This implements a building block of "signed-off-by line" #1399 and "commit
--verbose" #1946. We'll probably need an easy way to customize the diff part,
but I'm not sure if it can be as simple as a template alias function. User
might want to embed diffs without "JJ: " prefixes?
Perhaps, we can deprecate "ui.default-description", but it's not addressed in
this patch. It could be replaced with "default_description" template alias,
but we might want to configure default per command. Suppose we add a default
"backout_description" template, it would have to be rendered against the
source commit, not the newly-created backout commit.
The template key is named as "draft_commit_description" because it is the
template to generate an editor template. "templates.commit_description_template"
sounds a bit odd.
There's one minor behavior change: the default description is now terminated
by "\n".
Closes#1354
This could be handled by description_template_for_describe(), but I think it's
better to do mutation by caller. I also think commands like "backout" or "new"
can do a similar thing to generate a default commit description from the source
or merge parent commits.
This will help consolidate description_template_for_*() functions and port them
to templater. This change also means the committer (and operation start)
timestamp is set earlier. I think that's good.
This function doesn't actually need commits, it only needs their IDs. In some
contexts we may only have commit IDs, so there's no need to require an iterator
of Commits.
This commit also adds a `CommitIteratorExt` that makes it easy to convert an
iterator of `&Commit` to an iterator of `&CommitId`.
I'm going to add a prefix resolution method to OpStore, but OpStore is
unrelated to the index. I think ObjectId, HexPrefix, and PrefixResolution can
be extracted to this module.
It seems better to have the caller pass the transaction description
when we finish the transaction than when we start it. That way we have
all the information we want to include more readily available.
Renamed `description_template_for_commit` to
`description_template_for_describe` since it's only used in
`cmd_describe`.
Renamed `description_template_for_cmd_split` to
`description_template_for_commit` and modified to accomodate empty
`intro` argument.
Fixes#2439.
