format-rev: introduce builtin for on-demand pretty formatting

2026-05-12T00:09:51Z

Introduce a new builtin for pretty formatting one revision expression per line or commit object names found in running text. Sometimes you want to format commits. Most of the time you’re walking the graph, e.g. getting a range of commits like `master..topic`. That’s a job for git-log(1). But there are times when you want to format commits that you encounter on demand: • Full hashes in running text that you might want to pretty-print • git-last-modified(1) outputs full hashes that you can do the same with • git-cherry(1) has `-v` for commit subject, but maybe you want something else? But now you can’t use git-log(1), git-show(1), or git-rev-list(1): • You can’t feed commits piecemeal to these commands, one input for one output; they block until standard in is closed • You can’t feed a list of possibly duplicate commits, like the output of git-last-modified(1); they effectively deduplicate the output Beyond these two points there’s also the input massage problem: you cannot feed mixed input (revisions mixed with arbitrary text). One might hope that git-cat-file(1) can save us. But it doesn’t support pretty formats. But there is one command that already both handles revisions as arguments, revisions on standard input, and even revisions mixed in with arbitrary text. Namely git-name-rev(1): the command for outputting symbolic names for commits. We made some room in `builtin/name-rev.c` two commits ago. Let’s now add this new git-format-rev(1) command. Taking inspiration from git-name-rev(1), there are two modes: • revs: like git-name-rev(1) in argv mode, but one revision per line on standard in • text: like git-name-rev(1) with `--annotate-stdin` *** We need to add this command to the exception list in `t/t1517-outside-repo.sh` because it uses “EXPERIMENTAL!” in the usage line. Helped-by: Phillip Wood Helped-by: Ramsay Jones Helped-by: Junio C Hamano Signed-off-by: Kristoffer Haugsbakk Signed-off-by: Junio C Hamano

git/Documentation/git-format-rev.adoc, branch jch

format-rev: introduce builtin for on-demand pretty formatting