On Tue, Feb 8, 2011 at 9:01 PM, Johan Corveleyn <jcor...@gmail.com> wrote:
> On Tue, Feb 8, 2011 at 1:28 PM, Daniel Shahaf <d...@daniel.shahaf.name> wrote:
>> I ran into this while trying to 'svn up' today, and managed to reproduce
>> it in another working copy:
>>
>> % svn revert -R .
>> % cat ./before
>> Index: subversion/include/svn_diff.h
>> ===================================================================
>> --- subversion/include/svn_diff.h (revision 1067829)
>> +++ subversion/include/svn_diff.h (working copy)
>> @@ -198,7 +198,7 @@
>> svn_error_t *
>> svn_diff_diff_2(svn_diff_t **diff,
>> void *diff_baton,
>> - const svn_diff_fns2_t *diff_fns,
>> + const svn_diff_fns2_t *diff_fns2,
>> apr_pool_t *pool);
>>
>> /** Given a vtable of @a diff_fns/@a diff_baton for reading datasources,
>> @@ -224,7 +224,7 @@
>> svn_error_t *
>> svn_diff_diff3_2(svn_diff_t **diff,
>> void *diff_baton,
>> - const svn_diff_fns2_t *diff_fns,
>> + const svn_diff_fns2_t *diff_fns2,
>> apr_pool_t *pool);
>>
>> /** Given a vtable of @a diff_fns/@a diff_baton for reading datasources,
>> @@ -252,7 +252,7 @@
>> svn_error_t *
>> svn_diff_diff4_2(svn_diff_t **diff,
>> void *diff_baton,
>> - const svn_diff_fns2_t *diff_fns,
>> + const svn_diff_fns2_t *diff_fns2,
>> apr_pool_t *pool);
>>
>> /** Given a vtable of @a diff_fns/@a diff_baton for reading datasources,
>> % patch -p0 < ./before
>> % svn up -q subversion/include/
>> % cat -n subversion/include/svn_diff.h | tail
>> 296 * Differences, similarities, and conflicts are described by lining up
>> 297 * "ranges" of data.
>> 298 *
>> 299 * @note These callbacks describe data ranges in units of "tokens".
>> 300 * A "token" is whatever you've defined it to be in your datasource
>> 301 * @c svn_diff_fns_t vtable.
>> 302 */
>> 303 typedef struct svn_diff_output_fns_t
>> 304 {
>> 305 /* Two-way and three-way diffs both call the first two output
>> functions: */
>> %
>
> Wow, weird. I can reproduce it too. I'm looking into it.
I'm continuing to try and fix this. For now, some thoughts I typed on IRC:
[22:29] <@jcorvel> ok, I'm starting to understand the truncating business
[22:30] <@jcorvel> diff is not affected, because it only outputs the
modified stuff from the diff chain
[22:30] <@jcorvel> (with their context)
[22:30] <@jcorvel> but diff3 outputs the entire chain ...
[22:31] <@ehu> which is missing its last record?
[22:31] <@jcorvel> yes
[22:31] <@ehu> evil
[22:32] <@jcorvel> I don't add the suffix to that diff chain (except
the first 50 lines, because I don't consider them part of the
identical suffix, to help diff/blame find a good way to output it)
[22:33] <@jcorvel> that was really an early optimization (when I was
only focusing on diff2): I saw that it didn't need the identical
suffix to do its work correctly
[22:33] <@jcorvel> that way, I could avoid counting lines while
scanning the identical suffix (which I do need to do for prefix
scanning, but I thought I could get away with it for the suffix)
[22:34] <@jcorvel> only later I included diff3 and diff4, and
considered everything ok when the test-suite passed
[22:34] <@jcorvel> if there would have been a merge test with more
than 50 common lines at the end, that test would have failed ...
[22:36] <@jcorvel> so, there are a couple of ways to fix this:
[22:36] <@jcorvel> 0. remove suffix scanning
[22:36] <@jcorvel> 1. make suffix scanning count lines, so it can
include a "common" diff chunk at the end of the chain, with the
correct nr of lines
[22:37] <@jcorvel> 2. have some way for a diff chunk in that chain to
indicate "until the end", and make svn_diff_file_output_merge2 cope
with that
[22:37] <@jcorvel> that's all I can think of right now
Any opinions on which solution I should pursue? For now, I'm looking
at how difficult 2. would be. But if it takes too long, maybe I should
simple do 0. to eliminate potential wc corruption for people working
with trunk svn ...
--
Johan
