Subject: Re: [PATCH 1/1] refs.c: fix -Wsign-compare warnings

From: Junio C Hamano <[email-masked]>
Date: Sat, 08 Feb 2025 14:07:46 -0800

Moumita <[email-masked]> writes:

> Remove DISABLE_SIGN_COMPARE_WARNINGS from refs.c and fix integer
> comparison issues that caused -Wsign-compare warnings.
>
> Tested using `make DEVELOPER=1` and `make t` to ensure correctness.
> ---
>  refs.c | 11 ++++++-----
>  1 file changed, 6 insertions(+), 5 deletions(-)

I think this is wrong.

The string-list structure is screwed up in its use of types.

The alloc/nr pair to keep track of the number and insert index of
the elements were updated to size_t in 2022 but that change was
incomplete.  The API function string_list_find_insert_index() that
returns the index into list still return "int", and that is what
needs to be corrected, no?

> diff --git a/refs.c b/refs.c
> index 37b8cfb90c..e5cb7acfbe 100644
> --- a/refs.c
> +++ b/refs.c
> @@ -3,7 +3,7 @@
>   */
>  
>  #define USE_THE_REPOSITORY_VARIABLE
> -#define DISABLE_SIGN_COMPARE_WARNINGS
> +
>  
>  #include "git-compat-util.h"
>  #include "advice.h"
> @@ -1652,7 +1652,7 @@ const char *find_descendant_ref(const char *dirname,
>  	 * slash) and is not in skip, then we have a conflict.
>  	 */
>  	for (pos = string_list_find_insert_index(extras, dirname, 0);
> -	     pos < extras->nr; pos++) {
> +	 (size_t)pos < extras->nr; pos++) {
>  		const char *extra_refname = extras->items[pos].string;

> @@ -2304,7 +2304,8 @@ static int run_transaction_hook(struct ref_transaction *transaction,
>  	struct child_process proc = CHILD_PROCESS_INIT;
>  	struct strbuf buf = STRBUF_INIT;
>  	const char *hook;
> -	int ret = 0, i;
> +	int ret = 0;
> +	size_t i ;

This may be OK, as .nr is of size_t.

>  	hook = find_hook(transaction->ref_store->repo, "reference-transaction");
>  	if (!hook)
> @@ -2635,9 +2636,9 @@ void ref_transaction_for_each_queued_update(struct ref_transaction *transaction,
>  					    ref_transaction_for_each_queued_update_fn cb,
>  					    void *cb_data)
>  {
> -	int i;
> +	size_t i;
>  
> -	for (i = 0; i < transaction->nr; i++) {
> +	for ( i = 0; i < transaction->nr; i++) {

It is also wrong to add SP there.

>  		struct ref_update *update = transaction->updates[i];
>  
>  		cb(update->refname,