Re: svn commit: r1440966 - in /subversion/trunk/subversion: libsvn_client/merge.c tests/cmdline/merge_tests.py tests/cmdline/merge_tree_conflict_tests.py tests/cmdline/tree_conflict_tests.py

On Thu, Jan 31, 2013 at 9:12 AM, <rhuijben_at_apache.org> wrote:
> Author: rhuijben
> Date: Thu Jan 31 14:12:53 2013
> New Revision: 1440966
>
> URL: http://svn.apache.org/viewvc?rev=1440966&view=rev
> Log:
> In the merge handling: make the tree conflict detection for directories work
> like that in the update editor: Detect tree conflicts on entering every node,
> but only report conflicts on actual changes.
>
> This simplifies and brings together the obstruction logic, avoids touching
> unrelated nodes just for testing and makes the tree conflicts more reliable.
>
> The next step will be to hook the file code to this same system.
>
> This patch adds a few notifications for unversioned/missing obstructions
> to make these reports more similar to those of tree conflicts.
.
<SNIP>
.
> def at_directory_external(sbox):
> "tree conflict at directory external"

Only indirectly related to this commit, but one thing I noticed while
looking at it was a change from 1.7 in the way we report merge skips
within subtrees we don't have read access to.

Say we have full read access to our merge source (^/A), but only
partial read access to our merge target (^/branch-1):

authz:
[[[
[/]
* = rw
[/branch-1/C]
* =
]]]

Full disclosure: The above is an unusual[1] authz setup. We already
know the corresponding tree structure in the source, so I don't think
this is so much a security concern as it is a signal-to-noise problem
where potentially a *lot* of skip notifications can be generated.

Assume a merge wants to apply changes from ^/A into the restricted
subtree of the branch:

1.8-dev>svn diff --summarize -c3
A A\C\J\K\L\M\N\O\P\Q\R\S\T\U\V\W\X\Y\Z\nu
A A\C\J\K\L\M\N\O\P\Q\R\S\T\U\V\W\X\Y\Z
A A\C\J\K\L\M\N\O\P\Q\R\S\T\U\V\W\X\Y
A A\C\J\K\L\M\N\O\P\Q\R\S\T\U\V\W\X
A A\C\J\K\L\M\N\O\P\Q\R\S\T\U\V\W
A A\C\J\K\L\M\N\O\P\Q\R\S\T\U\V
A A\C\J\K\L\M\N\O\P\Q\R\S\T\U
A A\C\J\K\L\M\N\O\P\Q\R\S\T
A A\C\J\K\L\M\N\O\P\Q\R\S
A A\C\J\K\L\M\N\O\P\Q\R
A A\C\J\K\L\M\N\O\P\Q
A A\C\J\K\L\M\N\O\P
A A\C\J\K\L\M\N\O
A A\C\J\K\L\M\N
A A\C\J\K\L\M
A A\C\J\K\L
A A\C\J\K
A A\C\J

In 1.7 we are only told that the root of the missing subtree is skipped:

1.7.9-dev>svn merge ^^/A branch-1 -c3
Skipped missing target: 'branch-1\C'
--- Recording mergeinfo for merge of r3 into 'branch-1':
 U branch-1
Summary of conflicts:
  Skipped paths: 1

But with 1.8-dev we see the whole source tree structure revealed via
notifications:

1.8-dev>svn merge ^^/A branch-1 -c3
Skipped missing target: 'branch-1\C'
Skipped 'branch-1\C\J\K\L\M\N\O\P\Q\R\S\T\U\V\W\X\Y\Z\nu'
Skipped missing target: 'branch-1\C\J\K\L\M\N\O\P\Q\R\S\T\U\V\W\X\Y\Z'
Skipped missing target: 'branch-1\C\J\K\L\M\N\O\P\Q\R\S\T\U\V\W\X\Y'
Skipped missing target: 'branch-1\C\J\K\L\M\N\O\P\Q\R\S\T\U\V\W\X'
Skipped missing target: 'branch-1\C\J\K\L\M\N\O\P\Q\R\S\T\U\V\W'
Skipped missing target: 'branch-1\C\J\K\L\M\N\O\P\Q\R\S\T\U\V'
Skipped missing target: 'branch-1\C\J\K\L\M\N\O\P\Q\R\S\T\U'
Skipped missing target: 'branch-1\C\J\K\L\M\N\O\P\Q\R\S\T'
Skipped missing target: 'branch-1\C\J\K\L\M\N\O\P\Q\R\S'
Skipped missing target: 'branch-1\C\J\K\L\M\N\O\P\Q\R'
Skipped missing target: 'branch-1\C\J\K\L\M\N\O\P\Q'
Skipped missing target: 'branch-1\C\J\K\L\M\N\O\P'
Skipped missing target: 'branch-1\C\J\K\L\M\N\O'
Skipped missing target: 'branch-1\C\J\K\L\M\N'
Skipped missing target: 'branch-1\C\J\K\L\M'
Skipped missing target: 'branch-1\C\J\K\L'
Skipped missing target: 'branch-1\C\J\K'
Skipped missing target: 'branch-1\C\J'
--- Recording mergeinfo for merge of r3 into 'branch-1':
 U branch-1
Summary of conflicts:
  Skipped paths: 19

To be clear, this *doesn't* happen when we don't have access to the
corresponding subtree in the source, regardless of the access we have
to the corresponding subtree in the target:

authz
[[[
[/branch-1/C]
* =
[/A/C]
* =
[/]
* = rw
]]]

1.8-dev>svn merge ^^/A branch-1 -c3
Skipped missing target: 'branch-1\C'
--- Recording mergeinfo for merge of r3 into 'branch-1':
 U branch-1
Summary of conflicts:
  Skipped paths: 1

authz:
[[[
[/branch-1/C]
* = rw
[/A/C]
* =
[/]
* = rw
]]]

1.8-dev>svn merge ^^/A branch-1 -c3
Skipped missing target: 'branch-1\C'
--- Recording mergeinfo for merge of r3 into 'branch-1':
 U branch-1\C
 U branch-1
Summary of conflicts:
  Skipped paths: 1

[1] Seriously, if nobody has ever seen a setup like this in the wild
this is probably a non-issue.

-- 
Paul T. Burba
CollabNet, Inc. -- www.collab.net -- Enterprise Cloud Development
Skype: ptburba