rebase: learn to rebase root commit
Teach git-rebase a new option --root, which instructs it to rebase the entire history leading up to <branch>. This option must be used with --onto <newbase>, and causes commits that already exist in <newbase> to be skipped. (Normal operation skips commits that already exist in <upstream> instead.) One possible use-case is with git-svn: suppose you start hacking (perhaps offline) on a new project, but later notice you want to commit this work to SVN. You will have to rebase the entire history, including the root commit, on a (possibly empty) commit coming from git-svn, to establish a history connection. This previously had to be done by cherry-picking the root commit manually. Signed-off-by: Thomas Rast <trast@student.ethz.ch> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Thomas Rast committed
Jan 5, 2009 at 18:35 UTC
190f53232d1e92a57843df90e889bcfea39620d3
2 files changed
+126
-16
git-rebase.sh
+40
-16
@@ -3,7 +3,7 @@
3
# Copyright (c) 2005 Junio C Hamano.
4
#
5
6
-USAGE='[--interactive | -i] [-v] [--onto <newbase>] <upstream> [<branch>]'
6
+USAGE='[--interactive | -i] [-v] [--onto <newbase>] [<upstream>|--root] [<branch>]'
7
LONG_USAGE='git-rebase replaces <branch> with a new branch of the
8
same name. When the --onto option is provided the new branch starts
9
out with a HEAD equal to <newbase>, otherwise it is equal to <upstream>
@@ -47,6 +47,7 @@ dotest="$GIT_DIR"/rebase-merge
47
prec=4
48
verbose=
49
git_am_opt=
50
+rebase_root=
51
52
continue_merge () {
53
test -n "$prev_head" || die "prev_head must be defined"
@@ -297,6 +298,9 @@ do
298
-C*)
299
git_am_opt="$git_am_opt $1"
300
;;
301
+ --root)
302
+ rebase_root=t
303
+ ;;
304
-*)
305
usage
306
;;
@@ -344,17 +348,29 @@ case "$diff" in
348
;;
349
esac
350
347
-# The upstream head must be given. Make sure it is valid.
348
-upstream_name="$1"
349
-upstream=`git rev-parse --verify "${upstream_name}^0"` ||
350
- die "invalid upstream $upstream_name"
351
+if test -z "$rebase_root"
352
+then
353
+ # The upstream head must be given. Make sure it is valid.
354
+ upstream_name="$1"
355
+ shift
356
+ upstream=`git rev-parse --verify "${upstream_name}^0"` ||
357
+ die "invalid upstream $upstream_name"
358
+ unset root_flag
359
+ upstream_arg="$upstream_name"
360
+else
361
+ test -z "$newbase" && die "--root must be used with --onto"
362
+ unset upstream_name
363
+ unset upstream
364
+ root_flag="--root"
365
+ upstream_arg="$root_flag"
366
+fi
367
368
# Make sure the branch to rebase onto is valid.
369
onto_name=${newbase-"$upstream_name"}
370
onto=$(git rev-parse --verify "${onto_name}^0") || exit
371
372
# If a hook exists, give it a chance to interrupt
357
-run_pre_rebase_hook ${1+"$@"}
373
+run_pre_rebase_hook "$upstream_arg" "$@"
374
375
# If the branch to rebase is given, that is the branch we will rebase
376
# $branch_name -- branch being rebased, or HEAD (already detached)
@@ -362,16 +378,16 @@ run_pre_rebase_hook ${1+"$@"}
378
# $head_name -- refs/heads/<that-branch> or "detached HEAD"
379
switch_to=
380
case "$#" in
365
-2)
381
+1)
382
# Is it "rebase other $branchname" or "rebase other $commit"?
367
- branch_name="$2"
368
- switch_to="$2"
383
+ branch_name="$1"
384
+ switch_to="$1"
385
370
- if git show-ref --verify --quiet -- "refs/heads/$2" &&
371
- branch=$(git rev-parse -q --verify "refs/heads/$2")
386
+ if git show-ref --verify --quiet -- "refs/heads/$1" &&
387
+ branch=$(git rev-parse -q --verify "refs/heads/$1")
388
then
373
- head_name="refs/heads/$2"
374
- elif branch=$(git rev-parse -q --verify "$2")
389
+ head_name="refs/heads/$1"
390
+ elif branch=$(git rev-parse -q --verify "$1")
391
then
392
head_name="detached HEAD"
393
else
@@ -393,7 +409,8 @@ case "$#" in
409
esac
410
orig_head=$branch
411
396
-# Now we are rebasing commits $upstream..$branch on top of $onto
412
+# Now we are rebasing commits $upstream..$branch (or with --root,
413
+# everything leading up to $branch) on top of $onto
414
415
# Check if we are already based on $onto with linear history,
416
# but this should be done only when upstream and onto are the same.
@@ -429,10 +446,17 @@ then
446
exit 0
447
fi
448
449
+if test -n "$rebase_root"
450
+then
451
+ revisions="$onto..$orig_head"
452
+else
453
+ revisions="$upstream..$orig_head"
454
+fi
455
+
456
if test -z "$do_merge"
457
then
458
git format-patch -k --stdout --full-index --ignore-if-in-upstream \
435
- "$upstream..$orig_head" |
459
+ $root_flag "$revisions" |
460
git am $git_am_opt --rebasing --resolvemsg="$RESOLVEMSG" &&
461
move_to_original_branch
462
ret=$?
@@ -455,7 +479,7 @@ echo "$orig_head" > "$dotest/orig-head"
479
echo "$head_name" > "$dotest/head-name"
480
481
msgnum=0
458
-for cmt in `git rev-list --reverse --no-merges "$upstream..$orig_head"`
482
+for cmt in `git rev-list --reverse --no-merges "$revisions"`
483
do
484
msgnum=$(($msgnum + 1))
485
echo "$cmt" > "$dotest/cmt.$msgnum"
t/t3412-rebase-root.sh
new
+86
@@ -0,0 +1,86 @@
1
+#!/bin/sh
2
+
3
+test_description='git rebase --root
4
+
5
+Tests if git rebase --root --onto <newparent> can rebase the root commit.
6
+'
7
+. ./test-lib.sh
8
+
9
+test_expect_success 'prepare repository' '
10
+ echo 1 > A &&
11
+ git add A &&
12
+ git commit -m 1 &&
13
+ echo 2 > A &&
14
+ git add A &&
15
+ git commit -m 2 &&
16
+ git symbolic-ref HEAD refs/heads/other &&
17
+ rm .git/index &&
18
+ echo 3 > B &&
19
+ git add B &&
20
+ git commit -m 3 &&
21
+ echo 1 > A &&
22
+ git add A &&
23
+ git commit -m 1b &&
24
+ echo 4 > B &&
25
+ git add B &&
26
+ git commit -m 4
27
+'
28
+
29
+test_expect_success 'rebase --root expects --onto' '
30
+ test_must_fail git rebase --root
31
+'
32
+
33
+test_expect_success 'setup pre-rebase hook' '
34
+ mkdir -p .git/hooks &&
35
+ cat >.git/hooks/pre-rebase <<EOF &&
36
+#!$SHELL_PATH
37
+echo "\$1,\$2" >.git/PRE-REBASE-INPUT
38
+EOF
39
+ chmod +x .git/hooks/pre-rebase
40
+'
41
+cat > expect <<EOF
42
+4
43
+3
44
+2
45
+1
46
+EOF
47
+
48
+test_expect_success 'rebase --root --onto <newbase>' '
49
+ git checkout -b work &&
50
+ git rebase --root --onto master &&
51
+ git log --pretty=tformat:"%s" > rebased &&
52
+ test_cmp expect rebased
53
+'
54
+
55
+test_expect_success 'pre-rebase got correct input (1)' '
56
+ test "z$(cat .git/PRE-REBASE-INPUT)" = z--root,
57
+'
58
+
59
+test_expect_success 'rebase --root --onto <newbase> <branch>' '
60
+ git branch work2 other &&
61
+ git rebase --root --onto master work2 &&
62
+ git log --pretty=tformat:"%s" > rebased2 &&
63
+ test_cmp expect rebased2
64
+'
65
+
66
+test_expect_success 'pre-rebase got correct input (2)' '
67
+ test "z$(cat .git/PRE-REBASE-INPUT)" = z--root,work2
68
+'
69
+
70
+test_expect_success 'setup pre-rebase hook that fails' '
71
+ mkdir -p .git/hooks &&
72
+ cat >.git/hooks/pre-rebase <<EOF &&
73
+#!$SHELL_PATH
74
+false
75
+EOF
76
+ chmod +x .git/hooks/pre-rebase
77
+'
78
+
79
+test_expect_success 'pre-rebase hook stops rebase' '
80
+ git checkout -b stops1 other &&
81
+ GIT_EDITOR=: test_must_fail git rebase --root --onto master &&
82
+ test "z$(git symbolic-ref HEAD)" = zrefs/heads/stops1
83
+ test 0 = $(git rev-list other...stops1 | wc -l)
84
+'
85
+
86
+test_done