For convenience in scripts and aliases, add the option
--ff-only to only allow fast-forwards (and up-to-date,
despite the name).
Disallow combining --ff-only and --no-ff, since they
flatly contradict each other.
Allow all other options to be combined with --ff-only
(i.e. do not add any code to handle them specially),
including the following options:
* --strategy (one or more): As long as the chosen merge
strategy results in up-to-date or fast-forward, the
command will succeed.
* --squash: I cannot imagine why anyone would want to
squash commits only if fast-forward is possible, but I
also see no reason why it should not be allowed.
* --message: The message will always be ignored, but I see
no need to explicitly disallow providing a redundant message.
Acknowledgements: I did look at Yuval Kogman's earlier
patch (107768 in gmane), mainly as shortcut to find my
way in the code, but I did not copy anything directly.
Signed-off-by: Björn Gustavsson <bgustavsson@xxxxxxxxx>
---
Here is a re-roll of my previous patch with improvements
suggested by Junio's review. Compared to the previous version,
I have changed the following:
* The documentation now clearly states that up-to-date
is also allowed.
* The redundant and incorrect test to reject merge strategies
that do not allow fast-forward has been removed (along
with the corresponding test case).
* I have added some background on the design decisions to
the commit message.
* I have added two test cases to test --squash in combination
with --ff-only.
Documentation/merge-options.txt | 5 ++++
builtin-merge.c | 11 +++++++++-
git-pull.sh | 7 ++++-
t/t7600-merge.sh | 41 +++++++++++++++++++++++++++++++++++++++
4 files changed, 61 insertions(+), 3 deletions(-)
diff --git a/Documentation/merge-options.txt b/Documentation/merge-options.txt
index adadf8e..27a9a84 100644
--- a/Documentation/merge-options.txt
+++ b/Documentation/merge-options.txt
@@ -60,6 +60,11 @@
a fast-forward, only update the branch pointer. This is
the default behavior of git-merge.
+--ff-only::
+ Refuse to merge and exit with a non-zero status unless the
+ current `HEAD` is already up-to-date or the merge can be
+ resolved as a fast-forward.
+
-s <strategy>::
--strategy=<strategy>::
Use the given merge strategy; can be supplied more than
diff --git a/builtin-merge.c b/builtin-merge.c
index b6b8428..5e8c4b5 100644
--- a/builtin-merge.c
+++ b/builtin-merge.c
@@ -43,6 +43,7 @@ static const char * const builtin_merge_usage[] = {
static int show_diffstat = 1, option_log, squash;
static int option_commit = 1, allow_fast_forward = 1;
+static int fast_forward_only;
static int allow_trivial = 1, have_message;
static struct strbuf merge_msg;
static struct commit_list *remoteheads;
@@ -167,6 +168,8 @@ static struct option builtin_merge_options[] = {
"perform a commit if the merge succeeds (default)"),
OPT_BOOLEAN(0, "ff", &allow_fast_forward,
"allow fast forward (default)"),
+ OPT_BOOLEAN(0, "ff-only", &fast_forward_only,
+ "abort if fast forward is not possible"),
OPT_CALLBACK('s', "strategy", &use_strategies, "strategy",
"merge strategy to use", option_parse_strategy),
OPT_CALLBACK('m', "message", &merge_msg, "message",
@@ -874,6 +877,9 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
option_commit = 0;
}
+ if (!allow_fast_forward && fast_forward_only)
+ die("You cannot combine --no-ff with --ff-only.");
+
if (!argc)
usage_with_options(builtin_merge_usage,
builtin_merge_options);
@@ -1040,7 +1046,7 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
* only one common.
*/
refresh_cache(REFRESH_QUIET);
- if (allow_trivial) {
+ if (allow_trivial && !fast_forward_only) {
/* See if it is really trivial. */
git_committer_info(IDENT_ERROR_ON_NO_NAME);
printf("Trying really trivial in-index merge...\n");
@@ -1079,6 +1085,9 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
}
}
+ if (fast_forward_only)
+ die("Not possible to fast forward, aborting.");
+
/* We are going to make a new commit. */
git_committer_info(IDENT_ERROR_ON_NO_NAME);
diff --git a/git-pull.sh b/git-pull.sh
index fc78592..37f3d93 100755
--- a/git-pull.sh
+++ b/git-pull.sh
@@ -16,7 +16,8 @@ cd_to_toplevel
test -z "$(git ls-files -u)" ||
die "You are in the middle of a conflicted merge."
-strategy_args= diffstat= no_commit= squash= no_ff= log_arg= verbosity=
+strategy_args= diffstat= no_commit= squash= no_ff= ff_only=
+log_arg= verbosity=
curr_branch=$(git symbolic-ref -q HEAD)
curr_branch_short=$(echo "$curr_branch" | sed "s|refs/heads/||")
rebase=$(git config --bool branch.$curr_branch_short.rebase)
@@ -45,6 +46,8 @@ do
no_ff=--ff ;;
--no-ff)
no_ff=--no-ff ;;
+ --ff-only)
+ ff_only=--ff-only ;;
-s=*|--s=*|--st=*|--str=*|--stra=*|--strat=*|--strate=*|\
--strateg=*|--strategy=*|\
-s|--s|--st|--str|--stra|--strat|--strate|--strateg|--strategy)
@@ -215,5 +218,5 @@ merge_name=$(git fmt-merge-msg $log_arg <"$GIT_DIR/FETCH_HEAD") || exit
test true = "$rebase" &&
exec git-rebase $diffstat $strategy_args --onto $merge_head \
${oldremoteref:-$merge_head}
-exec git-merge $diffstat $no_commit $squash $no_ff $log_arg $strategy_args \
+exec git-merge $diffstat $no_commit $squash $no_ff $ff_only $log_arg $strategy_args \
"$merge_name" HEAD $merge_head $verbosity
diff --git a/t/t7600-merge.sh b/t/t7600-merge.sh
index e5b210b..57f6d2b 100755
--- a/t/t7600-merge.sh
+++ b/t/t7600-merge.sh
@@ -243,6 +243,16 @@ test_expect_success 'merge c0 with c1' '
test_debug 'gitk --all'
+test_expect_success 'merge c0 with c1 with --ff-only' '
+ git reset --hard c0 &&
+ git merge --ff-only c1 &&
+ git merge --ff-only HEAD c0 c1 &&
+ verify_merge file result.1 &&
+ verify_head "$c1"
+'
+
+test_debug 'gitk --all'
+
test_expect_success 'merge c1 with c2' '
git reset --hard c1 &&
test_tick &&
@@ -263,6 +273,14 @@ test_expect_success 'merge c1 with c2 and c3' '
test_debug 'gitk --all'
+test_expect_success 'failing merges with --ff-only' '
+ git reset --hard c1 &&
+ test_tick &&
+ test_must_fail git merge --ff-only c2 &&
+ test_must_fail git merge --ff-only c3 &&
+ test_must_fail git merge --ff-only c2 c3
+'
+
test_expect_success 'merge c0 with c1 (no-commit)' '
git reset --hard c0 &&
git merge --no-commit c1 &&
@@ -303,6 +321,17 @@ test_expect_success 'merge c0 with c1 (squash)' '
test_debug 'gitk --all'
+test_expect_success 'merge c0 with c1 (squash, ff-only)' '
+ git reset --hard c0 &&
+ git merge --squash --ff-only c1 &&
+ verify_merge file result.1 &&
+ verify_head $c0 &&
+ verify_no_mergehead &&
+ verify_diff squash.1 .git/SQUASH_MSG "[OOPS] bad squash message"
+'
+
+test_debug 'gitk --all'
+
test_expect_success 'merge c1 with c2 (squash)' '
git reset --hard c1 &&
git merge --squash c2 &&
@@ -314,6 +343,13 @@ test_expect_success 'merge c1 with c2 (squash)' '
test_debug 'gitk --all'
+test_expect_success 'unsuccesful merge of c1 with c2 (squash, ff-only)' '
+ git reset --hard c1 &&
+ test_must_fail git merge --squash --ff-only c2
+'
+
+test_debug 'gitk --all'
+
test_expect_success 'merge c1 with c2 and c3 (squash)' '
git reset --hard c1 &&
git merge --squash c2 c3 &&
@@ -432,6 +468,11 @@ test_expect_success 'combining --squash and --no-ff is refused' '
test_must_fail git merge --no-ff --squash c1
'
+test_expect_success 'combining --ff-only and --no-ff is refused' '
+ test_must_fail git merge --ff-only --no-ff c1 &&
+ test_must_fail git merge --no-ff --ff-only c1
+'
+
test_expect_success 'merge c0 with c1 (ff overrides no-ff)' '
git reset --hard c0 &&
git config branch.master.mergeoptions "--no-ff" &&
--
1.6.5.1.69.g36942
--
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