From da965db5cb460aef9f0341556a2bd4ad5f61846c Mon Sep 17 00:00:00 2001
From: Jeremiah Lowin <153965+jlowin@users.noreply.github.com>
Date: Wed, 7 Jan 2026 14:29:56 -0500
Subject: [PATCH] Fix unawaited coroutine warning and treat as test error
 (#2806)

---
 pyproject.toml               | 3 +++
 src/fastmcp/client/client.py | 2 ++
 2 files changed, 5 insertions(+)

diff --git a/pyproject.toml b/pyproject.toml
index 6b41c1ae3..22fdd6b68 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -110,6 +110,9 @@ filterwarnings = [
     # Suppress OAuth in-memory token storage warnings in tests
     # Tests intentionally use ephemeral storage; this warning is for end users
     "ignore:Using in-memory token storage:UserWarning",
+    # Treat unawaited coroutine warnings as errors - these are almost always bugs
+    "error:coroutine .* was never awaited:RuntimeWarning",
+    "error:Exception ignored in.*coroutine:pytest.PytestUnraisableExceptionWarning",
 ]
 timeout = 5
 env = [
diff --git a/src/fastmcp/client/client.py b/src/fastmcp/client/client.py
index 4b8488280..910b6d998 100644
--- a/src/fastmcp/client/client.py
+++ b/src/fastmcp/client/client.py
@@ -686,6 +686,8 @@ class Client(Generic[ClientTransportT]):
 
         # If session task already failed, raise immediately
         if session_task.done():
+            # Close the coroutine to avoid "was never awaited" warning
+            coro.close()
             exc = session_task.exception()
             if exc:
                 raise exc