The experimental 'git history' command has been taught a new 'drop'
subcommand to remove a commit, with its descendants replayed onto its
parent.
* ps/history-drop:
builtin/history: implement "drop" subcommand
builtin/history: split handling of ref updates into two phases
replay: expose `replay_result_queue_update()`
reset: stop assuming that the caller passes in a clean index
reset: allow the caller to specify the current HEAD object
reset: introduce ability to skip updating HEAD
reset: introduce dry-run mode
reset: modernize flags passed to `reset_working_tree()`
reset: rename `reset_head()`
reset: drop `USE_THE_REPOSITORY_VARIABLE`
read-cache: split out function to drop unmerged entries to stage 0
A write file stream resource leak has been fixed as part of a code
cleanup.
* jc/history-message-prep-fix:
history: streamline message preparation and plug file stream leak
A common operation when editing the commit history is to drop a specific
commit from the history entirely, but this operation is not currently
covered by git-history(1).
A couple of noteworthy bits:
- This is the first git-history(1) command that will ultimately result
in changes to both the index and the working tree. We thus have to
add logic to merge resulting changes into those.
- It is still not possible to replay merge commits, so this limitation
is inherited for the new "drop" command.
- For now we refuse to drop root commits. While we _can_ indeed drop
root commits in the general case, there are edge cases where the
resulting history would become completely empty. This is thus left
to a subsequent patch series.
Other than that, most of the logic is rather straight-forward as we can
continue to build on the preexisting logic in git-history(1) for most of
the part.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The function `handle_reference_updates()` is used by git-history(1) to
update all references that refer to commits that have been rewritten. As
such, it performs two steps:
- It gathers the references that need to be updated in the first
place.
- It prepares and commits the reference transaction.
In a subsequent commit we'll want to handle those two steps separately.
Prepare for this by splitting up the function into two.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
An early part of fill_commit_message() function uses write_file_buf()
to write out what was prepared in a strbuf, which is primarily meant
for use by callers that have their own message prepared fully and
called as the last thing to flush it to the destination file.
However, the function then opens a file stream in append mode to
further write into it. It may have been understandable if this was
a later addition, but it seems it came from a single commit,
d205234c (builtin/history: implement "reword" subcommand,
2026-01-13), which is somewhat puzzling, but anyway...
Just open the file stream upfront for writing, write the message
the function has in the strbuf, and then keep writing whatever it
wants to write to the same open file stream.
And do not forget to close the stream. We are about to pass the
resulting file to an external editor, and on some systems, notably
Windows, you are not supposed to keep a file open while expecting
another program to access it.
Diagnosed-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Refactor `is_bare_repository()` to take in a repository parameter so
that we no longer depend on `the_repository`. Adjust callers
accordingly.
Furthermore, move the function outside of the declarations that are only
available when `USE_THE_REPOSITORY_VARIABLE` is set, as it no longer
depends on that variable.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Replace `free_commit_list` with `commit_list_free`. The former was
deprecated in 9f18d089 (commit: rename `free_commit_list()` to conform
to coding guidelines, 2026-01-15).
This allows us to remove all the deprecated functions in the
next commit:
• `copy_commit_list`
• `reverse_commit_list`
• `free_commit_list`
Acked-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Kristoffer Haugsbakk <code@khaugsbakk.name>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The newly introduced git-history(1) command provides functionality to
easily edit commit history while also rebasing dependent branches. The
functionality exposed by this command is still somewhat limited though.
One common use case when editing commit history that is not yet covered
is fixing up a specific commit. Introduce a new subcommand that allows
the user to do exactly that by performing a three-way merge into the
target's commit tree, using HEAD's tree as the merge base. The flow is
thus essentially:
$ echo changes >file
$ git add file
$ git history fixup HEAD~
Like with the other commands, this will automatically rebase dependent
branches, as well. Unlike the other commands though:
- The command does not work in a bare repository as it interacts with
the index.
- The command may run into merge conflicts. If so, the command will
simply abort.
Especially the second item limits the usefulness of this command a bit.
But there are plans to introduce first-class conflicts into Git, which
will help use cases like this one.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The function `commit_tree_with_edited_message_ext()` can be used to
commit a tree with a specific list of parents with an edited commit
message. This function is useful outside of editing the commit message
though, as it also performs the plumbing to extract the original commit
message and strip some headers from it.
Refactor the function to receive a flags field that allows the caller to
control whether or not the commit message should be edited, or whether
it should be retained as-is. This will be used in a subsequent commit.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
"print" is not a valid argument for --update-refs. List both valid
alternatives literally in the argh string, consistent with documentation
and usage string.
Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
"git history" learned the "split" subcommand.
* ps/history-split:
builtin/history: implement "split" subcommand
builtin/history: split out extended function to create commits
cache-tree: allow writing in-memory index as tree
add-patch: allow disabling editing of hunks
add-patch: add support for in-memory index patching
add-patch: remove dependency on "add-interactive" subsystem
add-patch: split out `struct interactive_options`
add-patch: split out header from "add-interactive.h"
git history reword expects a single valid revision argument and errors
out if it doesn't get it. In that case the struct rev_info passed to
release_revisions() for cleanup is still uninitialized, which can result
in attempts to free(3) random pointers. Avoid that by initializing the
structure.
Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
It is quite a common use case that one wants to split up one commit into
multiple commits by moving parts of the changes of the original commit
out into a separate commit. This is quite an involved operation though:
1. Identify the commit in question that is to be dropped.
2. Perform an interactive rebase on top of that commit's parent.
3. Modify the instruction sheet to "edit" the commit that is to be
split up.
4. Drop the commit via "git reset HEAD~".
5. Stage changes that should go into the first commit and commit it.
6. Stage changes that should go into the second commit and commit it.
7. Finalize the rebase.
This is quite complex, and overall I would claim that most people who
are not experts in Git would struggle with this flow.
Introduce a new "split" subcommand for git-history(1) to make this way
easier. All the user needs to do is to say `git history split $COMMIT`.
From hereon, Git asks the user which parts of the commit shall be moved
out into a separate commit and, once done, asks the user for the commit
message. Git then creates that split-out commit and applies the original
commit on top of it.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In the next commit we're about to introduce a new command that splits up
a commit into two. Most of the logic will be shared with rewording
commits, except that we also need to have control over the parents and
the old/new trees.
Extract a new function `commit_tree_with_edited_message_ext()` to
prepare for this commit.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
With the preceding commit we have changed "--ref-action=" to only
control which refs are supposed to be updated, not what happens with
them. As a consequence, the option is now somewhat misnamed, as we don't
control the action itself anymore.
Rename it to "--update-refs=" to better align it with its new use.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The git-history(1) command has the ability to perform a dry-run
that will not end up modifying any references. Instead, we'll only print
any ref updates that would happen as a consequence of performing the
operation.
This mode is somewhat hidden though behind the "--ref-action=print"
option. This command line option has its origin in git-replay(1), where
it's probably an okayish interface as this command is sitting more on
the plumbing side of tools. But git-history(1) is a user-facing tool,
and this way of achieving a dry-run is way too technical and thus not
very discoverable.
Besides usability issues, it also has another issue: the dry-run mode
will always operate as if the user wanted to rewrite all branches. But
in fact, the user also has the option to only update the HEAD reference,
and they might want to perform a dry-run of such an operation, too. We
could of course introduce "--ref-action=print-head", but that would
become even less ergonomic.
Replace "--ref-action=print" with a new "--dry-run" toggle. This new
toggle works with both "--ref-action={head,branches}" and is way more
discoverable.
Add a test to verify that both "--ref-action=" values behave as
expected.
This patch is best viewed with "--ignore-space-change".
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The replay infrastructure is not yet capable of replaying merge commits.
Unfortunately, we only notice that we're about to replay merges after we
have already asked the user for input, so any commit message that the
user may have written will be discarded in that case.
Fix this by checking whether the revwalk contains merge commits before
we ask for user input.
Adapt one of the tests that is expected to fail because of this check
to use false(1) as editor. If the editor had been executed by Git, it
would fail with the error message "Aborting commit as launching the
editor failed."
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When setting up the revision walk in git-history(1) we also perform some
verifications whether the request actually looks sane. Unfortunately,
these verifications come _after_ we have already asked the user for the
commit message of the commit that is to be rewritten. So in case any of
the verifications fails, the user will have lost their modifications.
Extract the function to set up the revision walk and call it before we
ask for user input to fix this.
Adapt one of the tests that is expected to fail because of this check
to use false(1) as editor. If the editor had been executed by Git, it
would fail with the error message "Aborting commit as launching the
editor failed."
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Implement a new "reword" subcommand for git-history(1). This subcommand
is similar to the user performing an interactive rebase with a single
commit changed to use the "reword" instruction.
The "reword" subcommand is built on top of the replay subsystem
instead of the sequencer. This leads to some major differences compared
to git-rebase(1):
- We do not check out the commit that is to be reworded and instead
perform the operation in-memory. This has the obvious benefit of
being significantly faster compared to git-rebase(1), but even more
importantly it allows the user to rewrite history even if there are
local changes in the working tree or in the index.
- We do not execute any hooks, even though we leave some room for
changing this in the future.
- By default, all local branches that contain the commit will be
rewritten. This especially helps with workflows that use stacked
branches.
Helped-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When rewriting history via git-rebase(1) there are a few very common use
cases:
- The ordering of two commits should be reversed.
- A commit should be split up into two commits.
- A commit should be dropped from the history completely.
- Multiple commits should be squashed into one.
- Editing an existing commit that is not the tip of the current
branch.
While these operations are all doable, it often feels needlessly kludgey
to do so by doing an interactive rebase, using the editor to say what
one wants, and then perform the actions. Also, some operations like
splitting up a commit into two are way more involved than that and
require a whole series of commands.
Rebases also do not update dependent branches. The use of stacked
branches has grown quite common with competing version control systems
like Jujutsu though, so it clearly is a need that users have. While
rebases _can_ serve this use case if one always works on the latest
stacked branch, it is somewhat awkward and very easy to get wrong.
Add a new "history" command to plug these gaps. This command will have
several different subcommands to imperatively rewrite history for common
use cases like the above.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Junio C Hamano