Subject: Re: [PATCH] rebase: ignore non-branch update-refs

From: Phillip Wood <[email-masked]>
Date: Thu, 7 May 2026 17:08:24 +0100

Hi Abhinav

On 06/05/2026 03:39, [email-masked] wrote:
> From: Abhinav Gupta <[email-masked]>
> 
> The following Git configuration breaks git rebase --update-refs:
> 
>      [rebase]
>          instructionFormat = %s%d
> 
> The '%d' format requests all available decorations for a commit,
> filling the global decoration table with all of them,
> which --update-refs then uses to populate 'update-ref' instructions
> in the rebase todo list.
> 
> Specifically, this results in the following instruction:
> 
>      update-ref HEAD
> 
> The todo parser then rejects the instruction:
> 
>      error: update-ref requires a fully qualified refname e.g. refs/heads/HEAD
>      error: invalid line 3: update-ref HEAD
> 
> To fix, ignore decorations that are not local branches
> when scanning through the table.

Thanks for the clear explanation, the solution makes sense

> diff --git a/t/t3404-rebase-interactive.sh b/t/t3404-rebase-interactive.sh
> index 3e44562afa..d58236f0eb 100755
> --- a/t/t3404-rebase-interactive.sh
> +++ b/t/t3404-rebase-interactive.sh
> @@ -1960,6 +1960,28 @@ test_expect_success '--update-refs adds commands with --rebase-merges' '
>   	)
>   '
>   
> +test_expect_success '--update-refs ignores non-branch decorations' '
> +	test_when_finished "git branch -D update-refs" &&
> +	test_when_finished "git branch -D third" &&

I'm not sure that we really need to create this branch in the first
place. We already create update-refs from no-conflict-branch so we can
check that no-conflict-branch appears and update-refs does not. In
addition to checking that HEAD does not appear we should also check that
we don't try to update any tags (HEAD matches tag M). I think the
simplest way is to check the output of "grep ^update-ref todo" so we'd
have

test_expect_success '--update-refs ignores non-branch decorations' '
	test_when_finished "git branch -D update-refs" &&
	test_when_finished "git checkout primary" &&
	git checkout -B update-refs no-conflict-branch &&
	(
		set_cat_todo_editor &&

		# rebase.instructionFormat=%d loads normal log decorations before
		# --update-refs adds its branch placeholders so we must ignore
		# all non-local decorations.
		test_must_fail git -c rebase.instructionFormat="%s%d" \
			rebase -i --update-refs HEAD^ >todo
	) &&
	grep ^update-ref todo >actual &&
	test_write_lines "update-ref refs/heads/no-conflict-branch" >expect &&
	test_cmp expect actual
'

Thanks for working on this

Phillip

> +	test_when_finished "git checkout primary" &&
> +	git checkout -B update-refs no-conflict-branch &&
> +	git branch -f third HEAD~1 &&
> +	(
> +		set_cat_todo_editor &&
> +
> +		# rebase.instructionFormat=%d loads normal log decorations before
> +		# --update-refs adds its branch placeholders.
> +		# The placeholder scan must still ignore symbolic decorations,
> +		# because "update-ref HEAD" is not a valid branch update.
> +		test_must_fail git -c rebase.instructionFormat="%s%d" \
> +			rebase -i --update-refs primary >todo &&
> +
> +		test_grep "^update-ref refs/heads/third$" todo &&
> +		test_grep ! "^update-ref refs/heads/update-refs$" todo &&
> +		test_grep ! "^update-ref HEAD$" todo
> +	)
> +'
> +
>   test_expect_success '--update-refs updates refs correctly' '
>   	git checkout -B update-refs no-conflict-branch &&
>   	git branch -f base HEAD~4 &&
> 
> base-commit: 94f057755b7941b321fd11fec1b2e3ca5313a4e0