Issue #23838: linecache now clears the cache and returns an empty result on

MemoryError.

Lib/linecache.py

@@ -40,11 +40,14 @@ def getlines(filename, module_globals=None):
 
     if filename in cache:
         entry = cache[filename]
-        if len(entry) == 1:
-            return updatecache(filename, module_globals)
-        return cache[filename][2]
-    else:
+        if len(entry) != 1:
+            return cache[filename][2]
+
+    try:
         return updatecache(filename, module_globals)
+    except MemoryError:
+        clearcache()
+        return []
 
 
 def checkcache(filename=None):

Lib/test/test_linecache.py

@@ -169,9 +169,21 @@ class LineCacheTests(unittest.TestCase):
             linecache.lazycache(NONEXISTENT_FILENAME, globals()))
         self.assertEqual(4, len(linecache.cache[NONEXISTENT_FILENAME]))
 
+    def test_memoryerror(self):
+        lines = linecache.getlines(FILENAME)
+        self.assertTrue(lines)
+        def raise_memoryerror(*args, **kwargs):
+            raise MemoryError
+        with support.swap_attr(linecache, 'updatecache', raise_memoryerror):
+            lines2 = linecache.getlines(FILENAME)
+        self.assertEqual(lines2, lines)
+
+        linecache.clearcache()
+        with support.swap_attr(linecache, 'updatecache', raise_memoryerror):
+            lines3 = linecache.getlines(FILENAME)
+        self.assertEqual(lines3, [])
+        self.assertEqual(linecache.getlines(FILENAME), lines)
 
-def test_main():
-    support.run_unittest(LineCacheTests)
 
 if __name__ == "__main__":
-    test_main()
+    unittest.main()

Misc/NEWS

@@ -13,6 +13,9 @@ Core and Builtins
 Library
 -------
 
+- Issue #23838: linecache now clears the cache and returns an empty result on
+  MemoryError.
+
 - Issue #10395: Added os.path.commonpath(). Implemented in posixpath and ntpath.
   Based on patch by Rafik Draoui.