
@@ -106,6 +107,8 @@ else:
     StreamingChoices = Any
 
 
+GEMINI_MAJOR_VERSION_PATTERN: Final[re.Pattern[str]] = re.compile(r"gemini-(\d+)")
+
 GEMINI_ROLLING_LATEST_ALIASES: Final[frozenset[str]] = frozenset(
     {
         "gemini-flash-latest",
@@ -266,23 +269,17 @@ class VertexGeminiConfig(VertexAIBaseConfig, BaseConfig):
     @staticmethod
     def _is_gemini_3_or_newer(model: str) -> bool:
         """
-        Check if the model is Gemini 3 Pro or newer.
+        Check if the model is Gemini 3 or newer, e.g. gemini-3-pro-preview,
+        gemini-3.1-flash, gemini-3.5-flash, and every later major version.
 
-        Gemini 3 models include:
-        - gemini-3-pro-preview
-        - gemini-3-flash
-        - gemini-3-flash-preview (Gemini 3 Flash)
-        - gemini-3.1-pro-preview, gemini-3.1-flash, gemini-3.1-flash-lite-preview
-        - gemini-3.5-flash
-        - Any future Gemini 3.x models
-        - GEMINI_ROLLING_LATEST_ALIASES, which resolve to Gemini 3.x and carry
-          no version number of their own. Matched by exact name, since
-          versioned names such as `gemini-2.5-flash-native-audio-latest` also
-          end in `-latest` yet are not Gemini 3
+        The major version is read off the model name, so Gemini 4 and beyond
+        satisfy this without a code change. Names carrying no version at all are
+        matched against GEMINI_ROLLING_LATEST_ALIASES, which always resolve to
+        the newest release of their tier.
         """
-        # Check for Gemini 3 models
-        if "gemini-3" in model:
-            return True
+        major_version: Final = GEMINI_MAJOR_VERSION_PATTERN.search(model)
+        if major_version is not None:
+            return int(major_version.group(1)) >= 3
         return model.split("/")[-1] in GEMINI_ROLLING_LATEST_ALIASES
 
     @staticmethod
diff --git a/tests/test_litellm/llms/vertex_ai/gemini/test_vertex_and_google_ai_studio_gemini.py b/tests/test_litellm/llms/vertex_ai/gemini/test_vertex_and_google_ai_studio_gemini.py
index caebca689b2..919d87cf1d2 100644
--- a/tests/test_litellm/llms/vertex_ai/gemini/test_vertex_and_google_ai_studio_gemini.py
+++ b/tests/test_litellm/llms/vertex_ai/gemini/test_vertex_and_google_ai_studio_gemini.py
@@ -2292,6 +2292,15 @@ def test_is_gemini_3_or_newer():
         == False
     )
 
+    # Later major versions must satisfy this without a code change
+    assert VertexGeminiConfig._is_gemini_3_or_newer("gemini-4-flash") == True
+    assert VertexGeminiConfig._is_gemini_3_or_newer("gemini-4.2-pro-preview") == True
+    assert VertexGeminiConfig._is_gemini_3_or_newer("gemini/gemini-10-flash") == True
+
+    # Unversioned names that are not rolling aliases stay excluded
+    assert VertexGeminiConfig._is_gemini_3_or_newer("gemini-embedding-001") == False
+    assert VertexGeminiConfig._is_gemini_3_or_newer("gemini-exp-1206") == False
+
 
 def test_thought_signature_fallback_for_rolling_latest_alias():
     """