chore: import upstream snapshot with attribution

tests/test_tracing_provider_safe_debug.py

@@ -0,0 +1,38 @@
+from __future__ import annotations
+
+import io
+import logging
+
+from agents.logger import logger
+from agents.tracing.provider import _safe_debug
+
+
+class _CapturingHandler(logging.Handler):
+    def __init__(self) -> None:
+        super().__init__()
+        self.records: list[logging.LogRecord] = []
+
+    def emit(self, record: logging.LogRecord) -> None:  # pragma: no cover - trivial
+        self.records.append(record)
+
+
+def test_safe_debug_skips_logging_when_handler_stream_closed() -> None:
+    original_handlers = logger.handlers[:]
+    original_propagate = logger.propagate
+
+    closed_stream = io.StringIO()
+    closed_handler = logging.StreamHandler(closed_stream)
+    closed_stream.close()
+
+    capturing_handler = _CapturingHandler()
+
+    try:
+        logger.handlers = [closed_handler, capturing_handler]
+        logger.propagate = False
+
+        _safe_debug("should not log")
+
+        assert capturing_handler.records == []
+    finally:
+        logger.handlers = original_handlers
+        logger.propagate = original_propagate