1
0
Fork 0
mirror of https://github.com/git/git.git synced 2024-05-11 14:46:08 +02:00
Commit Graph

241 Commits

Author SHA1 Message Date
Charvi Mendiratta 00ea64ed7a doc/git-commit: add documentation for fixup=[amend|reword] options
Mentored-by: Christian Couder <chriscool@tuxfamily.org>
Mentored-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Helped-by: Eric Sunshine <sunshine@sunshineco.com>
Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Charvi Mendiratta <charvi077@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-03-15 14:29:36 -07:00
Charvi Mendiratta fa153c1cd7 doc/rebase -i: fix typo in the documentation of 'fixup' command
Mentored-by: Christian Couder <chriscool@tuxfamily.org>
Mentored-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Helped-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Charvi Mendiratta <charvi077@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-02-10 13:58:19 -08:00
Charvi Mendiratta 2c0aa2ce2e doc/git-rebase: add documentation for fixup [-C|-c] options
Mentored-by: Christian Couder <chriscool@tuxfamily.org>
Mentored-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Reviewed-by: Marc Branchaud <marcnarc@xiplink.com>
Signed-off-by: Charvi Mendiratta <charvi077@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-01-29 15:21:56 -08:00
Bradley M. Kuhn 3abd4a67d9 Documentation: stylistically normalize references to Signed-off-by:
Ted reported an old typo in the git-commit.txt and merge-options.txt.
Namely, the phrase "Signed-off-by line" was used without either a
definite nor indefinite article.

Upon examination, it seems that the documentation (including items in
Documentation/, but also option help strings) have been quite
inconsistent on usage when referring to `Signed-off-by`.

First, very few places used a definite or indefinite article with the
phrase "Signed-off-by line", but that was the initial typo that led
to this investigation.  So, normalize using either an indefinite or
definite article consistently.

The original phrasing, in Commit 3f971fc425 (Documentation updates,
2005-08-14), is "Add Signed-off-by line".  Commit 6f855371a5 (Add
--signoff, --check, and long option-names. 2005-12-09) switched to
using "Add `Signed-off-by:` line", but didn't normalize the former
commit to match.  Later commits seem to have cut and pasted from one
or the other, which is likely how the usage became so inconsistent.

Junio stated on the git mailing list in
<xmqqy2k1dfoh.fsf@gitster.c.googlers.com> a preference to leave off
the colon.  Thus, prefer `Signed-off-by` (with backticks) for the
documentation files and Signed-off-by (without backticks) for option
help strings.

Additionally, Junio argued that "trailer" is now the standard term to
refer to `Signed-off-by`, saying that "becomes plenty clear that we
are not talking about any random line in the log message".  As such,
prefer "trailer" over "line" anywhere the former word fits.

However, leave alone those few places in documentation that use
Signed-off-by to refer to the process (rather than the specific
trailer), or in places where mail headers are generally discussed in
comparison with Signed-off-by.

Reported-by: "Theodore Y. Ts'o" <tytso@mit.edu>
Signed-off-by: Bradley M. Kuhn <bkuhn@sfconservancy.org>
Acked-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-10-20 11:57:40 -07:00
Junio C Hamano ed9d8331d2 Merge branch 'pb/doc-sequence-editor-configuration'
Doc update.

* pb/doc-sequence-editor-configuration:
  doc: mention GIT_SEQUENCE_EDITOR and 'sequence.editor' more
2020-09-03 12:37:06 -07:00
Junio C Hamano 9c31b19dd0 Merge branch 'pw/rebase-i-more-options'
"git rebase -i" learns a bit more options.

* pw/rebase-i-more-options:
  t3436: do not run git-merge-recursive in dashed form
  rebase: add --reset-author-date
  rebase -i: support --ignore-date
  rebase -i: support --committer-date-is-author-date
  am: stop exporting GIT_COMMITTER_DATE
  rebase -i: add --ignore-whitespace flag
2020-09-03 12:37:01 -07:00
Philippe Blain 902a126eca doc: mention GIT_SEQUENCE_EDITOR and 'sequence.editor' more
The environment variable `GIT_SEQUENCE_EDITOR`, and the configuration
variable 'sequence.editor', which were added in 821881d88d ("rebase -i":
support special-purpose editor to edit insn sheet, 2011-10-17), are
mentioned in the `git config` man page but not anywhere else.

Include `config/sequencer.txt` in `git-rebase.txt`, so that both the
environment variable and the configuration setting are mentioned there.

Also, add `GIT_SEQUENCE_EDITOR` to the list of environment variables
in `git(1)`.

Signed-off-by: Philippe Blain <levraiphilippeblain@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-08-31 11:45:05 -07:00
Rohit Ashiwal 27126692ba rebase: add --reset-author-date
The previous commit introduced --ignore-date flag to rebase -i, but the
name is rather vague as it does not say whether the author date or the
committer date is ignored. Add an alias to convey the precise purpose.

Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Rohit Ashiwal <rohit.ashiwal265@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-08-19 15:22:56 -07:00
Phillip Wood a3894aad67 rebase -i: support --ignore-date
Rebase is implemented with two different backends - 'apply' and
'merge' each of which support a different set of options. In
particular the apply backend supports a number of options implemented
by 'git am' that are not implemented in the merge backend. This means
that the available options are different depending on which backend is
used which is confusing. This patch adds support for the --ignore-date
option to the merge backend. This option uses the current time as the
author date rather than reusing the original author date when
rewriting commits. We take care to handle the combination of
--ignore-date and --committer-date-is-author-date in the same way as
the apply backend.

Original-patch-by: Rohit Ashiwal <rohit.ashiwal265@gmail.com>
Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-08-19 15:19:59 -07:00
Phillip Wood 7573cec52c rebase -i: support --committer-date-is-author-date
Rebase is implemented with two different backends - 'apply' and
'merge' each of which support a different set of options. In
particular the apply backend supports a number of options implemented
by 'git am' that are not implemented in the merge backend. This means
that the available options are different depending on which backend is
used which is confusing. This patch adds support for the
--committer-date-is-author-date option to the merge backend. This
option uses the author date of the commit that is being rewritten as
the committer date when the new commit is created.

Original-patch-by: Rohit Ashiwal <rohit.ashiwal265@gmail.com>
Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-08-17 11:58:37 -07:00
Rohit Ashiwal ef484add9f rebase -i: add --ignore-whitespace flag
Rebase is implemented with two different backends - 'apply' and
'merge' each of which support a different set of options. In
particular the apply backend supports a number of options implemented
by 'git am' that are not implemented in the merge backend. This means
that the available options are different depending on which backend is
used which is confusing. This patch adds support for the
--ignore-whitespace option to the merge backend. This option treats
lines with only whitespace changes as unchanged and is implemented in
the merge backend by translating it to -Xignore-space-change.

Signed-off-by: Rohit Ashiwal <rohit.ashiwal265@gmail.com>
Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-07-13 07:55:37 -07:00
Junio C Hamano 3ed0f1e3a1 Merge branch 'ma/rebase-doc-typofix' into master
Typofix.

* ma/rebase-doc-typofix:
  git-rebase.txt: fix description list separator
2020-07-09 14:00:45 -07:00
Martin Ågren 81de0c01cf git-rebase.txt: fix description list separator
We don't give a "::" for the list separator, but just a single ":". This
ends up rendering literally, "--apply: Use applying strategies ...". As
a follow-on error, the list continuation, "+", also ends up rendering
literally (because we don't have a list).

This was introduced in 52eb738d6b ("rebase: add an --am option",
2020-02-15) and survived the rename in 10cdb9f38a ("rebase: rename the
two primary rebase backends", 2020-02-15).

Signed-off-by: Martin Ågren <martin.agren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-07-09 11:35:57 -07:00
Denton Liu c5e786abe3 Doc: reference the "stash list" in autostash docs
In documentation pertaining to autostash behavior, we refer to the
"stash reflog". This description is too low-level as the reflog refers
to an implementation detail of how the stash works and, for end-users,
they do not need to be aware of this at all.

Change references of "stash reflog" to "stash list", which should
provide more accessible terminology for end-users.

Signed-off-by: Denton Liu <liu.denton@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-05-05 16:07:30 -07:00
Junio C Hamano 6d6b412da3 Merge branch 'en/rebase-root-and-fork-point-are-incompatible'
Incompatible options "--root" and "--fork-point" of "git rebase"
have been marked and documented as being incompatible.

* en/rebase-root-and-fork-point-are-incompatible:
  rebase: display an error if --root and --fork-point are both provided
2020-05-01 13:39:58 -07:00
Junio C Hamano 3afdeef33e Merge branch 'dl/merge-autostash-rebase-quit-fix'
The stash entry created by "git rebase --autosquash" to keep the
initial dirty state were discarded by mistake upon "git rebase
--quit", which has been corrected.

* dl/merge-autostash-rebase-quit-fix:
  rebase: save autostash entry into stash reflog on --quit
2020-04-29 16:15:27 -07:00
Junio C Hamano 1779d181b5 Merge branch 'en/rebase-doc-hooks-called-by-accident'
"git rebase" happens to call some hooks meant for "checkout" and
"commit" by this was not a designed behaviour than historical
accident.  This has been documented.

* en/rebase-doc-hooks-called-by-accident:
  git-rebase.txt: add another hook to the hooks section, and explain more
2020-04-28 15:49:56 -07:00
Denton Liu 9b2df3e8d0 rebase: save autostash entry into stash reflog on --quit
In a03b55530a (merge: teach --autostash option, 2020-04-07), the
--autostash option was introduced for `git merge`. Notably, when
`git merge --quit` is run with an autostash entry present, it is saved
into the stash reflog. This is contrasted with the current behaviour of
`git rebase --quit` where the autostash entry is simply just dropped out
of existence.

Adopt the behaviour of `git merge --quit` in `git rebase --quit` and
save the autostash entry into the stash reflog instead of just deleting
it.

Signed-off-by: Denton Liu <liu.denton@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-28 12:35:38 -07:00
Elijah Newren a35413c378 rebase: display an error if --root and --fork-point are both provided
--root implies we want to rebase all commits since the beginning of
history.  --fork-point means we want to use the reflog of the specified
upstream to find the best common ancestor between <upstream> and
<branch> and only rebase commits since that common ancestor.  These
options are clearly contradictory, so throw an error (instead of
segfaulting on a NULL pointer) if both are specified.

Reported-by: Alexander Berg <alexander.berg@atos.net>
Documentation-by: Alban Gruin <alban.gruin@gmail.com>
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-27 11:51:26 -07:00
Junio C Hamano d6d561db1c Merge branch 'jt/rebase-allow-duplicate'
Allow "git rebase" to reapply all local commits, even if the may be
already in the upstream, without checking first.

* jt/rebase-allow-duplicate:
  rebase --merge: optionally skip upstreamed commits
2020-04-22 13:43:00 -07:00
Junio C Hamano c7d8f69da5 Merge branch 'en/rebase-no-keep-empty'
"git rebase" (again) learns to honor "--no-keep-empty", which lets
the user to discard commits that are empty from the beginning (as
opposed to the ones that become empty because of rebasing).  The
interactive rebase also marks commits that are empty in the todo.

* en/rebase-no-keep-empty:
  rebase: fix an incompatible-options error message
  rebase: reinstate --no-keep-empty
  rebase -i: mark commits that begin empty in todo editor
2020-04-22 13:43:00 -07:00
Junio C Hamano fc3f6fd7be Merge branch 'dd/no-gpg-sign'
"git rebase" learned the "--no-gpg-sign" option to countermand
commit.gpgSign the user may have.

* dd/no-gpg-sign:
  Documentation: document merge option --no-gpg-sign
  Documentation: merge commit-tree --[no-]gpg-sign
  Documentation: reword commit --no-gpg-sign
  Documentation: document am --no-gpg-sign
  cherry-pick/revert: honour --no-gpg-sign in all case
  rebase.c: honour --no-gpg-sign
2020-04-22 13:42:53 -07:00
Junio C Hamano d0eb895058 Merge branch 'pb/rebase-doc-typofix'
Typofix.

* pb/rebase-doc-typofix:
  git-rebase.txt: fix typo
2020-04-22 13:42:44 -07:00
Jonathan Tan 0fcb4f6b62 rebase --merge: optionally skip upstreamed commits
When rebasing against an upstream that has had many commits since the
original branch was created:

 O -- O -- ... -- O -- O (upstream)
  \
   -- O (my-dev-branch)

it must read the contents of every novel upstream commit, in addition to
the tip of the upstream and the merge base, because "git rebase"
attempts to exclude commits that are duplicates of upstream ones. This
can be a significant performance hit, especially in a partial clone,
wherein a read of an object may end up being a fetch.

Add a flag to "git rebase" to allow suppression of this feature. This
flag only works when using the "merge" backend.

This flag changes the behavior of sequencer_make_script(), called from
do_interactive_rebase() <- run_rebase_interactive() <-
run_specific_rebase() <- cmd_rebase(). With this flag, limit_list()
(indirectly called from sequencer_make_script() through
prepare_revision_walk()) will no longer call cherry_pick_list(), and
thus PATCHSAME is no longer set. Refraining from setting PATCHSAME both
means that the intermediate commits in upstream are no longer read (as
shown by the test) and means that no PATCHSAME-caused skipping of
commits is done by sequencer_make_script(), either directly or through
make_script_with_merges().

Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-11 14:15:57 -07:00
Elijah Newren b9cbd2958f rebase: reinstate --no-keep-empty
Commit d48e5e21da ("rebase (interactive-backend): make --keep-empty the
default", 2020-02-15) turned --keep-empty (for keeping commits which
start empty) into the default.  The logic underpinning that commit was:

  1) 'git commit' errors out on the creation of empty commits without an
     override flag
  2) Once someone determines that the override is worthwhile, it's
     annoying and/or harmful to required them to take extra steps in
     order to keep such commits around (and to repeat such steps with
     every rebase).

While the logic on which the decision was made is sound, the result was
a bit of an overcorrection.  Instead of jumping to having --keep-empty
being the default, it jumped to making --keep-empty the only available
behavior.  There was a simple workaround, though, which was thought to
be good enough at the time.  People could still drop commits which
started empty the same way the could drop any commits: by firing up an
interactive rebase and picking out the commits they didn't want from the
list.  However, there are cases where external tools might create enough
empty commits that picking all of them out is painful.  As such, having
a flag to automatically remove start-empty commits may be beneficial.

Provide users a way to drop commits which start empty using a flag that
existed for years: --no-keep-empty.  Interpret --keep-empty as
countermanding any previous --no-keep-empty, but otherwise leaving
--keep-empty as the default.

This might lead to some slight weirdness since commands like
  git rebase --empty=drop --keep-empty
  git rebase --empty=keep --no-keep-empty
look really weird despite making perfect sense (the first will drop
commits which become empty, but keep commits that started empty; the
second will keep commits which become empty, but drop commits which
started empty).  However, --no-keep-empty was named years ago and we are
predominantly keeping it for backward compatibility; also we suspect it
will only be used rarely since folks already have a simple way to drop
commits they don't want with an interactive rebase.

Reported-by: Bryan Turner <bturner@atlassian.com>
Reported-by: Sami Boukortt <sami@boukortt.com>
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-11 14:15:52 -07:00
Elijah Newren 1b5735f75c rebase -i: mark commits that begin empty in todo editor
While many users who intentionally create empty commits do not want them
thrown away by a rebase, there are third-party tools that generate empty
commits that a user might not want.  In the past, users have used rebase
to get rid of such commits (a side-effect of the fact that the --apply
backend is not currently capable of keeping them).  While such users
could fire up an interactive rebase and just remove the lines
corresponding to empty commits, that might be difficult if the
third-party tool generates many of them.  Simplify this task for users
by marking such lines with a suffix of " # empty" in the todo list.

Suggested-by: Sami Boukortt <sami@boukortt.com>
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-11 14:15:49 -07:00
Elijah Newren f7139e7cc2 git-rebase.txt: add another hook to the hooks section, and explain more
For more discussion about these hooks, their history relative to rebase,
and logical consistency between different types of operations, see
  https://lore.kernel.org/git/CABPp-BG0bFKUage5cN_2yr2DkmS04W2Z9Pg5WcROqHznV3XBdw@mail.gmail.com/
and the links to some threads referenced therein.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-05 14:49:16 -07:00
Đoàn Trần Công Danh c241371c04 rebase.c: honour --no-gpg-sign
Signed-off-by: Đoàn Trần Công Danh <congdanhqx@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-03 11:37:22 -07:00
Philippe Blain 344420bf0f git-rebase.txt: fix typo
Signed-off-by: Philippe Blain <levraiphilippeblain@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-03-28 18:14:33 -07:00
Elijah Newren 120b1eb731 git-rebase.txt: highlight backend differences with commit rewording
As noted by Junio:
    Back when "git am" was written, it was not considered a bug that the
    "git am --resolved" option did not offer the user a chance to update
    the log message to match the adjustment of the code the user made,
    but honestly, I'd have to say that it is a bug in "git am" in that
    over time it wasn't adjusted to the new world order where we
    encourage users to describe what they did when the automation
    hiccuped by opening an editor.  These days, even when automation
    worked well (e.g. a clean auto-merge with "git merge"), we open an
    editor.  The world has changed, and so should the expectations.

Junio also suggested providing a workaround such as allowing --no-edit
together with git rebase --continue, but that should probably be done in
a patch after the git-2.26.0 release.  For now, just document the known
difference in the Behavioral Differences section.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-03-11 12:11:08 -07:00
Elijah Newren 10cdb9f38a rebase: rename the two primary rebase backends
Two related changes, with separate rationale for each:

Rename the 'interactive' backend to 'merge' because:
  * 'interactive' as a name caused confusion; this backend has been used
    for many kinds of non-interactive rebases, and will probably be used
    in the future for more non-interactive rebases than interactive ones
    given that we are making it the default.
  * 'interactive' is not the underlying strategy; merging is.
  * the directory where state is stored is not called
    .git/rebase-interactive but .git/rebase-merge.

Rename the 'am' backend to 'apply' because:
  * Few users are familiar with git-am as a reference point.
  * Related to the above, the name 'am' makes sentences in the
    documentation harder for users to read and comprehend (they may read
    it as the verb from "I am"); avoiding this difficult places a large
    burden on anyone writing documentation about this backend to be very
    careful with quoting and sentence structure and often forces
    annoying redundancy to try to avoid such problems.
  * Users stumble over pronunciation ("am" as in "I am a person not a
    backend" or "am" as in "the first and thirteenth letters in the
    alphabet in order are "A-M"); this may drive confusion when one user
    tries to explain to another what they are doing.
  * While "am" is the tool driving this backend, the tool driving git-am
    is git-apply, and since we are driving towards lower-level tools
    for the naming of the merge backend we may as well do so here too.
  * The directory where state is stored has never been called
    .git/rebase-am, it was always called .git/rebase-apply.

For all the reasons listed above:
  * Modify the documentation to refer to the backends with the new names
  * Provide a brief note in the documentation connecting the new names
    to the old names in case users run across the old names anywhere
    (e.g. in old release notes or older versions of the documentation)
  * Change the (new) --am command line flag to --apply
  * Rename some enums, variables, and functions to reinforce the new
    backend names for us as well.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-02-16 15:40:42 -08:00
Elijah Newren 2ac0d6273f rebase: change the default backend from "am" to "merge"
The am-backend drops information and thus limits what we can do:

  * lack of full tree information from the original commits means we
    cannot do directory rename detection and warn users that they might
    want to move some of their new files that they placed in old
    directories to prevent their becoming orphaned.[1]
  * reduction in context from only having a few lines beyond those
    changed means that when context lines are non-unique we can apply
    patches incorrectly.[2]
  * lack of access to original commits means that conflict marker
    annotation has less information available.
  * the am backend has safety problems with an ill-timed interrupt.

Also, the merge/interactive backend have far more abilities, appear to
currently have a slight performance advantage[3] and have room for more
optimizations than the am backend[4] (and work is underway to take
advantage of some of those possibilities).

[1] https://lore.kernel.org/git/xmqqh8jeh1id.fsf@gitster-ct.c.googlers.com/
[2] https://lore.kernel.org/git/CABPp-BGiu2nVMQY_t-rnFR5GQUz_ipyEE8oDocKeO+h+t4Mn4A@mail.gmail.com/
[3] https://public-inbox.org/git/CABPp-BF=ev03WgODk6TMQmuNoatg2kiEe5DR__gJ0OTVqHSnfQ@mail.gmail.com/
[4] https://lore.kernel.org/git/CABPp-BGh7yW69QwxQb13K0HM38NKmQif3A6C6UULEKYnkEJ5vA@mail.gmail.com/

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-02-16 15:40:42 -08:00
Elijah Newren 52eb738d6b rebase: add an --am option
Currently, this option doesn't do anything except error out if any
options requiring the interactive-backend are also passed.  However,
when we make the default backend configurable later in this series, this
flag will provide a way to override the config setting.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-02-16 15:40:42 -08:00
Elijah Newren be50c938df git-rebase.txt: add more details about behavioral differences of backends
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-02-16 15:40:42 -08:00
Elijah Newren e98c4269c8 rebase (interactive-backend): fix handling of commits that become empty
As established in the previous commit and commit b00bf1c9a8
(git-rebase: make --allow-empty-message the default, 2018-06-27), the
behavior for rebase with different backends in various edge or corner
cases is often more happenstance than design.  This commit addresses
another such corner case: commits which "become empty".

A careful reader may note that there are two types of commits which would
become empty due to a rebase:

  * [clean cherry-pick] Commits which are clean cherry-picks of upstream
    commits, as determined by `git log --cherry-mark ...`.  Re-applying
    these commits would result in an empty set of changes and a
    duplicative commit message; i.e. these are commits that have
    "already been applied" upstream.

  * [become empty] Commits which are not empty to start, are not clean
    cherry-picks of upstream commits, but which still become empty after
    being rebased.  This happens e.g. when a commit has changes which
    are a strict subset of the changes in an upstream commit, or when
    the changes of a commit can be found spread across or among several
    upstream commits.

Clearly, in both cases the changes in the commit in question are found
upstream already, but the commit message may not be in the latter case.

When cherry-mark can determine a commit is already upstream, then
because of how cherry-mark works this means the upstream commit message
was about the *exact* same set of changes.  Thus, the commit messages
can be assumed to be fully interchangeable (and are in fact likely to be
completely identical).  As such, the clean cherry-pick case represents a
case when there is no information to be gained by keeping the extra
commit around.  All rebase types have always dropped these commits, and
no one to my knowledge has ever requested that we do otherwise.

For many of the become empty cases (and likely even most), we will also
be able to drop the commit without loss of information -- but this isn't
quite always the case.  Since these commits represent cases that were
not clean cherry-picks, there is no upstream commit message explaining
the same set of changes.  Projects with good commit message hygiene will
likely have the explanation from our commit message contained within or
spread among the relevant upstream commits, but not all projects run
that way.  As such, the commit message of the commit being rebased may
have reasoning that suggests additional changes that should be made to
adapt to the new base, or it may have information that someone wants to
add as a note to another commit, or perhaps someone even wants to create
an empty commit with the commit message as-is.

Junio commented on the "become-empty" types of commits as follows[1]:

    WRT a change that ends up being empty (as opposed to a change that
    is empty from the beginning), I'd think that the current behaviour
    is desireable one.  "am" based rebase is solely to transplant an
    existing history and want to stop much less than "interactive" one
    whose purpose is to polish a series before making it publishable,
    and asking for confirmation ("this has become empty--do you want to
    drop it?") is more appropriate from the workflow point of view.

[1] https://lore.kernel.org/git/xmqqfu1fswdh.fsf@gitster-ct.c.googlers.com/

I would simply add that his arguments for "am"-based rebases actually
apply to all non-explicitly-interactive rebases.  Also, since we are
stating that different cases should have different defaults, it may be
worth providing a flag to allow users to select which behavior they want
for these commits.

Introduce a new command line flag for selecting the desired behavior:
    --empty={drop,keep,ask}
with the definitions:
    drop: drop commits which become empty
    keep: keep commits which become empty
    ask:  provide the user a chance to interact and pick what to do with
          commits which become empty on a case-by-case basis

In line with Junio's suggestion, if the --empty flag is not specified,
pick defaults as follows:
    explicitly interactive: ask
    otherwise: drop

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-02-16 15:40:42 -08:00
Elijah Newren d48e5e21da rebase (interactive-backend): make --keep-empty the default
Different rebase backends have different treatment for commits which
start empty (i.e. have no changes relative to their parent), and the
--keep-empty option was added at some point to allow adjusting behavior.
The handling of commits which start empty is actually quite similar to
commit b00bf1c9a8 (git-rebase: make --allow-empty-message the default,
2018-06-27), which pointed out that the behavior for various backends is
often more happenstance than design.  The specific change made in that
commit is actually quite relevant as well and much of the logic there
directly applies here.

It makes a lot of sense in 'git commit' to error out on the creation of
empty commits, unless an override flag is provided.  However, once
someone determines that there is a rare case that merits using the
manual override to create such a commit, it is somewhere between
annoying and harmful to have to take extra steps to keep such
intentional commits around.  Granted, empty commits are quite rare,
which is why handling of them doesn't get considered much and folks tend
to defer to existing (accidental) behavior and assume there was a reason
for it, leading them to just add flags (--keep-empty in this case) that
allow them to override the bad defaults.  Fix the interactive backend so
that --keep-empty is the default, much like we did with
--allow-empty-message.  The am backend should also be fixed to have
--keep-empty semantics for commits that start empty, but that is not
included in this patch other than a testcase documenting the failure.

Note that there was one test in t3421 which appears to have been written
expecting --keep-empty to not be the default as correct behavior.  This
test was introduced in commit 00b8be5a4d ("add tests for rebasing of
empty commits", 2013-06-06), which was part of a series focusing on
rebase topology and which had an interesting original cover letter at
https://lore.kernel.org/git/1347949878-12578-1-git-send-email-martinvonz@gmail.com/
which noted
    Your input especially appreciated on whether you agree with the
    intent of the test cases.
and then went into a long example about how one of the many tests added
had several questions about whether it was correct.  As such, I believe
most the tests in that series were about testing rebase topology with as
many different flags as possible and were not trying to state in general
how those flags should behave otherwise.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-02-16 15:40:42 -08:00
Elijah Newren 22a69fda19 git-rebase.txt: update description of --allow-empty-message
Commit b00bf1c9a8 ("git-rebase: make --allow-empty-message the
default", 2018-06-27) made --allow-empty-message the default and thus
turned --allow-empty-message into a no-op but did not update the
documentation to reflect this.  Update the documentation now, and hide
the option from the normal -h output since it is not useful.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-01-17 13:58:30 -08:00
Junio C Hamano 4d924528d8 Revert "Merge branch 'ra/rebase-i-more-options'"
This reverts commit 5d9324e0f4, reversing
changes made to c58ae96fc4.

The topic turns out to be too buggy for real use.

cf. <f2fe7437-8a48-3315-4d3f-8d51fe4bb8f1@gmail.com>
2020-01-12 13:25:18 -08:00
Junio C Hamano 5d9324e0f4 Merge branch 'ra/rebase-i-more-options'
"git rebase -i" learned a few options that are known by "git
rebase" proper.

* ra/rebase-i-more-options:
  rebase -i: finishing touches to --reset-author-date
  rebase: add --reset-author-date
  rebase -i: support --ignore-date
  sequencer: rename amend_author to author_to_rename
  rebase -i: support --committer-date-is-author-date
  sequencer: allow callers of read_author_script() to ignore fields
  rebase -i: add --ignore-whitespace flag
2019-12-10 13:11:41 -08:00
Junio C Hamano d82dfa7f5b rebase -i: finishing touches to --reset-author-date
Clarify the way the `--reset-author-date` option is described,
and mark its usage string translatable.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-11-25 15:09:29 +09:00
Naveen Nathan d3a8caebf3 doc: improve readability of --rebase-merges in git-rebase
When --preserve-merges was deprecated in 427c3bd28a a sentence
was introduced describing the difference between --rebase-merges and
--preserve-merges which is a little unclear and difficult to parse.
This patch improves readability while retaining original meaning.

Signed-off-by: Naveen Nathan <naveen@lastninja.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-11-12 13:14:19 +09:00
Rohit Ashiwal fe28ad8520 rebase: add --reset-author-date
The previous commit introduced --ignore-date flag to interactive
rebase, but the name is actually very vague in context of rebase -i
since there are two dates we can work with. Add an alias to convey
the precise purpose.

Signed-off-by: Rohit Ashiwal <rohit.ashiwal265@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-11-02 15:37:12 +09:00
Rohit Ashiwal 08187b4cba rebase -i: support --ignore-date
rebase am already has this flag to "lie" about the author date
by changing it to the committer (current) date. Let's add the same
for interactive machinery.

Signed-off-by: Rohit Ashiwal <rohit.ashiwal265@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-11-02 15:37:12 +09:00
Rohit Ashiwal cbd8db17ac rebase -i: support --committer-date-is-author-date
rebase am already has this flag to "lie" about the committer date
by changing it to the author date. Let's add the same for
interactive machinery.

Signed-off-by: Rohit Ashiwal <rohit.ashiwal265@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-11-02 15:36:23 +09:00
Rohit Ashiwal ba51d2fb24 rebase -i: add --ignore-whitespace flag
There are two backends available for rebasing, viz, the am and the
interactive. Naturally, there shall be some features that are
implemented in one but not in the other. One such flag is
--ignore-whitespace which indicates merge mechanism to treat lines
with only whitespace changes as unchanged. Wire the interactive
rebase to also understand the --ignore-whitespace flag by
translating it to -Xignore-space-change.

Signed-off-by: Rohit Ashiwal <rohit.ashiwal265@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-11-02 15:34:50 +09:00
Junio C Hamano 640f9cd599 Merge branch 'dl/rebase-i-keep-base'
"git rebase --keep-base <upstream>" tries to find the original base
of the topic being rebased and rebase on top of that same base,
which is useful when running the "git rebase -i" (and its limited
variant "git rebase -x").

The command also has learned to fast-forward in more cases where it
can instead of replaying to recreate identical commits.

* dl/rebase-i-keep-base:
  rebase: teach rebase --keep-base
  rebase tests: test linear branch topology
  rebase: fast-forward --fork-point in more cases
  rebase: fast-forward --onto in more cases
  rebase: refactor can_fast_forward into goto tower
  t3432: test for --no-ff's interaction with fast-forward
  t3432: distinguish "noop-same" v.s. "work-same" in "same head" tests
  t3432: test rebase fast-forward behavior
  t3431: add rebase --fork-point tests
2019-09-30 13:19:31 +09:00
Junio C Hamano 91243b019d Merge branch 'en/filter-branch-deprecation'
Start discouraging the use of "git filter-branch".

* en/filter-branch-deprecation:
  t9902: use a non-deprecated command for testing
  Recommend git-filter-repo instead of git-filter-branch
  t6006: simplify, fix, and optimize empty message test
2019-09-30 13:19:29 +09:00
Junio C Hamano 917a319ea5 Merge branch 'js/rebase-r-strategy'
"git rebase --rebase-merges" learned to drive different merge
strategies and pass strategy specific options to them.

* js/rebase-r-strategy:
  t3427: accelerate this test by using fast-export and fast-import
  rebase -r: do not (re-)generate root commits with `--root` *and* `--onto`
  t3418: test `rebase -r` with merge strategies
  t/lib-rebase: prepare for testing `git rebase --rebase-merges`
  rebase -r: support merge strategies other than `recursive`
  t3427: fix another incorrect assumption
  t3427: accommodate for the `rebase --merge` backend having been replaced
  t3427: fix erroneous assumption
  t3427: condense the unnecessarily repetitive test cases into three
  t3427: move the `filter-branch` invocation into the `setup` case
  t3427: simplify the `setup` test case significantly
  t3427: add a clarifying comment
  rebase: fold git-rebase--common into the -p backend
  sequencer: the `am` and `rebase--interactive` scripts are gone
  .gitignore: there is no longer a built-in `git-rebase--interactive`
  t3400: stop referring to the scripted rebase
  Drop unused git-rebase--am.sh
2019-09-18 11:50:07 -07:00
Elijah Newren 9df53c5de6 Recommend git-filter-repo instead of git-filter-branch
filter-branch suffers from a deluge of disguised dangers that disfigure
history rewrites (i.e. deviate from the deliberate changes).  Many of
these problems are unobtrusive and can easily go undiscovered until the
new repository is in use.  This can result in problems ranging from an
even messier history than what led folks to filter-branch in the first
place, to data loss or corruption.  These issues cannot be backward
compatibly fixed, so add a warning to both filter-branch and its manpage
recommending that another tool (such as filter-repo) be used instead.

Also, update other manpages that referenced filter-branch.  Several of
these needed updates even if we could continue recommending
filter-branch, either due to implying that something was unique to
filter-branch when it applied more generally to all history rewriting
tools (e.g. BFG, reposurgeon, fast-import, filter-repo), or because
something about filter-branch was used as an example despite other more
commonly known examples now existing.  Reword these sections to fix
these issues and to avoid recommending filter-branch.

Finally, remove the section explaining BFG Repo Cleaner as an
alternative to filter-branch.  I feel somewhat bad about this,
especially since I feel like I learned so much from BFG that I put to
good use in filter-repo (which is much more than I can say for
filter-branch), but keeping that section presented a few problems:
  * In order to recommend that people quit using filter-branch, we need
    to provide them a recomendation for something else to use that
    can handle all the same types of rewrites.  To my knowledge,
    filter-repo is the only such tool.  So it needs to be mentioned.
  * I don't want to give conflicting recommendations to users
  * If we recommend two tools, we shouldn't expect users to learn both
    and pick which one to use; we should explain which problems one
    can solve that the other can't or when one is much faster than
    the other.
  * BFG and filter-repo have similar performance
  * All filtering types that BFG can do, filter-repo can also do.  In
    fact, filter-repo comes with a reimplementation of BFG named
    bfg-ish which provides the same user-interface as BFG but with
    several bugfixes and new features that are hard to implement in
    BFG due to its technical underpinnings.
While I could still mention both tools, it seems like I would need to
provide some kind of comparison and I would ultimately just say that
filter-repo can do everything BFG can, so ultimately it seems that it
is just better to remove that section altogether.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-09-05 13:01:48 -07:00
Denton Liu 414d924beb rebase: teach rebase --keep-base
A common scenario is if a user is working on a topic branch and they
wish to make some changes to intermediate commits or autosquash, they
would run something such as

	git rebase -i --onto master... master

in order to preserve the merge base. This is useful when contributing a
patch series to the Git mailing list, one often starts on top of the
current 'master'. While developing the patches, 'master' is also
developed further and it is sometimes not the best idea to keep rebasing
on top of 'master', but to keep the base commit as-is.

In addition to this, a user wishing to test individual commits in a
topic branch without changing anything may run

	git rebase -x ./test.sh master... master

Since rebasing onto the merge base of the branch and the upstream is
such a common case, introduce the --keep-base option as a shortcut.

This allows us to rewrite the above as

	git rebase -i --keep-base master

and

	git rebase -x ./test.sh --keep-base master

respectively.

Add tests to ensure --keep-base works correctly in the normal case and
fails when there are multiple merge bases, both in regular and
interactive mode. Also, test to make sure conflicting options cause
rebase to fail. While we're adding test cases, add a missing
set_fake_editor call to 'rebase -i --onto master...side'.

While we're documenting the --keep-base option, change an instance of
"merge-base" to "merge base", which is the consistent spelling.

Helped-by: Eric Sunshine <sunshine@sunshineco.com>
Helped-by: Junio C Hamano <gitster@pobox.com>
Helped-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Helped-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
Signed-off-by: Denton Liu <liu.denton@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-08-27 15:33:40 -07:00