replay: use standard revision ranges

Instead of the fixed "<oldbase> <branch>" arguments, the replay
command now accepts "<revision-range>..." arguments in a similar
way as many other Git commands. This makes its interface more
standard and more flexible.

This also enables many revision related options accepted and
eaten by setup_revisions(). If the replay command was a high level
one or had a high level mode, it would make sense to restrict some
of the possible options, like those generating non-contiguous
history, as they could be confusing for most users.

Also as the interface of the command is now mostly finalized,
we can add more documentation and more testcases to make sure
the command will continue to work as designed in the future.

We only document the rev-list related options among all the
revision related options that are now accepted, as the rev-list
related ones are probably the most useful for now.

Helped-by: Dragan Simic <dsimic@manjaro.org>
Helped-by: Linus Arver <linusa@google.com>
Co-authored-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 54 insertions, 4 deletions

diff --git a/Documentation/git-replay.txt b/Documentation/git-replay.txt
index 267282d92a..f7b232caa2 100644
--- a/Documentation/git-replay.txt
+++ b/Documentation/git-replay.txt
@@ -9,16 +9,16 @@ git-replay - EXPERIMENTAL: Replay commits on a new base, works with bare repos t
 SYNOPSIS
 --------
 [verse]
-(EXPERIMENTAL!) 'git replay' --onto <newbase> <oldbase> <branch>
+(EXPERIMENTAL!) 'git replay' --onto <newbase> <revision-range>...
 
 DESCRIPTION
 -----------
 
-Takes a range of commits, specified by <oldbase> and <branch>, and
-replays them onto a new location (see `--onto` option below). Leaves
+Takes ranges of commits and replays them onto a new location. Leaves
 the working tree and the index untouched, and updates no references.
 The output of this command is meant to be used as input to
-`git update-ref --stdin`, which would update the relevant branches.
+`git update-ref --stdin`, which would update the relevant branches
+(see the OUTPUT section below).
 
 THIS COMMAND IS EXPERIMENTAL. THE BEHAVIOR MAY CHANGE.
 
@@ -28,6 +28,30 @@ OPTIONS
 --onto <newbase>::
 	Starting point at which to create the new commits.  May be any
 	valid commit, and not just an existing branch name.
++
+The update-ref command(s) in the output will update the branch(es) in
+the revision range to point at the new commits, similar to the way how
+`git rebase --update-refs` updates multiple branches in the affected
+range.
+
+<revision-range>::
+	Range of commits to replay; see "Specifying Ranges" in
+	linkgit:git-rev-parse and the "Commit Limiting" options below.
+
+include::rev-list-options.txt[]
+
+OUTPUT
+------
+
+When there are no conflicts, the output of this command is usable as
+input to `git update-ref --stdin`.  It is of the form:
+
+	update refs/heads/branch1 ${NEW_branch1_HASH} ${OLD_branch1_HASH}
+	update refs/heads/branch2 ${NEW_branch2_HASH} ${OLD_branch2_HASH}
+	update refs/heads/branch3 ${NEW_branch3_HASH} ${OLD_branch3_HASH}
+
+where the number of refs updated depends on the arguments passed and
+the shape of the history being replayed.
 
 EXIT STATUS
 -----------
@@ -37,6 +61,32 @@ the replay has conflicts, the exit status is 1.  If the replay is not
 able to complete (or start) due to some kind of error, the exit status
 is something other than 0 or 1.
 
+EXAMPLES
+--------
+
+To simply rebase `mybranch` onto `target`:
+
+------------
+$ git replay --onto target origin/main..mybranch
+update refs/heads/mybranch ${NEW_mybranch_HASH} ${OLD_mybranch_HASH}
+------------
+
+When calling `git replay`, one does not need to specify a range of
+commits to replay using the syntax `A..B`; any range expression will
+do:
+
+------------
+$ git replay --onto origin/main ^base branch1 branch2 branch3
+update refs/heads/branch1 ${NEW_branch1_HASH} ${OLD_branch1_HASH}
+update refs/heads/branch2 ${NEW_branch2_HASH} ${OLD_branch2_HASH}
+update refs/heads/branch3 ${NEW_branch3_HASH} ${OLD_branch3_HASH}
+------------
+
+This will simultaneously rebase `branch1`, `branch2`, and `branch3`,
+all commits they have since `base`, playing them on top of
+`origin/main`. These three branches may have commits on top of `base`
+that they have in common, but that does not need to be the case.
+
 GIT
 ---
 Part of the linkgit:git[1] suite