[3.8] bpo-25872: Fix KeyError in linecache when multithreaded (python…

…GH-18007) (pythonGH-20092) Backporting to 3.8 and adding a NEWS item (I should have added one to the master branch -- oh well).
miss-islington · May 29, 2020 · b86636b · b86636b
1 parent 6381ee0
commit b86636b
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Showing 2 changed files with 5 additions and 3 deletions.
diff --git a/Lib/linecache.py b/Lib/linecache.py
@@ -73,10 +73,10 @@ def checkcache(filename=None):
         try:
             stat = os.stat(fullname)
         except OSError:
-            del cache[filename]
+            cache.pop(filename, None)
             continue
         if size != stat.st_size or mtime != stat.st_mtime:
-            del cache[filename]
+            cache.pop(filename, None)
 
 
 def updatecache(filename, module_globals=None):
@@ -86,7 +86,7 @@ def updatecache(filename, module_globals=None):
 
     if filename in cache:
         if len(cache[filename]) != 1:
-            del cache[filename]
+            cache.pop(filename, None)
     if not filename or (filename.startswith('<') and filename.endswith('>')):
         return []
 

diff --git a/Misc/NEWS.d/next/Library/2020-05-14-13-25-36.bpo-25872.5D5538.rst b/Misc/NEWS.d/next/Library/2020-05-14-13-25-36.bpo-25872.5D5538.rst
@@ -0,0 +1,2 @@
+:mod:`linecache` could crash with a :exc:`KeyError` when accessed from multiple threads.
+Fix by Michael Graczyk.
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1,2 @@
		:mod:`linecache` could crash with a :exc:`KeyError` when accessed from multiple threads.
		Fix by Michael Graczyk.