pull: allow pull to preserve merges when rebasing

If a user is working on master, and has merged in their feature branch, but now has to "git pull" because master moved, with pull.rebase their feature branch will be flattened into master. This is because "git pull" currently does not know about rebase's preserve merges flag, which would avoid this behavior, as it would instead replay just the merge commit of the feature branch onto the new master, and not replay each individual commit in the feature branch. Add a --rebase=preserve option, which will pass along --preserve-merges to rebase. Also add 'preserve' to the allowed values for the pull.rebase config setting. Signed-off-by: Stephen Haberman <stephen@exigencecorp.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Stephen Haberman committed Aug 12, 2013 at 22:43 UTC 66713ef3b00933755cdeff1ae823dda7b5843640
4 files changed +135 -11
Documentation/config.txt
+8
@@ -765,6 +765,10 @@ branch.<name>.rebase::
765 instead of merging the default branch from the default remote when
766 "git pull" is run. See "pull.rebase" for doing this in a non
767 branch-specific manner.
768 ++
769 + When preserve, also pass `--preserve-merges` along to 'git rebase'
770 + so that locally committed merge commits will not be flattened
771 + by running 'git pull'.
772 +
773 *NOTE*: this is a possibly dangerous operation; do *not* use
774 it unless you understand the implications (see linkgit:git-rebase[1]
@@ -1825,6 +1829,10 @@ pull.rebase::
1829 of merging the default branch from the default remote when "git
1830 pull" is run. See "branch.<name>.rebase" for setting this on a
1831 per-branch basis.
1832 ++
1833 + When preserve, also pass `--preserve-merges` along to 'git rebase'
1834 + so that locally committed merge commits will not be flattened
1835 + by running 'git pull'.
1836 +
1837 *NOTE*: this is a possibly dangerous operation; do *not* use
1838 it unless you understand the implications (see linkgit:git-rebase[1]
Documentation/git-pull.txt
+12 -6
@@ -102,12 +102,18 @@ include::merge-options.txt[]
102 :git-pull: 1
103
104 -r::
105 ---rebase::
106 - Rebase the current branch on top of the upstream branch after
107 - fetching. If there is a remote-tracking branch corresponding to
108 - the upstream branch and the upstream branch was rebased since last
109 - fetched, the rebase uses that information to avoid rebasing
110 - non-local changes.
105 +--rebase[=false|true|preserve]::
106 + When true, rebase the current branch on top of the upstream
107 + branch after fetching. If there is a remote-tracking branch
108 + corresponding to the upstream branch and the upstream branch
109 + was rebased since last fetched, the rebase uses that information
110 + to avoid rebasing non-local changes.
111 ++
112 +When preserve, also rebase the current branch on top of the upstream
113 +branch, but pass `--preserve-merges` along to `git rebase` so that
114 +locally created merge commits will not be flattened.
115 ++
116 +When false, merge the current branch into the upstream branch.
117 +
118 See `pull.rebase`, `branch.<name>.rebase` and `branch.autosetuprebase` in
119 linkgit:git-config[1] if you want to make `git pull` always use
git-pull.sh
+26 -5
@@ -4,7 +4,7 @@
4 #
5 # Fetch one or more remote refs and merge it/them into the current HEAD.
6
7 -USAGE='[-n | --no-stat] [--[no-]commit] [--[no-]squash] [--[no-]ff] [-s strategy]... [<fetch-options>] <repo> <head>...'
7 +USAGE='[-n | --no-stat] [--[no-]commit] [--[no-]squash] [--[no-]ff] [--[no-]rebase|--rebase=preserve] [-s strategy]... [<fetch-options>] <repo> <head>...'
8 LONG_USAGE='Fetch one or more remote refs and integrate it/them with the current HEAD.'
9 SUBDIRECTORY_OK=Yes
10 OPTIONS_SPEC=
@@ -38,15 +38,19 @@ Please, commit your changes before you can merge.")"
38 test -z "$(git ls-files -u)" || die_conflict
39 test -f "$GIT_DIR/MERGE_HEAD" && die_merge
40
41 +bool_or_string_config () {
42 + git config --bool "$1" 2>/dev/null || git config "$1"
43 +}
44 +
45 strategy_args= diffstat= no_commit= squash= no_ff= ff_only=
46 log_arg= verbosity= progress= recurse_submodules= verify_signatures=
43 -merge_args= edit=
47 +merge_args= edit= rebase_args=
48 curr_branch=$(git symbolic-ref -q HEAD)
49 curr_branch_short="${curr_branch#refs/heads/}"
46 -rebase=$(git config --bool branch.$curr_branch_short.rebase)
50 +rebase=$(bool_or_string_config branch.$curr_branch_short.rebase)
51 if test -z "$rebase"
52 then
49 - rebase=$(git config --bool pull.rebase)
53 + rebase=$(bool_or_string_config pull.rebase)
54 fi
55 dry_run=
56 while :
@@ -110,6 +114,9 @@ do
114 esac
115 merge_args="$merge_args$xx "
116 ;;
117 + -r=*|--r=*|--re=*|--reb=*|--reba=*|--rebas=*|--rebase=*)
118 + rebase="${1#*=}"
119 + ;;
120 -r|--r|--re|--reb|--reba|--rebas|--rebase)
121 rebase=true
122 ;;
@@ -145,6 +152,20 @@ do
152 shift
153 done
154
155 +case "$rebase" in
156 +preserve)
157 + rebase=true
158 + rebase_args=--preserve-merges
159 + ;;
160 +true|false|'')
161 + ;;
162 +*)
163 + echo "Invalid value for --rebase, should be true, false, or preserve"
164 + usage
165 + exit 1
166 + ;;
167 +esac
168 +
169 error_on_no_merge_candidates () {
170 exec >&2
171 for opt
@@ -292,7 +313,7 @@ fi
313 merge_name=$(git fmt-merge-msg $log_arg <"$GIT_DIR/FETCH_HEAD") || exit
314 case "$rebase" in
315 true)
295 - eval="git-rebase $diffstat $strategy_args $merge_args $verbosity"
316 + eval="git-rebase $diffstat $strategy_args $merge_args $rebase_args $verbosity"
317 eval="$eval --onto $merge_head ${oldremoteref:-$merge_head}"
318 ;;
319 *)
t/t5520-pull.sh
+89
@@ -148,6 +148,95 @@ test_expect_success 'branch.to-rebase.rebase should override pull.rebase' '
148 test new = $(git show HEAD:file2)
149 '
150
151 +# add a feature branch, keep-merge, that is merged into master, so the
152 +# test can try preserving the merge commit (or not) with various
153 +# --rebase flags/pull.rebase settings.
154 +test_expect_success 'preserve merge setup' '
155 + git reset --hard before-rebase &&
156 + git checkout -b keep-merge second^ &&
157 + test_commit file3 &&
158 + git checkout to-rebase &&
159 + git merge keep-merge &&
160 + git tag before-preserve-rebase
161 +'
162 +
163 +test_expect_success 'pull.rebase=false create a new merge commit' '
164 + git reset --hard before-preserve-rebase &&
165 + test_config pull.rebase false &&
166 + git pull . copy &&
167 + test $(git rev-parse HEAD^1) = $(git rev-parse before-preserve-rebase) &&
168 + test $(git rev-parse HEAD^2) = $(git rev-parse copy) &&
169 + test file3 = $(git show HEAD:file3.t)
170 +'
171 +
172 +test_expect_success 'pull.rebase=true flattens keep-merge' '
173 + git reset --hard before-preserve-rebase &&
174 + test_config pull.rebase true &&
175 + git pull . copy &&
176 + test $(git rev-parse HEAD^^) = $(git rev-parse copy) &&
177 + test file3 = $(git show HEAD:file3.t)
178 +'
179 +
180 +test_expect_success 'pull.rebase=1 is treated as true and flattens keep-merge' '
181 + git reset --hard before-preserve-rebase &&
182 + test_config pull.rebase 1 &&
183 + git pull . copy &&
184 + test $(git rev-parse HEAD^^) = $(git rev-parse copy) &&
185 + test file3 = $(git show HEAD:file3.t)
186 +'
187 +
188 +test_expect_success 'pull.rebase=preserve rebases and merges keep-merge' '
189 + git reset --hard before-preserve-rebase &&
190 + test_config pull.rebase preserve &&
191 + git pull . copy &&
192 + test $(git rev-parse HEAD^^) = $(git rev-parse copy) &&
193 + test $(git rev-parse HEAD^2) = $(git rev-parse keep-merge)
194 +'
195 +
196 +test_expect_success 'pull.rebase=invalid fails' '
197 + git reset --hard before-preserve-rebase &&
198 + test_config pull.rebase invalid &&
199 + ! git pull . copy
200 +'
201 +
202 +test_expect_success '--rebase=false create a new merge commit' '
203 + git reset --hard before-preserve-rebase &&
204 + test_config pull.rebase true &&
205 + git pull --rebase=false . copy &&
206 + test $(git rev-parse HEAD^1) = $(git rev-parse before-preserve-rebase) &&
207 + test $(git rev-parse HEAD^2) = $(git rev-parse copy) &&
208 + test file3 = $(git show HEAD:file3.t)
209 +'
210 +
211 +test_expect_success '--rebase=true rebases and flattens keep-merge' '
212 + git reset --hard before-preserve-rebase &&
213 + test_config pull.rebase preserve &&
214 + git pull --rebase=true . copy &&
215 + test $(git rev-parse HEAD^^) = $(git rev-parse copy) &&
216 + test file3 = $(git show HEAD:file3.t)
217 +'
218 +
219 +test_expect_success '--rebase=preserve rebases and merges keep-merge' '
220 + git reset --hard before-preserve-rebase &&
221 + test_config pull.rebase true &&
222 + git pull --rebase=preserve . copy &&
223 + test $(git rev-parse HEAD^^) = $(git rev-parse copy) &&
224 + test $(git rev-parse HEAD^2) = $(git rev-parse keep-merge)
225 +'
226 +
227 +test_expect_success '--rebase=invalid fails' '
228 + git reset --hard before-preserve-rebase &&
229 + ! git pull --rebase=invalid . copy
230 +'
231 +
232 +test_expect_success '--rebase overrides pull.rebase=preserve and flattens keep-merge' '
233 + git reset --hard before-preserve-rebase &&
234 + test_config pull.rebase preserve &&
235 + git pull --rebase . copy &&
236 + test $(git rev-parse HEAD^^) = $(git rev-parse copy) &&
237 + test file3 = $(git show HEAD:file3.t)
238 +'
239 +
240 test_expect_success '--rebase with rebased upstream' '
241
242 git remote add -f me . &&