Issue #11235: Fix OverflowError when trying to import a source file whose modification time doesn't fit in a 32-bit timestamp.
diff --git a/Lib/importlib/test/source/test_file_loader.py b/Lib/importlib/test/source/test_file_loader.py
index de1c4d8..89990be 100644
--- a/Lib/importlib/test/source/test_file_loader.py
+++ b/Lib/importlib/test/source/test_file_loader.py
@@ -128,6 +128,23 @@
             pycache = os.path.dirname(imp.cache_from_source(file_path))
             shutil.rmtree(pycache)
 
+    def test_timestamp_overflow(self):
+        # When a modification timestamp is larger than 2**32, it should be
+        # truncated rather than raise an OverflowError.
+        with source_util.create_modules('_temp') as mapping:
+            source = mapping['_temp']
+            compiled = imp.cache_from_source(source)
+            with open(source, 'w') as f:
+                f.write("x = 5")
+            os.utime(source, (2 ** 33, 2 ** 33))
+            loader = _bootstrap._SourceFileLoader('_temp', mapping['_temp'])
+            mod = loader.load_module('_temp')
+            # Sanity checks.
+            self.assertEqual(mod.__cached__, compiled)
+            self.assertEqual(mod.x, 5)
+            # The pyc file was created.
+            os.stat(compiled)
+
 
 class BadBytecodeTest(unittest.TestCase):
 
diff --git a/Lib/test/test_import.py b/Lib/test/test_import.py
index c695757..33277d7 100644
--- a/Lib/test/test_import.py
+++ b/Lib/test/test_import.py
@@ -310,6 +310,18 @@
             """))
         script_helper.assert_python_ok(testfn)
 
+    def test_timestamp_overflow(self):
+        # A modification timestamp larger than 2**32 should not be a problem
+        # when importing a module (issue #11235).
+        source = TESTFN + ".py"
+        compiled = imp.cache_from_source(source)
+        with open(source, 'w') as f:
+            pass
+        os.utime(source, (2 ** 33, 2 ** 33))
+        __import__(TESTFN)
+        # The pyc file was created.
+        os.stat(compiled)
+
 
 class PycRewritingTests(unittest.TestCase):
     # Test that the `co_filename` attribute on code objects always points