Re: [PATCH v4 06/10] reset: introduce ability to skip updating HEAD

[Phillip Wood <phillip.wood123@gmail.com>]

Hi Patrick

On 10/06/2026 09:52, Patrick Steinhardt wrote:
> In a subsequent commit we'll introduce a new caller to
> `reset_working_tree()` that really only wants to update the index and
> working tree, without updating any references. Introduce a new flag that
> makes the caller opt in to updating HEAD and adapt all callers to set
> that flag.
> 
> Note that in a previous iteration we instead introduced a flag that made
> callers opt out of updating any references. This was somewhat awkward
> though because we already have the `UPDATE_ORIG_HEAD` flag, so the
> result was somewhat inconsistent.

Thanks for doing this. I've grepped for all the callers of reset_head() 
to confirm this patch adds RESET_HEAD_UPDATE_HEAD to them all.

I wonder if we should add a check for passing 
RESET_HEAD_UPDATE_ORIG_HEAD without RESET_HEAD_UPDATE_HEAD that calls 
BUG() as we don't support that. Everything else looks good.

Thanks

Phillip

> Suggested-by: Phillip Wood <phillip.wood123@gmail.com>
> Signed-off-by: Patrick Steinhardt <ps@pks.im>
> ---
>   builtin/rebase.c | 14 ++++++++++----
>   reset.c          |  6 ++++--
>   reset.h          |  9 ++++++---
>   sequencer.c      |  4 +++-
>   4 files changed, 23 insertions(+), 10 deletions(-)
> 
> diff --git a/builtin/rebase.c b/builtin/rebase.c
> index 06dcbaf5e8..10a306310c 100644
> --- a/builtin/rebase.c
> +++ b/builtin/rebase.c
> @@ -607,7 +607,8 @@ static int move_to_original_branch(struct rebase_options *opts)
>   	strbuf_addf(&head_reflog, "%s (finish): returning to %s",
>   		    opts->reflog_action, opts->head_name);
>   	ropts.branch = opts->head_name;
> -	ropts.flags = RESET_WORKING_TREE_REFS_ONLY;
> +	ropts.flags = RESET_WORKING_TREE_REFS_ONLY |
> +		      RESET_WORKING_TREE_UPDATE_HEAD;
>   	ropts.branch_msg = branch_reflog.buf;
>   	ropts.head_msg = head_reflog.buf;
>   	ret = reset_working_tree(the_repository, &ropts);
> @@ -693,6 +694,7 @@ static int run_am(struct rebase_options *opts)
>   		ropts.oid = &opts->orig_head->object.oid;
>   		ropts.branch = opts->head_name;
>   		ropts.default_reflog_action = opts->reflog_action;
> +		ropts.flags = RESET_WORKING_TREE_UPDATE_HEAD;
>   		reset_working_tree(the_repository, &ropts);
>   		error(_("\ngit encountered an error while preparing the "
>   			"patches to replay\n"
> @@ -862,7 +864,8 @@ static int checkout_up_to_date(struct rebase_options *options)
>   		    options->reflog_action, options->switch_to);
>   	ropts.oid = &options->orig_head->object.oid;
>   	ropts.branch = options->head_name;
> -	ropts.flags = RESET_WORKING_TREE_RUN_POST_CHECKOUT_HOOK;
> +	ropts.flags = RESET_WORKING_TREE_RUN_POST_CHECKOUT_HOOK |
> +		      RESET_WORKING_TREE_UPDATE_HEAD;
>   	if (!ropts.branch)
>   		ropts.flags |=  RESET_WORKING_TREE_DETACH;
>   	ropts.head_msg = buf.buf;
> @@ -1384,7 +1387,8 @@ int cmd_rebase(int argc,
>   
>   		rerere_clear(the_repository, &merge_rr);
>   		string_list_clear(&merge_rr, 1);
> -		ropts.flags = RESET_WORKING_TREE_HARD;
> +		ropts.flags = RESET_WORKING_TREE_HARD |
> +			      RESET_WORKING_TREE_UPDATE_HEAD;
>   		if (reset_working_tree(the_repository, &ropts) < 0)
>   			die(_("could not discard worktree changes"));
>   		remove_branch_state(the_repository, 0);
> @@ -1409,7 +1413,8 @@ int cmd_rebase(int argc,
>   		ropts.oid = &options.orig_head->object.oid;
>   		ropts.head_msg = head_msg.buf;
>   		ropts.branch = options.head_name;
> -		ropts.flags = RESET_WORKING_TREE_HARD;
> +		ropts.flags = RESET_WORKING_TREE_HARD |
> +			      RESET_WORKING_TREE_UPDATE_HEAD;
>   		if (reset_working_tree(the_repository, &ropts) < 0)
>   			die(_("could not move back to %s"),
>   			    oid_to_hex(&options.orig_head->object.oid));
> @@ -1877,6 +1882,7 @@ int cmd_rebase(int argc,
>   	ropts.oid = &options.onto->object.oid;
>   	ropts.orig_head = &options.orig_head->object.oid;
>   	ropts.flags = RESET_WORKING_TREE_DETACH |
> +		      RESET_WORKING_TREE_UPDATE_HEAD |
>   		      RESET_WORKING_TREE_UPDATE_ORIG_HEAD |
>   		      RESET_WORKING_TREE_RUN_POST_CHECKOUT_HOOK;
>   	ropts.head_msg = msg.buf;
> diff --git a/reset.c b/reset.c
> index 99f2c1b012..3ac99a51c0 100644
> --- a/reset.c
> +++ b/reset.c
> @@ -92,6 +92,7 @@ int reset_working_tree(struct repository *r,
>   	const char *switch_to_branch = opts->branch;
>   	unsigned reset_hard = opts->flags & RESET_WORKING_TREE_HARD;
>   	unsigned refs_only = opts->flags & RESET_WORKING_TREE_REFS_ONLY;
> +	unsigned update_head = opts->flags & RESET_WORKING_TREE_UPDATE_HEAD;
>   	unsigned update_orig_head = opts->flags & RESET_WORKING_TREE_UPDATE_ORIG_HEAD;
>   	unsigned dry_run = opts->flags & RESET_WORKING_TREE_DRY_RUN;
>   	struct object_id *head = NULL, head_oid;
> @@ -129,7 +130,7 @@ int reset_working_tree(struct repository *r,
>   		oid = &head_oid;
>   
>   	if (refs_only) {
> -		if (!dry_run)
> +		if (update_head)
>   			return update_refs(r, opts, oid, head);
>   		return 0;
>   	}
> @@ -197,7 +198,8 @@ int reset_working_tree(struct repository *r,
>   		goto leave_reset_head;
>   	}
>   
> -	if (oid != &head_oid || update_orig_head || switch_to_branch)
> +	if (update_head &&
> +	    (oid != &head_oid || update_orig_head || switch_to_branch))
>   		ret = update_refs(r, opts, oid, head);
>   
>   leave_reset_head:
> diff --git a/reset.h b/reset.h
> index 898e4a1e95..38b2891b53 100644
> --- a/reset.h
> +++ b/reset.h
> @@ -19,14 +19,17 @@ enum reset_working_tree_flags {
>   	/* Only update refs, do not touch the worktree */
>   	RESET_WORKING_TREE_REFS_ONLY = (1 << 3),
>   
> -	/* Update ORIG_HEAD as well as HEAD */
> -	RESET_WORKING_TREE_UPDATE_ORIG_HEAD = (1 << 4),
> +	/* Update HEAD */
> +	RESET_WORKING_TREE_UPDATE_HEAD = (1 << 4),
> +
> +	/* Update ORIG_HEAD */
> +	RESET_WORKING_TREE_UPDATE_ORIG_HEAD = (1 << 5),
>   
>   	/*
>   	 * Perform a dry-run by performing the operation without updating
>   	 * any user-visible state.
>   	 */
> -	RESET_WORKING_TREE_DRY_RUN = (1 << 5),
> +	RESET_WORKING_TREE_DRY_RUN = (1 << 6),
>   };
>   
>   struct reset_working_tree_options {
> diff --git a/sequencer.c b/sequencer.c
> index 4efe831178..e905b1b2d9 100644
> --- a/sequencer.c
> +++ b/sequencer.c
> @@ -4678,7 +4678,8 @@ static void create_autostash_internal(struct repository *r,
>   	    has_uncommitted_changes(r, 1)) {
>   		struct child_process stash = CHILD_PROCESS_INIT;
>   		struct reset_working_tree_options ropts = {
> -			.flags = RESET_WORKING_TREE_HARD,
> +			.flags = RESET_WORKING_TREE_HARD |
> +				 RESET_WORKING_TREE_UPDATE_HEAD,
>   		};
>   		struct object_id oid;
>   
> @@ -4873,6 +4874,7 @@ static int checkout_onto(struct repository *r, struct replay_opts *opts,
>   		.oid = onto,
>   		.orig_head = orig_head,
>   		.flags = RESET_WORKING_TREE_DETACH |
> +			 RESET_WORKING_TREE_UPDATE_HEAD |
>   			 RESET_WORKING_TREE_UPDATE_ORIG_HEAD |
>   			 RESET_WORKING_TREE_RUN_POST_CHECKOUT_HOOK,
>   		.head_msg = reflog_message(opts, "start", "checkout %s",
>