[tahoe-lafs-trac-stream] [Tahoe-LAFS] #2329: cp -r stops with an exception

[Tahoe-LAFS]

#2329: cp -r stops with an exception
-------------------------+-------------------------------------------------
     Reporter:  zooko    |      Owner:  warner
         Type:  defect   |     Status:  assigned
     Priority:  major    |  Milestone:  1.10.1
    Component:  code-    |    Version:  1.10.0
  frontend-cli           |   Keywords:  regression tahoe-cp review-needed
   Resolution:           |  release-blocker
Launchpad Bug:           |
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Comment (by warner):

 Two unexpected cases discovered during today's review:

 {{{
 1: cp FILE1 TARGETFILE/

 2: cp DIR1 DIR2 TARGETDIR
 }}}

 We decided the first should signal an error: the trailing slash will only
 be accepted if the target is directory-like (either a pre-existing
 directory, or something missing that will be created as a directory,
 either because the source is a directory, or because there are multiple
 sources). If the target is directory-like, the trailing slash will not
 affect the copying behavior.

 For the second, the realization was that this causes the contents of DIR1
 and DIR2 to be merged together in the TARGETDIR, and thus the order of the
 source arguments matters (presumeably DIR2's contents will overwrite those
 of DIR1). The same thing happens if you copy multiple files of the same
 name into a directory (`cp foo/file.txt bar/file.txt outdir`).

 We need to ensure the implementation preserves the order of the source
 arguments (I think my current patch does, but if I'd used a set instead of
 a dict, it would behave differently). We should also double-check that
 `/bin/cp` does the same thing.

--
Ticket URL: <https://tahoe-lafs.org/trac/tahoe-lafs/ticket/2329#comment:46>
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