Force refresh if session was closed (#1002)

Author: martindurant

.github/workflows/ci.yml

@@ -15,7 +15,7 @@ jobs:
           - "3.12"
           - "3.13"
           - "3.14"
-        aiobotocore-version: [">=2.5.4,<2.6.0", "<3.0.0", "<4.0.0"]
+        aiobotocore-version: [">=2.19.0,<2.20.0", "<3.0.0", "<4.0.0"]
 
     env:
       BOTO_CONFIG: /dev/null

requirements.txt

@@ -1,3 +1,3 @@
-aiobotocore>=2.5.4,<4.0.0
+aiobotocore>=2.19.0,<4.0.0
 fsspec==2026.1.0
 aiohttp!=4.0.0a0, !=4.0.0a1

s3fs/core.py

@@ -519,7 +519,12 @@ async def set_session(self, refresh=False, kwargs={}):
         >>> s3.connect(refresh=True)  # doctest: +SKIP
         """
         if self._s3 is not None and not refresh:
-            return self._s3
+            hsess = getattr(getattr(self._s3, "_endpoint", None), "http_session", None)
+            if hsess is not None:
+                if all(_.closed for _ in hsess._sessions.values()):
+                    refresh = True
+            if not refresh:
+                return self._s3
         logger.debug("Setting up s3fs instance")
 
         client_kwargs = self.client_kwargs.copy()

s3fs/tests/test_s3fs.py

@@ -3068,3 +3068,20 @@ def test_find_missing_ls(s3):
     listed_no_cache = s3_no_cache.ls(BASE, detail=False)
 
     assert set(listed_cached) == set(listed_no_cache)
+
+
+def test_session_close():
+    async def run_program(run):
+        s3 = s3fs.S3FileSystem(anon=True, asynchronous=True)
+        session = await s3.set_session()
+        files = await s3._ls(
+            "s3://noaa-hrrr-bdp-pds/hrrr.20140730/conus/"
+        )  # Random open data store
+        print(f"Number of files {len(files)}")
+        await session.close()
+
+    import aiobotocore.httpsession
+
+    aiobotocore.httpsession.AIOHTTPSession
+    asyncio.run(run_program(True))
+    asyncio.run(run_program(False))