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Merge branch 'dl/rebase-i-keep-base'

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"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
This commit is contained in:
Junio C Hamano 2019-09-30 13:19:31 +09:00
commit 640f9cd599
9 changed files with 360 additions and 28 deletions
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30
Documentation/git-rebase.txt
View File

@ -8,8 +8,8 @@ git-rebase - Reapply commits on top of another base tip
SYNOPSIS
--------
[verse]
'git rebase' [-i | --interactive] [<options>] [--exec <cmd>] [--onto <newbase>]
[<upstream> [<branch>]]
'git rebase' [-i | --interactive] [<options>] [--exec <cmd>]
[--onto <newbase> | --keep-base] [<upstream> [<branch>]]
'git rebase' [-i | --interactive] [<options>] [--exec <cmd>] [--onto <newbase>]
--root [<branch>]
'git rebase' (--continue | --skip | --abort | --quit | --edit-todo | --show-current-patch)
@ -217,6 +217,24 @@ As a special case, you may use "A\...B" as a shortcut for the
merge base of A and B if there is exactly one merge base. You can
leave out at most one of A and B, in which case it defaults to HEAD.
--keep-base::
Set the starting point at which to create the new commits to the
merge base of <upstream> <branch>. Running
'git rebase --keep-base <upstream> <branch>' is equivalent to
running 'git rebase --onto <upstream>... <upstream>'.
+
This option is useful in the case where one is developing a feature on
top of an upstream branch. While the feature is being worked on, the
upstream branch may advance and it may not be the best idea to keep
rebasing on top of the upstream but to keep the base commit as-is.
+
Although both this option and --fork-point find the merge base between
<upstream> and <branch>, this option uses the merge base as the _starting
point_ on which new commits will be created, whereas --fork-point uses
the merge base to determine the _set of commits_ which will be rebased.
+
See also INCOMPATIBLE OPTIONS below.
<upstream>::
Upstream branch to compare against. May be any valid commit,
not just an existing branch name. Defaults to the configured
@ -369,6 +387,10 @@ ends up being empty, the <upstream> will be used as a fallback.
+
If either <upstream> or --root is given on the command line, then the
default is `--no-fork-point`, otherwise the default is `--fork-point`.
+
If your branch was based on <upstream> but <upstream> was rewound and
your branch contains commits which were dropped, this option can be used
with `--keep-base` in order to drop those commits from your branch.
--ignore-whitespace::
--whitespace=<option>::
@ -543,6 +565,8 @@ In addition, the following pairs of options are incompatible:
* --preserve-merges and --interactive
* --preserve-merges and --signoff
* --preserve-merges and --rebase-merges
* --keep-base and --onto
* --keep-base and --root
BEHAVIORAL DIFFERENCES
-----------------------
@ -869,7 +893,7 @@ NOTE: While an "easy case recovery" sometimes appears to be successful
--interactive` will be **resurrected**!
The idea is to manually tell 'git rebase' "where the old 'subsystem'
ended and your 'topic' began", that is, what the old merge-base
ended and your 'topic' began", that is, what the old merge base
between them was. You will have to find a way to name the last commit
of the old 'subsystem', for example:

84
builtin/rebase.c
View File

@ -29,8 +29,8 @@
#include "rebase-interactive.h"
static char const * const builtin_rebase_usage[] = {
N_("git rebase [-i] [options] [--exec <cmd>] [--onto <newbase>] "
"[<upstream>] [<branch>]"),
N_("git rebase [-i] [options] [--exec <cmd>] "
"[--onto <newbase> | --keep-base] [<upstream> [<branch>]]"),
N_("git rebase [-i] [options] [--exec <cmd>] [--onto <newbase>] "
"--root [<branch>]"),
N_("git rebase --continue | --abort | --skip | --edit-todo"),
@ -1261,24 +1261,44 @@ static int is_linear_history(struct commit *from, struct commit *to)
return 1;
}
static int can_fast_forward(struct commit *onto, struct object_id *head_oid,
struct object_id *merge_base)
static int can_fast_forward(struct commit *onto, struct commit *upstream,
struct commit *restrict_revision,
struct object_id *head_oid, struct object_id *merge_base)
{
struct commit *head = lookup_commit(the_repository, head_oid);
struct commit_list *merge_bases;
int res;
struct commit_list *merge_bases = NULL;
int res = 0;
if (!head)
return 0;
goto done;
merge_bases = get_merge_bases(onto, head);
if (merge_bases && !merge_bases->next) {
oidcpy(merge_base, &merge_bases->item->object.oid);
res = oideq(merge_base, &onto->object.oid);
} else {
if (!merge_bases || merge_bases->next) {
oidcpy(merge_base, &null_oid);
res = 0;
goto done;
}
oidcpy(merge_base, &merge_bases->item->object.oid);
if (!oideq(merge_base, &onto->object.oid))
goto done;
if (restrict_revision && !oideq(&restrict_revision->object.oid, merge_base))
goto done;
if (!upstream)
goto done;
free_commit_list(merge_bases);
merge_bases = get_merge_bases(upstream, head);
if (!merge_bases || merge_bases->next)
goto done;
if (!oideq(&onto->object.oid, &merge_bases->item->object.oid))
goto done;
res = 1;
done:
free_commit_list(merge_bases);
return res && is_linear_history(onto, head);
}
@ -1377,6 +1397,7 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
struct rebase_options options = REBASE_OPTIONS_INIT;
const char *branch_name;
int ret, flags, total_argc, in_progress = 0;
int keep_base = 0;
int ok_to_skip_pre_rebase = 0;
struct strbuf msg = STRBUF_INIT;
struct strbuf revisions = STRBUF_INIT;
@ -1395,6 +1416,8 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
OPT_STRING(0, "onto", &options.onto_name,
N_("revision"),
N_("rebase onto given branch instead of upstream")),
OPT_BOOL(0, "keep-base", &keep_base,
N_("use the merge-base of upstream and branch as the current base")),
OPT_BOOL(0, "no-verify", &ok_to_skip_pre_rebase,
N_("allow pre-rebase hook to run")),
OPT_NEGBIT('q', "quiet", &options.flags,
@ -1548,6 +1571,13 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
warning(_("git rebase --preserve-merges is deprecated. "
"Use --rebase-merges instead."));
if (keep_base) {
if (options.onto_name)
die(_("cannot combine '--keep-base' with '--onto'"));
if (options.root)
die(_("cannot combine '--keep-base' with '--root'"));
}
if (action != ACTION_NONE && !in_progress)
die(_("No rebase in progress?"));
setenv(GIT_REFLOG_ACTION_ENVIRONMENT, "rebase", 0);
@ -1876,12 +1906,22 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
}
/* Make sure the branch to rebase onto is valid. */
if (!options.onto_name)
if (keep_base) {
strbuf_reset(&buf);
strbuf_addstr(&buf, options.upstream_name);
strbuf_addstr(&buf, "...");
options.onto_name = xstrdup(buf.buf);
} else if (!options.onto_name)
options.onto_name = options.upstream_name;
if (strstr(options.onto_name, "...")) {
if (get_oid_mb(options.onto_name, &merge_base) < 0)
die(_("'%s': need exactly one merge base"),
options.onto_name);
if (get_oid_mb(options.onto_name, &merge_base) < 0) {
if (keep_base)
die(_("'%s': need exactly one merge base with branch"),
options.upstream_name);
else
die(_("'%s': need exactly one merge base"),
options.onto_name);
}
options.onto = lookup_commit_or_die(&merge_base,
options.onto_name);
} else {
@ -2016,13 +2056,13 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
/*
* Check if we are already based on onto with linear history,
* but this should be done only when upstream and onto are the same
* and if this is not an interactive rebase.
* in which case we could fast-forward without replacing the commits
* with new commits recreated by replaying their changes. This
* optimization must not be done if this is an interactive rebase.
*/
if (can_fast_forward(options.onto, &options.orig_head, &merge_base) &&
!is_interactive(&options) && !options.restrict_revision &&
options.upstream &&
!oidcmp(&options.upstream->object.oid, &options.onto->object.oid)) {
if (can_fast_forward(options.onto, options.upstream, options.restrict_revision,
&options.orig_head, &merge_base) &&
!is_interactive(&options)) {
int flag;
if (!(options.flags & REBASE_FORCE)) {

2
contrib/completion/git-completion.bash
View File

@ -2043,7 +2043,7 @@ _git_rebase ()
--autosquash --no-autosquash
--fork-point --no-fork-point
--autostash --no-autostash
--verify --no-verify
--verify --no-verify --keep-base
--keep-empty --root --force-rebase --no-ff
--rerere-autoupdate
--exec

2
t/t3400-rebase.sh
View File

@ -295,7 +295,7 @@ test_expect_success 'rebase --am and --show-current-patch' '
echo two >>init.t &&
git commit -a -m two &&
git tag two &&
test_must_fail git rebase --onto init HEAD^ &&
test_must_fail git rebase -f --onto init HEAD^ &&
GIT_TRACE=1 git rebase --show-current-patch >/dev/null 2>stderr &&
grep "show.*$(git rev-parse two)" stderr
)

2
t/t3404-rebase-interactive.sh
View File

@ -1056,7 +1056,7 @@ test_expect_success C_LOCALE_OUTPUT 'rebase --edit-todo does not work on non-int
git reset --hard &&
git checkout conflict-branch &&
set_fake_editor &&
test_must_fail git rebase --onto HEAD~2 HEAD~ &&
test_must_fail git rebase -f --onto HEAD~2 HEAD~ &&
test_must_fail git rebase --edit-todo &&
git rebase --abort
'

57
t/t3416-rebase-onto-threedots.sh
View File

@ -99,7 +99,64 @@ test_expect_success 'rebase -i --onto master...side' '
git checkout side &&
git reset --hard K &&
set_fake_editor &&
test_must_fail git rebase -i --onto master...side J
'
test_expect_success 'rebase --keep-base --onto incompatible' '
test_must_fail git rebase --keep-base --onto master...
'
test_expect_success 'rebase --keep-base --root incompatible' '
test_must_fail git rebase --keep-base --root
'
test_expect_success 'rebase --keep-base master from topic' '
git reset --hard &&
git checkout topic &&
git reset --hard G &&
git rebase --keep-base master &&
git rev-parse C >base.expect &&
git merge-base master HEAD >base.actual &&
test_cmp base.expect base.actual &&
git rev-parse HEAD~2 >actual &&
git rev-parse C^0 >expect &&
test_cmp expect actual
'
test_expect_success 'rebase --keep-base master from side' '
git reset --hard &&
git checkout side &&
git reset --hard K &&
test_must_fail git rebase --keep-base master
'
test_expect_success 'rebase -i --keep-base master from topic' '
git reset --hard &&
git checkout topic &&
git reset --hard G &&
set_fake_editor &&
EXPECT_COUNT=2 git rebase -i --keep-base master &&
git rev-parse C >base.expect &&
git merge-base master HEAD >base.actual &&
test_cmp base.expect base.actual &&
git rev-parse HEAD~2 >actual &&
git rev-parse C^0 >expect &&
test_cmp expect actual
'
test_expect_success 'rebase -i --keep-base master from side' '
git reset --hard &&
git checkout side &&
git reset --hard K &&
set_fake_editor &&
test_must_fail git rebase -i --keep-base master
'
test_done

29
t/t3421-rebase-topology-linear.sh
View File

@ -31,6 +31,16 @@ test_run_rebase success -m
test_run_rebase success -i
test_have_prereq !REBASE_P || test_run_rebase success -p
test_expect_success 'setup branches and remote tracking' '
git tag -l >tags &&
for tag in $(cat tags)
do
git branch branch-$tag $tag || return 1
done &&
git remote add origin "file://$PWD" &&
git fetch origin
'
test_run_rebase () {
result=$1
shift
@ -57,10 +67,28 @@ test_run_rebase () {
"
}
test_run_rebase success ''
test_run_rebase success --fork-point
test_run_rebase success -m
test_run_rebase success -i
test_have_prereq !REBASE_P || test_run_rebase failure -p
test_run_rebase () {
result=$1
shift
test_expect_$result "rebase $* -f rewrites even if remote upstream is an ancestor" "
reset_rebase &&
git rebase $* -f branch-b branch-e &&
! test_cmp_rev branch-e origin/branch-e &&
test_cmp_rev branch-b HEAD~2 &&
test_linear_range 'd e' branch-b..
"
}
test_run_rebase success ''
test_run_rebase success --fork-point
test_run_rebase success -m
test_run_rebase success -i
test_have_prereq !REBASE_P || test_run_rebase success -p
test_run_rebase () {
result=$1
shift
@ -71,6 +99,7 @@ test_run_rebase () {
"
}
test_run_rebase success ''
test_run_rebase success --fork-point
test_run_rebase success -m
test_run_rebase success -i
test_have_prereq !REBASE_P || test_run_rebase success -p

57
t/t3431-rebase-fork-point.sh Executable file
View File

@ -0,0 +1,57 @@
#!/bin/sh
#
# Copyright (c) 2019 Denton Liu
#
test_description='git rebase --fork-point test'
. ./test-lib.sh
# A---B---D---E (master)
# \
# C*---F---G (side)
#
# C was formerly part of master but master was rewound to remove C
#
test_expect_success setup '
test_commit A &&
test_commit B &&
test_commit C &&
git branch -t side &&
git reset --hard HEAD^ &&
test_commit D &&
test_commit E &&
git checkout side &&
test_commit F &&
test_commit G
'
test_rebase () {
expected="$1" &&
shift &&
test_expect_success "git rebase $*" "
git checkout master &&
git reset --hard E &&
git checkout side &&
git reset --hard G &&
git rebase $* &&
test_write_lines $expected >expect &&
git log --pretty=%s >actual &&
test_cmp expect actual
"
}
test_rebase 'G F E D B A'
test_rebase 'G F D B A' --onto D
test_rebase 'G F B A' --keep-base
test_rebase 'G F C E D B A' --no-fork-point
test_rebase 'G F C D B A' --no-fork-point --onto D
test_rebase 'G F C B A' --no-fork-point --keep-base
test_rebase 'G F E D B A' --fork-point refs/heads/master
test_rebase 'G F D B A' --fork-point --onto D refs/heads/master
test_rebase 'G F B A' --fork-point --keep-base refs/heads/master
test_rebase 'G F C E D B A' refs/heads/master
test_rebase 'G F C D B A' --onto D refs/heads/master
test_rebase 'G F C B A' --keep-base refs/heads/master
test_done

125
t/t3432-rebase-fast-forward.sh Executable file
View File

@ -0,0 +1,125 @@
#!/bin/sh
#
# Copyright (c) 2019 Denton Liu
#
test_description='ensure rebase fast-forwards commits when possible'
. ./test-lib.sh
test_expect_success setup '
test_commit A &&
test_commit B &&
test_commit C &&
test_commit D &&
git checkout -t -b side
'
test_rebase_same_head () {
status_n="$1" &&
shift &&
what_n="$1" &&
shift &&
cmp_n="$1" &&
shift &&
status_f="$1" &&
shift &&
what_f="$1" &&
shift &&
cmp_f="$1" &&
shift &&
test_rebase_same_head_ $status_n $what_n $cmp_n "" "$*" &&
test_rebase_same_head_ $status_f $what_f $cmp_f " --no-ff" "$*"
}
test_rebase_same_head_ () {
status="$1" &&
shift &&
what="$1" &&
shift &&
cmp="$1" &&
shift &&
flag="$1"
shift &&
test_expect_$status "git rebase$flag $* with $changes is $what with $cmp HEAD" "
oldhead=\$(git rev-parse HEAD) &&
test_when_finished 'git reset --hard \$oldhead' &&
git rebase$flag $* >stdout &&
if test $what = work
then
# Must check this case first, for 'is up to
# date, rebase forced[...]rewinding head' cases
test_i18ngrep 'rewinding head' stdout
elif test $what = noop
then
test_i18ngrep 'is up to date' stdout &&
test_i18ngrep ! 'rebase forced' stdout
elif test $what = noop-force
then
test_i18ngrep 'is up to date, rebase forced' stdout
fi &&
newhead=\$(git rev-parse HEAD) &&
if test $cmp = same
then
test_cmp_rev \$oldhead \$newhead
elif test $cmp = diff
then
! test_cmp_rev \$oldhead \$newhead
fi
"
}
changes='no changes'
test_rebase_same_head success noop same success work same
test_rebase_same_head success noop same success noop-force same master
test_rebase_same_head success noop same success noop-force diff --onto B B
test_rebase_same_head success noop same success noop-force diff --onto B... B
test_rebase_same_head success noop same success noop-force same --onto master... master
test_rebase_same_head success noop same success noop-force same --keep-base master
test_rebase_same_head success noop same success noop-force same --keep-base
test_rebase_same_head success noop same success noop-force same --no-fork-point
test_rebase_same_head success noop same success noop-force same --keep-base --no-fork-point
test_rebase_same_head success noop same success work same --fork-point master
test_rebase_same_head success noop same success work diff --fork-point --onto B B
test_rebase_same_head success noop same success work diff --fork-point --onto B... B
test_rebase_same_head success noop same success work same --fork-point --onto master... master
test_rebase_same_head success noop same success work same --keep-base --keep-base master
test_expect_success 'add work same to side' '
test_commit E
'
changes='our changes'
test_rebase_same_head success noop same success work same
test_rebase_same_head success noop same success noop-force same master
test_rebase_same_head success noop same success noop-force diff --onto B B
test_rebase_same_head success noop same success noop-force diff --onto B... B
test_rebase_same_head success noop same success noop-force same --onto master... master
test_rebase_same_head success noop same success noop-force same --keep-base master
test_rebase_same_head success noop same success noop-force same --keep-base
test_rebase_same_head success noop same success noop-force same --no-fork-point
test_rebase_same_head success noop same success noop-force same --keep-base --no-fork-point
test_rebase_same_head success noop same success work same --fork-point master
test_rebase_same_head success noop same success work diff --fork-point --onto B B
test_rebase_same_head success noop same success work diff --fork-point --onto B... B
test_rebase_same_head success noop same success work same --fork-point --onto master... master
test_rebase_same_head success noop same success work same --fork-point --keep-base master
test_expect_success 'add work same to upstream' '
git checkout master &&
test_commit F &&
git checkout side
'
changes='our and their changes'
test_rebase_same_head success noop same success noop-force diff --onto B B
test_rebase_same_head success noop same success noop-force diff --onto B... B
test_rebase_same_head success noop same success work diff --onto master... master
test_rebase_same_head success noop same success work diff --keep-base master
test_rebase_same_head success noop same success work diff --keep-base
test_rebase_same_head failure work same success work diff --fork-point --onto B B
test_rebase_same_head failure work same success work diff --fork-point --onto B... B
test_rebase_same_head success noop same success work diff --fork-point --onto master... master
test_rebase_same_head success noop same success work diff --fork-point --keep-base master
test_done