From c892e7cce6a23b1768373f136ad79ed185198d5e Mon Sep 17 00:00:00 2001
From: Varun Sripad <varunsripad@Varuns-MacBook-Air.local>
Date: Wed, 28 Jan 2026 16:45:41 -0600
Subject: [PATCH] fix(litellm_logging.py): prevent double logging of
 success/failure events (Fixes #19929)

---
 litellm/litellm_core_utils/litellm_logging.py | 19 ++++++
 .../test_prometheus_double_count.py           | 65 +++++++++++++++++++
 2 files changed, 84 insertions(+)
 create mode 100644 tests/test_litellm/test_prometheus_double_count.py

diff --git a/litellm/litellm_core_utils/litellm_logging.py b/litellm/litellm_core_utils/litellm_logging.py
index 0d9245a686a..2c7a5198163 100644
--- a/litellm/litellm_core_utils/litellm_logging.py
+++ b/litellm/litellm_core_utils/litellm_logging.py
@@ -1492,6 +1492,25 @@ class Logging(LiteLLMLoggingBaseClass):
         stream: bool = False,
     ) -> bool:
         try:
+            # Check for double logging
+            # If we are checking for success, check if EITHER async or sync success has explicitly been logged
+            if "success" in event_type:
+                if (
+                    self.model_call_details.get("has_logged_async_success", False)
+                    is True
+                    or self.model_call_details.get("has_logged_sync_success", False)
+                    is True
+                ):
+                    return False
+            elif "failure" in event_type:
+                if (
+                    self.model_call_details.get("has_logged_async_failure", False)
+                    is True
+                    or self.model_call_details.get("has_logged_sync_failure", False)
+                    is True
+                ):
+                    return False
+
             if self.model_call_details.get(f"has_logged_{event_type}", False) is True:
                 return False
 
diff --git a/tests/test_litellm/test_prometheus_double_count.py b/tests/test_litellm/test_prometheus_double_count.py
new file mode 100644
index 00000000000..38acd5d066f
--- /dev/null
+++ b/tests/test_litellm/test_prometheus_double_count.py
@@ -0,0 +1,65 @@
+import pytest
+import time
+from unittest.mock import MagicMock
+from litellm.litellm_core_utils.litellm_logging import Logging
+
+def test_should_run_logging_double_count_reproduction():
+    """
+    Reproduction for Issue #19929.
+    
+    Verifies that 'should_run_logging' currently returns True for both 'async_success' 
+    and 'sync_success' for the same request, leading to double counting.
+    """
+    logging_obj = Logging(
+        model="gpt-3.5-turbo", 
+        messages=[{"role": "user", "content": "hello"}],
+        stream=False,
+        call_type="completion",
+        start_time=time.time(),
+        litellm_call_id="test_id",
+        function_id="test_func_id"
+    )
+    logging_obj.model_call_details = {}
+    
+    # 1. First call: async_success
+    should_run_async = logging_obj.should_run_logging(event_type="async_success", stream=False)
+    assert should_run_async is True
+    
+    # Simulate the handler running and setting the flag
+    logging_obj.model_call_details["has_logged_async_success"] = True
+    
+    # 2. Second call: sync_success (triggered by fallback logic)
+    should_run_sync = logging_obj.should_run_logging(event_type="sync_success", stream=False)
+    
+    # BUG: This currently returns True, causing double logging
+    # assert should_run_sync is True 
+    
+    # Updated to assert correct behavior (Fix for #19929)
+    assert should_run_sync is False
+
+def test_should_run_logging_double_count_fix_expectation():
+    """
+    This test currently FAILS if the bug exists. 
+    It represents the Desired Behavior.
+    """
+    logging_obj = Logging(
+        model="gpt-3.5-turbo", 
+        messages=[{"role": "user", "content": "hello"}],
+        stream=False,
+        call_type="completion",
+        start_time=time.time(),
+        litellm_call_id="test_id",
+        function_id="test_func_id"
+    )
+    logging_obj.model_call_details = {}
+    
+    # 1. First call: async_success
+    should_run_async = logging_obj.should_run_logging(event_type="async_success", stream=False)
+    assert should_run_async is True
+    logging_obj.model_call_details["has_logged_async_success"] = True
+    
+    # 2. Second call: sync_success
+    should_run_sync = logging_obj.should_run_logging(event_type="sync_success", stream=False)
+    
+    # DESIRED: Should be False to prevent double counting
+    assert should_run_sync is False