From 59562802cbdf08279bf9e8243acc3a69cc16b12e Mon Sep 17 00:00:00 2001
From: Prince Kumar <princer@google.com>
Date: Mon, 7 Sep 2026 18:39:09 +0000
Subject: [PATCH] timestamp optimization

---
 gcsfs/core.py            |  8 +++----
 gcsfs/tests/test_core.py | 46 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 49 insertions(+), 5 deletions(-)

diff --git a/gcsfs/core.py b/gcsfs/core.py
index f41c18bc6..8f3fa5e81 100644
--- a/gcsfs/core.py
+++ b/gcsfs/core.py
@@ -1081,11 +1081,9 @@ def modified(self, path):
     def created(self, path):
         return self.info(path)["ctime"]
 
-    def _parse_timestamp(self, timestamp):
-        assert timestamp.endswith("Z")
-        timestamp = timestamp[:-1]
-        timestamp = timestamp + "0" * (6 - len(timestamp.rsplit(".", 1)[-1]))
-        return datetime.fromisoformat(timestamp + "+00:00")
+    @staticmethod
+    def _parse_timestamp(timestamp):
+        return datetime.fromisoformat(timestamp.replace("Z", "+00:00"))
 
     async def _info(self, path, generation=None, **kwargs):
         """File information about this path."""
diff --git a/gcsfs/tests/test_core.py b/gcsfs/tests/test_core.py
index 8ba63b829..7b40a74df 100644
--- a/gcsfs/tests/test_core.py
+++ b/gcsfs/tests/test_core.py
@@ -3710,3 +3710,49 @@ def test_user_agent_includes_cache_type_and_source_in_read(gcs):
             for call in mock_session_request.call_args_list
         ]
         assert any("cache_type/readahead:d" in ua for ua in user_agents)
+
+
+@pytest.mark.parametrize(
+    "ts_str, expected_dt",
+    [
+        (
+            "2024-01-15T10:30:00.000Z",
+            datetime(2024, 1, 15, 10, 30, 0, 0, tzinfo=timezone.utc),
+        ),
+        (
+            "2024-01-15T11:45:00.123456Z",
+            datetime(2024, 1, 15, 11, 45, 0, 123456, tzinfo=timezone.utc),
+        ),
+        (
+            "2024-01-15T10:30:00Z",
+            datetime(2024, 1, 15, 10, 30, 0, 0, tzinfo=timezone.utc),
+        ),
+        (
+            "2024-01-15T10:30:00.12Z",
+            datetime(2024, 1, 15, 10, 30, 0, 120000, tzinfo=timezone.utc),
+        ),
+        (
+            "2024-01-15T10:30:00.1234Z",
+            datetime(2024, 1, 15, 10, 30, 0, 123400, tzinfo=timezone.utc),
+        ),
+    ],
+)
+def test_parse_timestamp_formats(gcs, ts_str, expected_dt):
+    assert gcs._parse_timestamp(ts_str) == expected_dt
+    assert GCSFileSystem._parse_timestamp(ts_str) == expected_dt
+
+
+def test_process_object_timestamps(gcs):
+    metadata = {
+        "name": "test_obj.txt",
+        "size": "50",
+        "timeCreated": "2024-01-15T10:30:00.000Z",
+        "updated": "2024-01-15T11:45:00.123456Z",
+    }
+    processed = gcs._process_object("my-bucket", metadata)
+    assert processed["ctime"] == datetime(
+        2024, 1, 15, 10, 30, 0, 0, tzinfo=timezone.utc
+    )
+    assert processed["mtime"] == datetime(
+        2024, 1, 15, 11, 45, 0, 123456, tzinfo=timezone.utc
+    )