Re: [egit-dev] Fwd: Should I be able to Merge content when Synchronizing

[Christian Halstrick <christian.halstrick@xxxxxxxxx>]

> This is _exactly_ my problem.
>
> If there are only differences in the incoming version then there is
> effectively no merge required so a replacement of the current with
> the incoming is appropriate.
>
> If there is any sort of difference between the current and incoming
> then there may be no textual conflict, but there is a 'model' conflict
> that I want to resolve through my comparator.

I guess I know what you mean but what you wrote is not so clear. Let
me summarize what JGit will do during a merge with the default merge
strategy "resolve":

1. imagine you have checked out commit <a> and you are trying to merge
with commit <b>
2. jgit will look at the revision graph and find out the common
predecessor <base> between <a> and <b>
3. jgit will now iterate over every file f found in <a> or <b> or
<base> and compares the content of the file in the three states
4a. content(f, a)=content(f, b) (both commits have the same content)
-> no conflict, content(f, a) will remain to be content for the file
4b. content(f, base)=content(f, b) (nothing was changed in b) -> no
conflict, content(f, a) will remain to be content for the file
4c. content(f, base)=content(f, a) (nothing was changed in a) -> no
conflict, content(f, b) will become new content for the file
4d. else (all three contents differ) -> try a three-way-merge. If that
merge succeeds -> no conflict,
      if If that merge does not succeed -> conflict, put the three
contents into the index (stage 1,2,3) and put the merge result
      (with conflict markers) into the workingtree file

There is also a merge strategy "SimpleTwoWayInCore" in which is
similar to "resolve" but where 4d is different
4d'. else (all three contents differ) -> always report a conflict, put
the three contents into the index (stage 1,2,3)
That sounds much like what you want, right. Problem: The merge
operation is done with the same algorithm for all files.
Is that's a problem for you, or are all your files of that kind that
you want your special merge-driver? Another problem:
From EGit you currently cannot choose the merge strategy. But we could
add such an option to the repository configuration
so you can choose for the merge algorithm which should be used.

Ciao
  Chris