From: Phillip Wood <phillip.wood123@gmail.com>
To: Denton Liu <liu.denton@gmail.com>,
Git Mailing List <git@vger.kernel.org>
Cc: "Eric Sunshine" <sunshine@sunshineco.com>,
"Junio C Hamano" <gitster@pobox.com>,
"Ævar Arnfjörð Bjarmason" <avarab@gmail.com>,
"Johannes Schindelin" <Johannes.Schindelin@gmx.de>,
"Johannes Sixt" <j6t@kdbg.org>,
"SZEDER Gábor" <szeder.dev@gmail.com>
Subject: Re: [PATCH v6 4/6] rebase: fast-forward --onto in more cases
Date: Wed, 17 Apr 2019 20:59:09 +0100 [thread overview]
Message-ID: <da5b0efb-1245-7f34-be4e-4e936e9d1d20@gmail.com> (raw)
In-Reply-To: <2559ab54a2c6e5544595e0d66a431e249bf73ca8.1555523176.git.liu.denton@gmail.com>
Hi Denton
On 17/04/2019 19:01, Denton Liu wrote:
> Before, when we had the following graph,
>
> A---B---C (master)
> \
> D (side)
>
> running 'git rebase --onto master... master side' would result in D
> being always rebased, no matter what. However, the desired behavior is
> that rebase should notice that this is fast-forwardable and do that
> instead.
>
> Add detection to `can_fast_forward` so that this case can be detected
> and a fast-forward will be performed. First of all, rewrite the function
> to use gotos which simplifies the logic. Next, since the
>
> options.upstream &&
> !oidcmp(&options.upstream->object.oid, &options.onto->object.oid)
>
> conditions were removed in `cmd_rebase`, we reintroduce a substitute in
> `can_fast_forward`. In particular, checking the merge bases of
> `upstream` and `head` fixes a failing case in t3416.
>
> The abbreviated graph for t3416 is as follows:
>
> F---G topic
> /
> A---B---C---D---E master
>
> and the failing command was
>
> git rebase --onto master...topic F topic
>
> Before, Git would see that there was one merge base (C), and the merge
> and onto were the same so it would incorrectly return 1, indicating that
> we could fast-forward. This would cause the rebased graph to be 'ABCFG'
> when we were expecting 'ABCG'.
>
> With the additional logic, we detect that upstream and head's merge base
> is F. Since onto isn't F, it means we're not rebasing the full set of
> commits from master..topic. Since we're excluding some commits, a
> fast-forward cannot be performed and so we correctly return 0.
>
> Add '-f' to test cases that failed as a result of this change because
> they were not expecting a fast-forward so that a rebase is forced.
>
> While we're at it, remove a trailing whitespace from rebase.c.
>
> Helped-by: Phillip Wood <phillip.wood@dunelm.org.uk>
> Signed-off-by: Denton Liu <liu.denton@gmail.com>
> ---
> builtin/rebase.c | 28 +++++++++++++++++++---------
> t/t3400-rebase.sh | 2 +-
> t/t3404-rebase-interactive.sh | 2 +-
> t/t3432-rebase-fast-forward.sh | 4 ++--
> 4 files changed, 23 insertions(+), 13 deletions(-)
>
> diff --git a/builtin/rebase.c b/builtin/rebase.c
> index de10b6f5ad..f5aca1eee0 100644
> --- a/builtin/rebase.c
> +++ b/builtin/rebase.c
> @@ -895,8 +895,8 @@ 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 object_id *head_oid, struct object_id *merge_base)
> {
> struct commit *head = lookup_commit(the_repository, head_oid);
> struct commit_list *merge_bases = NULL;
> @@ -915,6 +915,18 @@ static int can_fast_forward(struct commit *onto, struct object_id *head_oid,
> if (!oideq(merge_base, &onto->object.oid))
> 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;
> + }
Thanks for changing the ifs in this patch and the previous one, I find
it much easier to follow now. Just one style nit (probably not worth a
reroll) - we don't put braces around a single conditional statement like
this unless another branch of the same if requires them (then all
branches should have them).
Best Wishes
Phillip
> +
> + if (!oideq(&onto->object.oid, &merge_bases->item->object.oid))
> + goto done;
> +
> res = 1;
>
> done:
> @@ -1688,13 +1700,11 @@ 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.
> + * but this should be done if this is not 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.orig_head,
> + &merge_base) &&
> + !is_interactive(&options) && !options.restrict_revision) {
> int flag;
>
> if (!(options.flags & REBASE_FORCE)) {
> @@ -1788,7 +1798,7 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
> strbuf_addf(&msg, "%s: checkout %s",
> getenv(GIT_REFLOG_ACTION_ENVIRONMENT), options.onto_name);
> if (reset_head(&options.onto->object.oid, "checkout", NULL,
> - RESET_HEAD_DETACH | RESET_ORIG_HEAD |
> + RESET_HEAD_DETACH | RESET_ORIG_HEAD |
> RESET_HEAD_RUN_POST_CHECKOUT_HOOK,
> NULL, msg.buf))
> die(_("Could not detach HEAD"));
> diff --git a/t/t3400-rebase.sh b/t/t3400-rebase.sh
> index 460d0523be..604d624ff8 100755
> --- a/t/t3400-rebase.sh
> +++ b/t/t3400-rebase.sh
> @@ -295,7 +295,7 @@ test_expect_success 'rebase--am.sh 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
> )
> diff --git a/t/t3404-rebase-interactive.sh b/t/t3404-rebase-interactive.sh
> index b60b11f9f2..f054186cc7 100755
> --- a/t/t3404-rebase-interactive.sh
> +++ b/t/t3404-rebase-interactive.sh
> @@ -1066,7 +1066,7 @@ 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
> '
> diff --git a/t/t3432-rebase-fast-forward.sh b/t/t3432-rebase-fast-forward.sh
> index 4f04d67fd7..d0e5b1f3e6 100755
> --- a/t/t3432-rebase-fast-forward.sh
> +++ b/t/t3432-rebase-fast-forward.sh
> @@ -64,9 +64,9 @@ test_expect_success 'add work to upstream' '
> changes='our and their changes'
> test_rebase_same_head success --onto B B
> test_rebase_same_head success --onto B... B
> -test_rebase_same_head failure --onto master... master
> +test_rebase_same_head success --onto master... master
> test_rebase_same_head failure --fork-point --onto B B
> test_rebase_same_head failure --fork-point --onto B... B
> -test_rebase_same_head failure --fork-point --onto master... master
> +test_rebase_same_head success --fork-point --onto master... master
>
> test_done
>
next prev parent reply other threads:[~2019-04-17 19:59 UTC|newest]
Thread overview: 123+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-23 15:25 [PATCH 0/3] rebase: learn --keep-base Denton Liu
2019-03-23 15:25 ` [PATCH 1/3] rebase: teach rebase --keep-base Denton Liu
2019-03-24 3:46 ` Eric Sunshine
2019-03-24 13:20 ` Junio C Hamano
2019-03-25 0:06 ` Denton Liu
2019-03-25 5:41 ` Denton Liu
2019-04-01 10:45 ` Junio C Hamano
2019-03-24 13:37 ` Junio C Hamano
2019-03-25 5:47 ` Denton Liu
2019-03-25 18:50 ` Johannes Schindelin
2019-03-25 19:29 ` Denton Liu
2019-03-26 13:27 ` Johannes Schindelin
2019-03-23 15:25 ` [PATCH 2/3] t3416: test " Denton Liu
2019-03-23 15:25 ` [PATCH 3/3] git-rebase.txt: document --keep-base option Denton Liu
2019-03-24 13:15 ` [PATCH 0/3] rebase: learn --keep-base Junio C Hamano
2019-03-25 0:04 ` Denton Liu
2019-04-01 10:45 ` Junio C Hamano
2019-03-26 14:35 ` Ævar Arnfjörð Bjarmason
2019-03-26 17:50 ` Denton Liu
2019-03-26 20:35 ` Ævar Arnfjörð Bjarmason
2019-03-26 21:30 ` Denton Liu
2019-03-27 15:39 ` Ævar Arnfjörð Bjarmason
2019-03-28 22:17 ` [PATCH v2] rebase: teach rebase --keep-base Denton Liu
2019-03-28 23:13 ` Ævar Arnfjörð Bjarmason
2019-03-29 15:47 ` Johannes Schindelin
2019-03-29 17:52 ` Denton Liu
2019-04-01 10:46 ` Junio C Hamano
2019-04-01 20:51 ` [PATCH v3 0/4] " Denton Liu
2019-04-01 20:51 ` [PATCH v3 1/4] t3431: add rebase --fork-point tests Denton Liu
2019-04-04 20:28 ` Denton Liu
2019-04-05 11:15 ` SZEDER Gábor
2019-04-08 4:38 ` Junio C Hamano
2019-04-05 14:55 ` Johannes Schindelin
2019-04-05 17:25 ` Denton Liu
2019-04-05 17:51 ` Johannes Sixt
2019-04-05 18:51 ` Johannes Schindelin
2019-04-05 20:19 ` Johannes Schindelin
2019-04-05 21:10 ` SZEDER Gábor
2019-04-01 20:51 ` [PATCH v3 2/4] t3432: test rebase fast-forward behavior Denton Liu
2019-04-01 20:52 ` [PATCH v3 3/4] rebase: fast-forward --onto in more cases Denton Liu
2019-04-02 1:25 ` Junio C Hamano
2019-04-02 1:48 ` Junio C Hamano
2019-04-02 4:44 ` Denton Liu
2019-04-01 20:52 ` [PATCH v3 4/4] rebase: teach rebase --keep-base Denton Liu
2019-04-05 21:39 ` [PATCH v4 0/4] " Denton Liu
2019-04-05 21:40 ` [PATCH v4 1/4] t3431: add rebase --fork-point tests Denton Liu
2019-04-05 21:40 ` [PATCH v4 2/4] t3432: test rebase fast-forward behavior Denton Liu
2019-04-05 21:40 ` [PATCH v4 3/4] rebase: fast-forward --onto in more cases Denton Liu
2019-04-05 21:40 ` [PATCH v4 4/4] rebase: teach rebase --keep-base Denton Liu
2019-04-15 22:29 ` [PATCH v5 0/5] " Denton Liu
2019-04-15 22:29 ` [PATCH v5 1/5] t3431: add rebase --fork-point tests Denton Liu
2019-04-15 22:29 ` [PATCH v5 2/5] t3432: test rebase fast-forward behavior Denton Liu
2019-04-15 22:29 ` [PATCH v5 3/5] rebase: fast-forward --onto in more cases Denton Liu
2019-04-16 6:26 ` Junio C Hamano
2019-04-16 13:59 ` Phillip Wood
2019-04-17 6:44 ` Denton Liu
2019-04-17 14:14 ` Phillip Wood
2019-04-19 17:08 ` Denton Liu
2019-04-15 22:29 ` [PATCH v5 4/5] rebase: fast-forward --fork-point " Denton Liu
2019-04-15 22:29 ` [PATCH v5 5/5] rebase: teach rebase --keep-base Denton Liu
2019-04-17 18:01 ` [PATCH v6 0/5] " Denton Liu
2019-04-17 18:01 ` [PATCH v6 1/6] t3431: add rebase --fork-point tests Denton Liu
2019-04-17 18:01 ` [PATCH v6 2/6] t3432: test rebase fast-forward behavior Denton Liu
2019-04-17 18:01 ` [PATCH v6 3/6] rebase: refactor can_fast_forward into goto tower Denton Liu
2019-04-17 18:01 ` [PATCH v6 4/6] rebase: fast-forward --onto in more cases Denton Liu
2019-04-17 19:59 ` Phillip Wood [this message]
2019-04-17 18:01 ` [PATCH v6 5/6] rebase: fast-forward --fork-point " Denton Liu
2019-04-17 18:01 ` [PATCH v6 6/6] rebase: teach rebase --keep-base Denton Liu
2019-04-21 8:11 ` [PATCH v7 0/6] rebase: learn --keep-base Denton Liu
2019-04-21 8:11 ` [PATCH v7 1/6] t3431: add rebase --fork-point tests Denton Liu
2019-04-23 23:12 ` Denton Liu
2019-04-21 8:11 ` [PATCH v7 2/6] t3432: test rebase fast-forward behavior Denton Liu
2019-04-21 8:11 ` [PATCH v7 3/6] rebase: refactor can_fast_forward into goto tower Denton Liu
2019-04-21 8:11 ` [PATCH v7 4/6] rebase: fast-forward --onto in more cases Denton Liu
2019-04-21 8:11 ` [PATCH v7 5/6] rebase: fast-forward --fork-point " Denton Liu
2019-04-21 8:11 ` [PATCH v7 6/6] rebase: teach rebase --keep-base Denton Liu
2019-05-08 0:12 ` [RFC WIP PATCH v8 00/13] learn --keep-base & more Ævar Arnfjörð Bjarmason
2019-05-08 3:57 ` Junio C Hamano
2019-07-19 19:14 ` Junio C Hamano
2019-07-19 21:01 ` Denton Liu
2019-08-25 9:11 ` [PATCH v9 0/9] rebase: learn --keep-base and improvements on fast-forward behaviour Denton Liu
2019-08-25 9:11 ` [PATCH v9 1/9] t3431: add rebase --fork-point tests Denton Liu
2019-08-25 9:12 ` [PATCH v9 2/9] t3432: test rebase fast-forward behavior Denton Liu
2019-08-25 9:12 ` [PATCH v9 3/9] t3432: distinguish "noop-same" v.s. "work-same" in "same head" tests Denton Liu
2019-08-25 9:12 ` [PATCH v9 4/9] t3432: test for --no-ff's interaction with fast-forward Denton Liu
2019-08-25 9:12 ` [PATCH v9 5/9] rebase: refactor can_fast_forward into goto tower Denton Liu
2019-08-25 13:17 ` Pratyush Yadav
2019-08-26 23:17 ` Denton Liu
2019-08-25 9:12 ` [PATCH v9 6/9] rebase: fast-forward --onto in more cases Denton Liu
2019-08-25 9:12 ` [PATCH v9 7/9] rebase: fast-forward --fork-point " Denton Liu
2019-08-25 9:12 ` [PATCH v9 8/9] rebase tests: test linear branch topology Denton Liu
2019-08-25 9:12 ` [PATCH v9 9/9] rebase: teach rebase --keep-base Denton Liu
2019-08-25 22:59 ` Philip Oakley
2019-08-26 19:37 ` [PATCH v9 0/9] rebase: learn --keep-base and improvements on fast-forward behaviour Junio C Hamano
2019-08-27 5:37 ` [PATCH v10 " Denton Liu
2019-08-27 5:37 ` [PATCH v10 1/9] t3431: add rebase --fork-point tests Denton Liu
2019-08-27 5:37 ` [PATCH v10 2/9] t3432: test rebase fast-forward behavior Denton Liu
2019-08-27 5:37 ` [PATCH v10 3/9] t3432: distinguish "noop-same" v.s. "work-same" in "same head" tests Denton Liu
2019-08-27 5:37 ` [PATCH v10 4/9] t3432: test for --no-ff's interaction with fast-forward Denton Liu
2019-08-27 8:11 ` SZEDER Gábor
2019-08-27 5:37 ` [PATCH v10 5/9] rebase: refactor can_fast_forward into goto tower Denton Liu
2019-08-27 5:37 ` [PATCH v10 6/9] rebase: fast-forward --onto in more cases Denton Liu
2019-08-27 5:38 ` [PATCH v10 7/9] rebase: fast-forward --fork-point " Denton Liu
2019-08-27 5:38 ` [PATCH v10 8/9] rebase tests: test linear branch topology Denton Liu
2019-08-27 5:38 ` [PATCH v10 9/9] rebase: teach rebase --keep-base Denton Liu
2019-05-08 0:12 ` [RFC WIP PATCH v8 01/13] t3431: add rebase --fork-point tests Ævar Arnfjörð Bjarmason
2019-05-08 0:12 ` [RFC WIP PATCH v8 02/13] t3432: test rebase fast-forward behavior Ævar Arnfjörð Bjarmason
2019-05-08 0:12 ` [RFC WIP PATCH v8 03/13] t3432: distinguish "noop-same" v.s. "work-same" in "same head" tests Ævar Arnfjörð Bjarmason
2019-05-08 0:12 ` [RFC WIP PATCH v8 04/13] t3432: test for --no-ff's interaction with fast-forward Ævar Arnfjörð Bjarmason
2019-05-08 0:12 ` [RFC WIP PATCH v8 05/13] rebase: refactor can_fast_forward into goto tower Ævar Arnfjörð Bjarmason
2019-05-08 0:12 ` [RFC WIP PATCH v8 06/13] rebase: fast-forward --onto in more cases Ævar Arnfjörð Bjarmason
2019-05-08 0:12 ` [RFC WIP PATCH v8 07/13] rebase: fast-forward --fork-point " Ævar Arnfjörð Bjarmason
2019-05-08 0:12 ` [RFC WIP PATCH v8 08/13] rebase: teach rebase --keep-base Ævar Arnfjörð Bjarmason
2019-05-08 0:12 ` [RFC WIP PATCH v8 09/13] rebase tests: test linear branch topology Ævar Arnfjörð Bjarmason
2019-05-08 0:12 ` [RFC WIP PATCH v8 10/13] rebase: don't rebase linear topology with --fork-point Ævar Arnfjörð Bjarmason
2019-05-08 0:12 ` [RFC WIP PATCH v8 11/13] rebase: eliminate side-effects from can_fast_forward() Ævar Arnfjörð Bjarmason
2019-05-17 21:16 ` Johannes Schindelin
2019-05-08 0:12 ` [RFC WIP PATCH v8 12/13] rebase: add a should_fast_forward() utility function Ævar Arnfjörð Bjarmason
2019-05-08 0:12 ` [RFC WIP PATCH v8 13/13] WIP: can_fast_forward() support for --preserve-merges and --rebase-merges Ævar Arnfjörð Bjarmason
2019-05-17 22:02 ` Johannes Schindelin
2019-04-06 19:44 ` [PATCH v3 0/4] rebase: teach rebase --keep-base Ævar Arnfjörð Bjarmason
2019-04-06 20:38 ` Denton Liu
2019-04-13 21:10 ` Ævar Arnfjörð Bjarmason
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