fix: Reject a poll interval longer than the runtime can wait

Author: kinyoklion

ldclient/integrations/overrides.py

@@ -27,6 +27,7 @@
 """
 
 import math
+import threading
 from typing import List, Optional, Union
 
 from ldclient.config import DataSourceBuilderConfig, OverrideSourceBuilder
@@ -128,12 +129,15 @@ def poll_interval(self, seconds: float) -> 'FileOverrideSourceBuilder':
 
         :param seconds: the interval in seconds
         :raises TypeError: when the interval is not a number
-        :raises ValueError: when the interval is not a finite number
+        :raises ValueError: when the interval is not a finite number, or is longer than the
+            runtime can wait
         """
         if isinstance(seconds, bool) or not isinstance(seconds, (int, float)):
             raise TypeError("the poll interval must be a number of seconds")
         if not math.isfinite(seconds):
             raise ValueError("the poll interval must be a finite number of seconds")
+        if seconds > threading.TIMEOUT_MAX:
+            raise ValueError("the poll interval must not exceed %s seconds" % threading.TIMEOUT_MAX)
         self.__poll_interval = seconds
         return self
 

ldclient/testing/integrations/test_file_override_source.py

@@ -171,6 +171,12 @@ def test_builder_rejects_a_poll_interval_that_is_not_a_number(seconds):
         FileOverrideSourceBuilder(['a']).poll_interval(seconds)
 
 
+def test_builder_rejects_a_poll_interval_longer_than_the_runtime_can_wait():
+    with pytest.raises(ValueError) as excinfo:
+        FileOverrideSourceBuilder(['a']).poll_interval(1e20)
+    assert 'must not exceed' in str(excinfo.value)
+
+
 @pytest.mark.parametrize('seconds', [float('nan'), float('inf'), float('-inf')], ids=['nan', 'inf', '-inf'])
 def test_builder_rejects_a_poll_interval_that_is_not_finite(seconds):
     with pytest.raises(ValueError):