Subject: Re: [PATCH] sequencer: handle rebase-merge for "onto" message

From: Junio C Hamano <[email-masked]>
Date: Thu, 21 Nov 2019 09:16:03 +0900

Danh Doan <[email-masked]> writes:

> Anyway, when reading their patch, I discovered a problem with
> git rebase --rebase-merges when its message is onto.
>
> Here is a patch to fix it.
>
> I applied Dscho's patches over my dd/sequencer-utf8 then writing this
> patch, in case you have problem applying it.
>
> The context for the diff is coming from Dscho's patches.

Thanks.  While technically this is independent from the "safer
rebase-merges labels" topic (specifically its preparation step),
in the larger picture, this too is to ensure we do not use a wrong
string as a label ;-), so I'll queue it on top of those two patches,
just like how you developed.

Thanks.

> -------8<--------------------
> From 48205889b404b82baa4b30c2eedd52243c349e3e Mon Sep 17 00:00:00 2001
> From: Doan Tran Cong Danh <[email-masked]>
> Date: Mon, 18 Nov 2019 18:02:05 +0700
> Subject: [PATCH] sequencer: handle rebase-merge for "onto" message
>
> In order to work correctly, git-rebase --rebase-merges needs to make
> initial todo list with unique labels.
>
> Those unique labels is being handled by employing a hashmap and
> suffixing an unique number if any duplicate is found.
>
> But we forgat that beside of those labels for side branches,
> we also make a special label `onto' for our so-called new-base.
>
> In a special case that any of those labels for side branches named
> `onto', git will run into trouble.
>
> Correct it.
>
> Signed-off-by: Doan Tran Cong Danh <[email-masked]>
> ---
>  sequencer.c              |  5 +++++
>  t/t3430-rebase-merges.sh | 21 +++++++++++++++++++++
>  2 files changed, 26 insertions(+)
>
> diff --git a/sequencer.c b/sequencer.c
> index 350045b1b4..fc81e43f0f 100644
> --- a/sequencer.c
> +++ b/sequencer.c
> @@ -4569,10 +4569,15 @@ static int make_script_with_merges(struct pretty_print_context *pp,
>  	strbuf_init(&state.buf, 32);
>  
>  	if (revs->cmdline.nr && (revs->cmdline.rev[0].flags & BOTTOM)) {
> +		struct labels_entry *onto_label_entry;
>  		struct object_id *oid = &revs->cmdline.rev[0].item->oid;
>  		FLEX_ALLOC_STR(entry, string, "onto");
>  		oidcpy(&entry->entry.oid, oid);
>  		oidmap_put(&state.commit2label, entry);
> +
> +		FLEX_ALLOC_STR(onto_label_entry, label, "onto");
> +		hashmap_entry_init(&onto_label_entry->entry, strihash("onto"));
> +		hashmap_add(&state.labels, &onto_label_entry->entry);
>  	}
>  
>  	/*
> diff --git a/t/t3430-rebase-merges.sh b/t/t3430-rebase-merges.sh
> index f728aba995..4e2c0ede51 100755
> --- a/t/t3430-rebase-merges.sh
> +++ b/t/t3430-rebase-merges.sh
> @@ -474,4 +474,25 @@ test_expect_success '--rebase-merges with commit that can generate bad character
>  	git rebase --rebase-merges --force-rebase E
>  '
>  
> +test_expect_success '--rebase-merges with message matched with onto label' '
> +	git checkout -b onto-label E &&
> +	git merge -m onto G &&
> +	git rebase --rebase-merges --force-rebase E &&
> +	test_cmp_graph <<-\EOF
> +	*   onto
> +	|\
> +	| * G
> +	| * F
> +	* |   E
> +	|\ \
> +	| * | B
> +	* | | D
> +	| |/
> +	|/|
> +	* | C
> +	|/
> +	* A
> +	EOF
> +'
> +
>  test_done