shutil.destinsrc(src,dst)

Checks if 'dst' starts with 'src', which can return a wrong result if
'dst' even starts with 'scr' but isn't really a subdirector of it. E.g.
(src=r'C:\data', dst=r'C:\data.old') returned true, although dst isn't a
subdirectory of src.

I tried to fix this creating the absolute paths of 'dst' and 'src'
appended the path seperator, if there wasn't one. Then did the check
again and now the result is correct.

See the diff file I've appended (and hopefully created correctly)

Can you write a test to catch this problem? The patch should preferably
be against the latest svn source.

The fix may get into 2.5 but definitely not into 2.4 because it's not a
security fix.

I added couple of test cases. Please see the patch shutil_destinsrc.patch.

Christian, do you mind testing on windows? I tested only on Linux.

Raghuram, you've been too fast ;-)

Your test matches the problem. I don't know if it happens on Linux, but
on my Win32 Installation the test 'test_destinsrc_2' fails with an 
AssertionError 'destinsrc() wrongly concluded that dst
(@test\srcdir.new) is in src (@test\srcdir)'.

Using the submitted patch everything comes out with 'Ok'.

I've appended the failing test output.

> Raghuram, you've been too fast ;-)

Sorry about that :-) and thanks for validating the test cases.

Using:  http://svn.python.org/projects/python/trunk  @  61127
OS Name:    Microsoft Windows XP Professional
OS Version: 5.1.2600 Service Pack 2 Build 2600

test_shutil
1 test OK.

On another note, I just completed building the docs in windows and
shutil.destinsrc does not appear to be documented.  I did notice this
description for shutil:

"The shutil module offers a number of high-level operations on files and
collections of files. In particular, functions are provided which
support file copying and removal."

I would have expected to find a function like this in os.path, not shutil.

On Fri, Feb 29, 2008 at 9:21 PM, Joseph Armbruster
<report@bugs.python.org> wrote:
>  On another note, I just completed building the docs in windows and
>  shutil.destinsrc does not appear to be documented.  I did notice this
>  description for shutil:

destinsrc() is an internal function used only in shutil.move().

Should it get a _ prepended to it then?

>  Should it get a _ prepended to it then?

Probably yes.

The function is just a one liner in 2.6 and it's used in one place only.
Let's move it into move().

Here's a patch that moves destinsrc into move.

>  The function is just a one liner in 2.6 and it's used in one place only.
>  Let's move it into move().

Isn't it clear from this issue's original description that there is a
bug in the one liner that needs fix ?

Can some one with commit privileges check in shutil_destinsrc.patch? The
change is rather simple and there is no point for issues such as these
to remain open for long time.

Our company recently rediscovered this bug in 2.5.2.  After a couple
hours of debugging, we realized the error message was incorrect and
found the bug in the destinsrc function.

This may not be a show-stopping bug, but it's non-obvious, annoying,
unnecessary, and very easy to fix.  Any chance of getting this into a
release?

On Tue, Jan 27, 2009 at 12:35 PM, James Cooper <report@bugs.python.org> wrote:
> This may not be a show-stopping bug, but it's non-obvious, annoying,
> unnecessary, and very easy to fix.  Any chance of getting this into a
> release?

Considering that the issue is idle for such a long time, I am not sure
if any one will check this in. Your best bet may be to bring this up
on python-dev. As you say, the problem is obvious and the fix is
simple.

Adding a test as well would be nice.

On Wed, Jan 28, 2009 at 5:13 PM, Antoine Pitrou <report@bugs.python.org> wrote:

shutil_destinsrc.patch has both the code chage and two test cases.
Actually test cases are much longer than the code itself :-).

Sorry, I had only given a quick look at Benjamin's patch, not yours.
Actually Benjamin's patch does not seem to address anything, which makes
things more confusing.

On Thu, Jan 29, 2009 at 1:32 PM, Antoine Pitrou <report@bugs.python.org> wrote:
> Sorry, I had only given a quick look at Benjamin's patch, not yours.
> Actually Benjamin's patch does not seem to address anything, which makes
> things more confusing.

True. It is all a bit unfortunate for such a small change to get
bogged down like this. I specifically asked about the patch proposed
by Christian and implemented by Benjamin (in msg63168) but no one
bothered to reply. Please look at my patch and see if you can apply
it. In fact, I even submitted it when Guido asked for some patches to
test codereview tool initially. It is at
http://codereview.appspot.com/841/show.

Committed, thanks!

Sorry to bring this fixed-closed issue back again.

I see that this was committed in a hurry.

Either, shutil.destinsrc should be Documented, there currently does not
exists any documentation to explain what destinsrc is supposed to do, or
the function should be made _destinsrc to be internal only. I vote for
the second approach of making it _destinsrc as it is used only in the
shutil.move().

If no action can be taken on a closed bug, I shall open a new one and
also attach a patch to make the method private.

Made private in r69415.

Thanks for the quick action. Really nice.