Re: [PATCH v12 3/6] branch: prepare delete_branches for a bulk caller

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

Hi Harald

On 03/06/2026 10:04, Harald Nordgren via GitGitGadget wrote:
> From: Harald Nordgren <haraldnordgren@gmail.com>
> 
> Add no_head_fallback and dry_run flags to delete_branches() so a
> bulk caller (the upcoming --prune-merged) can ask strictly about
> merged-into-upstream without a silent fallback to HEAD, and
> rehearse deletions with the same "Would delete branch ..." wording
> as the live run. Existing callers pass 0 for both and keep current
> behavior.
> 
> When no_head_fallback is set, head_rev stays NULL through to
> branch_merged(), whose "merged to X but not yet merged to HEAD"
> reminder otherwise compares against HEAD. For the bulk caller
> every candidate is known to have an upstream, so HEAD is
> irrelevant. Guard the block on head_rev so the NULL case skips
> it instead of treating "NULL != reference_rev" as "diverges from
> HEAD" and emitting a spurious warning.

Same comment as the last patch - use a flags argument rather than lots 
of individual booleans that make the call sites hard to read.

Thanks

Phillip

> Signed-off-by: Harald Nordgren <haraldnordgren@gmail.com>
> ---
>   builtin/branch.c | 27 +++++++++++++++++++--------
>   1 file changed, 19 insertions(+), 8 deletions(-)
> 
> diff --git a/builtin/branch.c b/builtin/branch.c
> index 93d8eae891..09afdd9257 100644
> --- a/builtin/branch.c
> +++ b/builtin/branch.c
> @@ -169,10 +169,13 @@ static int branch_merged(int kind, const char *name,
>   	 * upstream, if any, otherwise with HEAD", we should just
>   	 * return the result of the repo_in_merge_bases() above without
>   	 * any of the following code, but during the transition period,
> -	 * a gentle reminder is in order.
> +	 * a gentle reminder is in order.  Callers that opt out of the
> +	 * HEAD fallback by passing head_rev=NULL are not interested in
> +	 * the reminder either: they have already established that the
> +	 * branch has an upstream, so HEAD is irrelevant to the decision.
>   	 */
> -	if (head_rev != reference_rev) {
> -		int expect = head_rev ? repo_in_merge_bases(the_repository, rev, head_rev) : 0;
> +	if (head_rev && head_rev != reference_rev) {
> +		int expect = repo_in_merge_bases(the_repository, rev, head_rev);
>   		if (expect < 0)
>   			exit(128);
>   		if (expect == merged)
> @@ -225,7 +228,8 @@ static void delete_branch_config(const char *branchname)
>   }
>   
>   static int delete_branches(int argc, const char **argv, int force, int kinds,
> -			   int quiet, int warn_only)
> +			   int quiet, int warn_only, int no_head_fallback,
> +			   int dry_run)
>   {
>   	struct commit *head_rev = NULL;
>   	struct object_id oid;
> @@ -259,7 +263,7 @@ static int delete_branches(int argc, const char **argv, int force, int kinds,
>   	}
>   	branch_name_pos = strcspn(fmt, "%");
>   
> -	if (!force)
> +	if (!force && !no_head_fallback)
>   		head_rev = lookup_commit_reference(the_repository, &head_oid);
>   
>   	for (i = 0; i < argc; i++, strbuf_reset(&bname)) {
> @@ -330,13 +334,20 @@ static int delete_branches(int argc, const char **argv, int force, int kinds,
>   		free(target);
>   	}
>   
> -	if (refs_delete_refs(get_main_ref_store(the_repository), NULL, &refs_to_delete, REF_NO_DEREF))
> +	if (!dry_run &&
> +	    refs_delete_refs(get_main_ref_store(the_repository), NULL, &refs_to_delete, REF_NO_DEREF))
>   		ret = 1;
>   
>   	for_each_string_list_item(item, &refs_to_delete) {
>   		char *describe_ref = item->util;
>   		char *name = item->string;
> -		if (!refs_ref_exists(get_main_ref_store(the_repository), name)) {
> +		if (dry_run) {
> +			if (!quiet)
> +				printf(remote_branch
> +					? _("Would delete remote-tracking branch %s (was %s).\n")
> +					: _("Would delete branch %s (was %s).\n"),
> +					name + branch_name_pos, describe_ref);
> +		} else if (!refs_ref_exists(get_main_ref_store(the_repository), name)) {
>   			char *refname = name + branch_name_pos;
>   			if (!quiet)
>   				printf(remote_branch
> @@ -1003,7 +1014,7 @@ int cmd_branch(int argc,
>   		if (!argc)
>   			die(_("branch name required"));
>   		ret = delete_branches(argc, argv, delete > 1, filter.kind,
> -				      quiet, 0);
> +				      quiet, 0, 0, 0);
>   		goto out;
>   	} else if (show_current) {
>   		print_current_branch_name();