On Fri, Feb 25, 2022 at 7:07 PM Junio C Hamano [off-list ref] wrote:

* en/merge-tree (2022-02-23) 13 commits
 - git-merge-tree.txt: add a section on potentional usage mistakes
 - merge-tree: add a --allow-unrelated-histories flag
 - merge-tree: allow `ls-files -u` style info to be NUL terminated
 - merge-tree: provide easy access to `ls-files -u` style info
 - merge-tree: provide a list of which files have conflicts
 - merge-ort: provide a merge_get_conflicted_files() helper function
 - merge-tree: support including merge messages in output
 - merge-ort: split out a separate display_update_messages() function
 - merge-tree: implement real merges
 - merge-tree: add option parsing and initial shell for real merge function
 - merge-tree: move logic for existing merge into new function
 - merge-tree: rename merge_trees() to trivial_merge_trees()
 - Merge branch 'en/remerge-diff' into en/merge-trees

 A new command is introduced that takes two commits and computes a
 tree that would be contained in the resulting merge commit, if the
 histories leading to these two commits were to be merged, and is
 added as a new mode of "git merge-tree" subcommand.

 Will merge to 'next'.
 source: [ref]

Let's wait.  The extra data needed to handle Dscho's usecase might
still suggest an output format change, and the command is intended to
be plumbing-ish, so I'd like a bit more time to make sure we've got
the format we want.  Also, his comment/suggestion about -z affecting
"Informational Messages" section is also interesting and might be
worth doing even if it doesn't provide all the things Dscho wants for
his usecase.