[Svnmerge] [PATCH] preserving mods to renamed files/directories

[lsuvkne at onemodel.org]

>>> On Thu, Jun 21, 2007, Daniel Rall <dlr at collab.net> wrote: 
> The some (all?) of the failures were introduced by Blair's commit of
> some code to svnmerge.py, without any corresponding changes to
> svnmerge_tests.py.  While I haven't investigated, I'd guess that the
> tests need to be updated, since IIRC, Blair's commits were (all?) 
> intended as bug fixes.

Do you recall the approximate month, say, of those changes? If it seems likely
(with mods as per Dustin's suggestions) that the rest of my patch (or a
subset) will be useful to others, I will go ahead & try to fix those other 3
failing tests as well, but I'd like to look up what changes caused them.


> I have a counter‑proposal for Dustin, and for Luke (if interested):
> Would the two of you be willing to take over maintenance of
> svnmerge.py in the svn.collab.net repository?
> If so, I will mail you the details off‑list.

I am interested in learning any details; then I'll discuss w/ my employer. 
It could be a good thing; at a minimum saving me the time of breaking current
patch into chunks (assuming I can explain and modify it to Dustin's
satisfaction; I can still break it up if preferred).  I'm now in the process
of working through his suggestions.


One thing Dustin asked for was a textual description of the changes for the
list.  I'll provide that now while I work on the rest.  However, if the code
itself is unclear I think I should make it clearer.  I'm also happy to
elaborate on this in any way that you think would be helpful:

The heart of the changes (and the easiest place to start reading them, IMO)
are in action_merge(), where just before the script calls this:
    svn_command("merge --force -r
..I added a call to check_for_changes_to_preserve_across_merge(). This
function, and the functions it depends on, determine from "merge --dry-run"
output whether there are any matching "add/delete" pairs of statements
(representing renames) about to be applied, and for each of those renames,
determines from logs what file edits (diffs) and comments would be lost due to
the merge's deleting that file and replacing it. It saves the diffs to
temporary patch files, accumulates the comments, and returns  the information
back to action_merge().  Subsequently, the call in action_merge() to 
    svn_command("merge --force -r
..runs, and then for each file where edits were lost by the merge, it applies
the proper patch, and appends the otherwise "lost" comments to the file
svnmerge-commit-message.txt.

It's not necessarily pretty but seems to reduce the risk for our most common
scenarios.  There are some scenarios that I know it doesn't support, best
practices, tips from our internal wiki that I can share later if there's
interest.


FYI also, I had to make a number of changes to get the tests run on windows,
changing a number of things like a couple of regular expressions and the way
the environment variables are passed to subprocesses, line terminator issues,
etc.  Now windows gets only the same test 3 failures as linux.


Thanks,

-Luke