[New-bugs-announce] [issue17051] Memory leak in os.path.isdir under Windows

[Robert Xiao]

New submission from Robert Xiao:

[From http://stackoverflow.com/questions/12648737/huge-memory-leak-in-repeated-os-path-isdir-calls]

os.path.isdir() leaks memory under Windows in Python 2.7. The core cause is this snippet:

Modules/posixmodule.c:4226:
    if (!PyArg_ParseTuple(args, "et:_isdir",
                          Py_FileSystemDefaultEncoding, &path))
        return NULL;

    attributes = GetFileAttributesA(path);
    if (attributes == INVALID_FILE_ATTRIBUTES)
        Py_RETURN_FALSE;

check:
    if (attributes & FILE_ATTRIBUTE_DIRECTORY)
        Py_RETURN_TRUE;
    else
        Py_RETURN_FALSE;


The buffer returned by the "et" ParseTuple format must be freed after use. Since it isn't freed, we get a memory leak here.

Patch:

--- a/Modules/posixmodule.c	Mon Apr 09 19:04:04 2012 -0400
+++ b/Modules/posixmodule.c	Sun Jan 27 04:10:34 2013 -0500
@@ -4226,6 +4226,7 @@
         return NULL;
 
     attributes = GetFileAttributesA(path);
+    PyMem_Free(path);
     if (attributes == INVALID_FILE_ATTRIBUTES)
         Py_RETURN_FALSE;

----------
components: Library (Lib)
messages: 180754
nosy: nneonneo
priority: normal
severity: normal
status: open
title: Memory leak in os.path.isdir under Windows
type: resource usage
versions: Python 2.6, Python 2.7

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<http://bugs.python.org/issue17051>
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