From a3401654e15da7c0ac981b5c5f69a64aa05694b0 Mon Sep 17 00:00:00 2001
From: Benjamin Peterson <benjamin@python.org>
Date: Fri, 21 May 2010 21:45:16 +0000
Subject: [PATCH] Merged revisions 81432 via svnmerge from
 svn+ssh://pythondev@svn.python.org/python/trunk

........
  r81432 | benjamin.peterson | 2010-05-21 16:31:24 -0500 (Fri, 21 May 2010) | 1 line

  ensure the last line has a trailing newline #8782
........
---
 Lib/linecache.py           |  2 ++
 Lib/test/test_linecache.py | 14 ++++++++++++++
 Misc/NEWS                  |  3 +++
 3 files changed, 19 insertions(+)

diff --git a/Lib/linecache.py b/Lib/linecache.py
index e7c33e1464..c9998515b2 100644
--- a/Lib/linecache.py
+++ b/Lib/linecache.py
@@ -133,6 +133,8 @@ def updatecache(filename, module_globals=None):
     except IOError, msg:
 ##      print '*** Cannot open', fullname, ':', msg
         return []
+    if lines and not lines[-1].endswith('\n'):
+        lines[-1] += '\n'
     size, mtime = stat.st_size, stat.st_mtime
     cache[filename] = size, mtime, lines, fullname
     return lines
diff --git a/Lib/test/test_linecache.py b/Lib/test/test_linecache.py
index 18206d2be5..945d7689cf 100644
--- a/Lib/test/test_linecache.py
+++ b/Lib/test/test_linecache.py
@@ -31,6 +31,11 @@ a = f()
 
 '''
 
+SOURCE_3 = '''
+def f():
+    return 3''' # No ending newline
+
+
 class LineCacheTests(unittest.TestCase):
 
     def test_getline(self):
@@ -63,6 +68,15 @@ class LineCacheTests(unittest.TestCase):
         empty = linecache.getlines('a/b/c/__init__.py')
         self.assertEquals(empty, [])
 
+    def test_no_ending_newline(self):
+        try:
+            with open(support.TESTFN, "w") as fp:
+                fp.write(SOURCE_3)
+            lines = linecache.getlines(support.TESTFN)
+            self.assertEqual(lines, ["\n", "def f():\n", "    return 3\n"])
+        finally:
+            support.unlink(support.TESTFN)
+
     def test_clearcache(self):
         cached = []
         for entry in TESTS:
diff --git a/Misc/NEWS b/Misc/NEWS
index 2fc7890de4..6b97a3dec3 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -55,6 +55,9 @@ C-API
 Library
 -------
 
+- Issue #8782: Add a trailing newline in linecache.updatecache to the last line
+  of files without one.
+
 - Issue #8729: Return NotImplemented from collections.Mapping.__eq__ when
   comparing to a non-mapping.
 
-- 
2.50.0