From c512adc90d49b1dae3ae14c81826e03c9ea46ba5 Mon Sep 17 00:00:00 2001
From: Serhiy Storchaka <storchaka@gmail.com>
Date: Wed, 1 Apr 2015 16:54:05 +0300
Subject: [PATCH] Issue #23838: linecache now clears the cache and returns an
 empty result on MemoryError.

---
 Lib/linecache.py           |  6 +++++-
 Lib/test/test_linecache.py | 19 ++++++++++++++++---
 Misc/NEWS                  |  3 +++
 3 files changed, 24 insertions(+), 4 deletions(-)

diff --git a/Lib/linecache.py b/Lib/linecache.py
index e505b031240..884cbf493a4 100644
--- a/Lib/linecache.py
+++ b/Lib/linecache.py
@@ -37,8 +37,12 @@ def getlines(filename, module_globals=None):
 
     if filename in cache:
         return cache[filename][2]
-    else:
+
+    try:
         return updatecache(filename, module_globals)
+    except MemoryError:
+        clearcache()
+        return []
 
 
 def checkcache(filename=None):
diff --git a/Lib/test/test_linecache.py b/Lib/test/test_linecache.py
index 5fe0554572c..79157de43f6 100644
--- a/Lib/test/test_linecache.py
+++ b/Lib/test/test_linecache.py
@@ -126,8 +126,21 @@ class LineCacheTests(unittest.TestCase):
                 self.assertEqual(line, getline(source_name, index + 1))
                 source_list.append(line)
 
-def test_main():
-    support.run_unittest(LineCacheTests)
+    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)
+
 
 if __name__ == "__main__":
-    test_main()
+    unittest.main()
diff --git a/Misc/NEWS b/Misc/NEWS
index 33fc0ee3b02..58cdebdee26 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -21,6 +21,9 @@ Core and Builtins
 Library
 -------
 
+- Issue #23838: linecache now clears the cache and returns an empty result on
+  MemoryError.
+
 - Issue #18473: Fixed 2to3 and 3to2 compatible pickle mappings.  Fixed
   ambigious reverse mappings.  Added many new mappings.  Import mapping is no
   longer applied to modules already mapped with full name mapping.