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Need to resolve expected behavior of XFailing tests caused by tree conflicts (Issue #3209)

From: Paul Burba <ptburba_at_gmail.com>
Date: Tue, 20 Jan 2009 16:07:31 -0500

While reviewing issue #3209 I went through all the XFailing tests in
checkout_tests.py, update_tests.py, switch_tests.py, and
merge_tests.py looking for tests that fail because their expectations
were not adjusted to account for new tree conflict behavior.

Ignoring tests that fail for reasons unrelated to TCs, those that are
failing because they test unimplemented TC behavior, those that are
actively being worked on by others, and those I was able to fix, there
are six tests remaining that started failing with the advent of tree
conflict handling. These fall into four groups:

=======
GROUP 1
=======

checkout_tests.py 13 'co handles obstructing paths scheduled for add'
update_tests.py 34 'update handles obstructing paths scheduled for add'
switch_tests.py 21 'forced switch detects tree conflicts'

These three tests all cover behavior added in r22257:

  Enable up/sw/co to tolerate obstructions scheduled
  for addition without history.

  It's no longer an error when an update, switch, or
  checkout attempts to add a path that is already
  scheduled for addition *without* history in the WC.

  In the case of dirs, the directory is tolerated and
  reported as 'E'xisting.

  For files, if the obstruction is identical textually
  to the addition from the repos it is reported as
  'E'xisting, if it differs it's treated as a conflict.

  Property merges for both files and dirs are reported
  normally, i.e. ' ', 'C', 'G'.

  Obstructions scheduled for addition *with* history
  still result in an error.

See these three threads for more on this change:

  http://svn.haxx.se/dev/archive-2006-08/0336.shtml
  http://svn.haxx.se/dev/archive-2006-09/0362.shtml
  http://svn.haxx.se/dev/archive-2006-10/0708.shtml

All these tests start with two identical working copies, WC1 and WC2.
A set of files and directories are added to the repository via WC1.
Then the test adds the same set of paths *without* history to WC2.
These local adds in WC2 fall into 3 categories:

  A) Files textually identical to the files added to WC1.

     Previously we expected these obstructions to be
     tolerated, reported as 'E'xisting, and leave no trace
     after the checkout. Now however this produces a tree
     conflict of the 'local add, incoming add upon update'
     type.

  B) Files which differ textually from the files added
     to WC1.

     Prior to TC we expected these to be conflicts and they
     still are, but they are tree conflicts of the 'local
     add, incoming add upon update' type instead.

  C) Added directories that have no properties, the same
     properties, or conflicting properties with the the
     directories added to WC1.

     Prior to TC we expected all of these to be tolerated and
     reported as 'E'xisting, though their properties might mer'G'e
     or 'C'onflict. That is still the case.

The desired behavior in cases A) & B) need to be resolved. Do we want
to support the behavior introduced in r22257 that tolerates
obstructing adds with history or remove it? The behavior in case C)
should follow the decision on A) and B), files and directories are
treated consistently I think.

There is also a regression in these tests. Taking checkout_tests.py
13 for example, after the above cases are covered, the test does a
URL-to-URL copy of A/D/G to A/D/M and then does a WC-to-WC copy of
A/D/H
to A/D/M, leaving us with (I'm simplifying here, the test does some other stuff
as well):

  trunk>svn st checkout_tests-13 -u
          * checkout_tests-13\A\D\M\pi
          * checkout_tests-13\A\D\M\rho
          * checkout_tests-13\A\D\M\tau
  A + * - checkout_tests-13\A\D\M
          * 1 checkout_tests-13\A\D
  Status against revision: 3

Then when we try to update (the test does a checkout but the effect is the same)
we get this error:

  trunk>svn up checkout_tests-13
  ..\..\..\subversion\libsvn_wc\adm_files.c:672: (apr_err=155000)
  svn: Revision 3 doesn't match existing revision 1 in 'checkout_tests-13/A/D/M'

=======
GROUP 2
=======

update_tests.py 31 'forced up fails with some types of obstructions'

This test fails when we a (--forced) update tries to add a directory
when a versioned directory of the same name already exists.
Admittedly this is quite a contrived situation: The test adds a
directory A/C/I in r2, updates A/C to r1, then checks out %URL%/A/C/I
directly to A/C/I in the WC. This leaves us with a situation where
A/C thinks A/C/I is some unversioned item:

>svn st update_tests-31.backup\A\C -v
                   1 1 jrandom update_tests-31.backup\A\C
  ? update_tests-31.backup\A\C\I

>svn st update_tests-31.backup\A\C\I -v
                   2 2 jrandom update_tests-31.backup\A\C\I

Prior to TC we expected this to fail with an error:

  svn: Failed to add directory 'update_tests-31.backup\A\C\I':
  a versioned directory of the same name already exists

This is now a tree conflict:

>svn up --force update_tests-31.backup
     C update_tests-31.backup\A\C\I
  At revision 2.
  Summary of conflicts:
    Tree conflicts: 1

>svn st update_tests-31.backup
  ? C update_tests-31.backup\A\C\I
> local add, incoming add upon update

It strikes me that *both* of these behaviors are probably wrong.
Shouldn't the update simply tolerate A/C/I's presence and simply bring
A/C up to r2? Though if A/C/I pointed to a different location then
there should be an error, but what?

FWIW this doesn't seem a very common use case. The old behavior was
added by me back with the r20945 'takeover' functionality, and IIRC it
was simply because this was a possibility and the code had to do
*something* in this case.

=======
GROUP 3
=======

update_tests.py 50 'tree conflicts on update 2.3'

This tests that updates of tree conflicted paths report the TCs as
skipped, but what exactly does 2.3 refer to?

http://svn.collab.net/repos/svn/trunk/notes/tree-conflicts/use-cases.txt
has use case 2, but there are no subsections. This appears to be an
test for issue #3329,
http://subversion.tigris.org/issues/show_bug.cgi?id=3329#desc2, and as
I noted there, many of the cases this test covers now work and report
skips:

  a) Directory tree conflict victim is updated

  b) File tree conflict victim is updated

  c) Directory within a tree conflict victim is updated

  d) Fle within a tree conflict victim is updated
     (file doesn't exist in the repos)

What doesn't work is:

  e) A file within a tree conflict victim is updated
    (file doesn't exist in the repos but shows as
    locally added)

  f) Directory update target is not tree conflicted
     but has tree conflicted file child.

  g) Directory update target is not tree conflicted
     but has tree conflicted dir child.

In all three of these cases the update prints no skip notifications,
the 'At revision N.' is the only output. The status of the WC is the
same in each case, so no harm is done outside of the missing skip
notifications.

So, is this simply a test for issue #3329 or is there anything else to
consider?

=======
GROUP 4
=======

merge_tests.py 20 'merge into missing must not break working copy'

In r31326 (on the tree-conflicts branch) this test was changed to
expect a tree conflict when merging into a directory that has a
missing subtree (to be clear, this is missing in the '!' removed by a
non-svn command sense of missing). The current (and pre-TC?) behavior
was to report the missing subtrees as skipped.

Why is a tree conflict expected here? We report the files as skipped
during the merge and they show as missing in status. You can't even
commit the change without updating first to get the missing items
back. Yes, at that point you could commit and most likely you won't
have what you want in the repos, but you must willfully ignore a lot
of warnings that something is not quite right.

This case mentioned in the 'SCENARIO PLAYGROUND' in
http://svn.collab.net/repos/svn/trunk/notes/tree-conflicts/scratch-pad.txt,
but there is no conclusion:

'svn merge' pulls file modification atop missing file

  NOW: "Skipped missing target" message.

  NEW:

There is also some mention of this in
http://svn.collab.net/repos/svn/trunk/notes/tree-conflicts/design-overview.txt

  * Pre-existing obstructions (status "~") or missing items ("!") should be
    detected first, before attempting to apply the change, and abort the
    operation.

What is the latest thinking on this scenario?

~~~~~

Thoughts from TC savvy folks and anyone else are appreciated.

Thanks,

Paul
Received on 2009-01-20 22:08:40 CET

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