Commit Graph

6 Commits

Author SHA1 Message Date
Elijah Newren
7976721d17 merge-tree: add a --allow-unrelated-histories flag
Folks may want to merge histories that have no common ancestry; provide
a flag with the same name as used by `git merge` to allow this.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-06-22 16:10:06 -07:00
Elijah Newren
7c48b27822 merge-tree: allow ls-files -u style info to be NUL terminated
Much as `git ls-files` has a -z option, let's add one to merge-tree so
that the conflict-info section can be NUL terminated (and avoid quoting
of unusual filenames).

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-06-22 16:10:06 -07:00
Elijah Newren
b520bc6caa merge-tree: provide easy access to ls-files -u style info
Much like `git merge` updates the index with information of the form
    (mode, oid, stage, name)
provide this output for conflicted files for merge-tree as well.
Provide a --name-only option for users to exclude the mode, oid, and
stage and only get the list of conflicted filenames.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-06-22 16:10:06 -07:00
Elijah Newren
7fa3338870 merge-tree: provide a list of which files have conflicts
Callers of `git merge-tree --write-tree` will often want to know which
files had conflicts.  While they could potentially attempt to parse the
CONFLICT notices printed, those messages are not meant to be machine
readable.  Provide a simpler mechanism of just printing the files (in
the same format as `git ls-files` with quoting, but restricted to
unmerged files) in the output before the free-form messages.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-06-22 16:10:06 -07:00
Elijah Newren
a1a7811975 merge-tree: support including merge messages in output
When running `git merge-tree --write-tree`, we previously would only
return an exit status reflecting the cleanness of a merge, and print out
the toplevel tree of the resulting merge.  Merges also have
informational messages, such as:
  * "Auto-merging <PATH>"
  * "CONFLICT (content): ..."
  * "CONFLICT (file/directory)"
  * etc.
In fact, when non-content conflicts occur (such as file/directory,
modify/delete, add/add with differing modes, rename/rename (1to2),
etc.), these informational messages may be the only notification the
user gets since these conflicts are not representable in the contents
of the file.

Add a --[no-]messages option so that callers can request these messages
be included at the end of the output.  Include such messages by default
when there are conflicts, and omit them by default when the merge is
clean.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-06-22 16:10:06 -07:00
Elijah Newren
1f0c3a29da merge-tree: implement real merges
This adds the ability to perform real merges rather than just trivial
merges (meaning handling three way content merges, recursive ancestor
consolidation, renames, proper directory/file conflict handling, and so
forth).  However, unlike `git merge`, the working tree and index are
left alone and no branch is updated.

The only output is:
  - the toplevel resulting tree printed on stdout
  - exit status of 0 (clean), 1 (conflicts present), anything else
    (merge could not be performed; unknown if clean or conflicted)

This output is meant to be used by some higher level script, perhaps in
a sequence of steps like this:

   NEWTREE=$(git merge-tree --write-tree $BRANCH1 $BRANCH2)
   test $? -eq 0 || die "There were conflicts..."
   NEWCOMMIT=$(git commit-tree $NEWTREE -p $BRANCH1 -p $BRANCH2)
   git update-ref $BRANCH1 $NEWCOMMIT

Note that higher level scripts may also want to access the
conflict/warning messages normally output during a merge, or have quick
access to a list of files with conflicts.  That is not available in this
preliminary implementation, but subsequent commits will add that
ability (meaning that NEWTREE would be a lot more than a tree in the
case of conflicts).

This also marks the traditional trivial merge of merge-tree as
deprecated.  The trivial merge not only had limited applicability, the
output format was also difficult to work with (and its format
undocumented), and will generally be less performant than real merges.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-06-22 16:10:05 -07:00