Re: [PATCH 2/3] make union merge an xdl merge favor

Junio C Hamano <gitster@pobox.com> writes:

Actually I take the first sentence back. The --union option given to merge-file is comparable to --ours/--theirs that let you (a Porcelain writer using the command) access the ll-merge machinery to resolve conflicts in favor of one side on contents stored in an arbitrary temporary filename (or even outside a git repository). So as a feature I think addition of "union" is in line with what we already have.

But I at the same time I think that we could add the feature while making existing --ours/--theirs options redundant (and deprecatable if we want to in the longer term), if the attributes mechanism is made available to us (e.g. add "--attribute-path=<use attributes for this path>" option, and/or perhaps add "--attributes=<use this set of attributes>" option) directly from the command line.

I doubt "checkout --union" is a good idea, though. Its --ours/--theirs options do not have anything to do with merge (it specifies _what_ to checkout, not _how_), and the comparison I made in the previous paragraph for merge-file does not apply.

It however is plausible that in a scenario where:

 (1) you ran "git merge" (or anything that results in conflicts) and got a
     conflict; and

 (2) you know using other ll-merge backend, perhaps a custom one you have
     that is accessible via ll-merge, would have produced a better result.

it might be useful if you can say "forget this failed auto-merge; attempt the same merge for the path but using this different ll-merge backend". I don't think that feature belongs to "checkout", though.