Re: [PATCH 21/21] config: fix sign comparison warnings

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

Hi Patrick

On 17/07/2025 11:49, Patrick Steinhardt wrote:
> There are a couple of -Wsign-compare warnings in "config.c":
> 
>    - `prepare_include_condition_pattern()` is declared to return a signed
>      int, but it either returns 0 or the index of the last dir separator
>      in a path.

That is not correct, the function contains the lines

               if (!kvi || !kvi->path)
                         return error(_("relative config include "
                                        "conditionals must come from 
files"));

so a negative return value is possible.

Thanks

Phillip

>      That index will always be positive, so the return type of
>      the function is changed to `size_t`, which allows us to drop a check
>      for `prefix < 0` at the only callsite. Furthermore, this fixes a
>      sign comparison warning when comparing `text.len < prefix`,
> 
>    - We treat `struct config_store_data::seen` as signed integer in
>      several places even though it's unsigned.
> 
>    - There are multiple trivial sign comparison warnings where we use a
>      signed loop index to iterate through an unsigned number of items.
> 
> Fix all of these issues and drop the `DISABLE_SIGN_COMPARE_WARNINGS`
> macro.
> 
> Signed-off-by: Patrick Steinhardt <ps@pks.im>
> ---
>   config.c | 33 +++++++++++++++------------------
>   1 file changed, 15 insertions(+), 18 deletions(-)
> 
> diff --git a/config.c b/config.c
> index 947fba3d8d4..a530c48a048 100644
> --- a/config.c
> +++ b/config.c
> @@ -6,8 +6,6 @@
>    *
>    */
>   
> -#define DISABLE_SIGN_COMPARE_WARNINGS
> -
>   #include "git-compat-util.h"
>   #include "abspath.h"
>   #include "date.h"
> @@ -197,12 +195,12 @@ static void add_trailing_starstar_for_dir(struct strbuf *pat)
>   		strbuf_addstr(pat, "**");
>   }
>   
> -static int prepare_include_condition_pattern(const struct key_value_info *kvi,
> -					     struct strbuf *pat)
> +static size_t prepare_include_condition_pattern(const struct key_value_info *kvi,
> +						struct strbuf *pat)
>   {
>   	struct strbuf path = STRBUF_INIT;
>   	char *expanded;
> -	int prefix = 0;
> +	size_t prefix = 0;
>   
>   	expanded = interpolate_path(pat->buf, 1);
>   	if (expanded) {
> @@ -239,7 +237,8 @@ static int include_by_gitdir(const struct key_value_info *kvi,
>   {
>   	struct strbuf text = STRBUF_INIT;
>   	struct strbuf pattern = STRBUF_INIT;
> -	int ret = 0, prefix;
> +	size_t prefix;
> +	int ret = 0;
>   	const char *git_dir;
>   	int already_tried_absolute = 0;
>   
> @@ -253,9 +252,6 @@ static int include_by_gitdir(const struct key_value_info *kvi,
>   	prefix = prepare_include_condition_pattern(kvi, &pattern);
>   
>   again:
> -	if (prefix < 0)
> -		goto done;
> -
>   	if (prefix > 0) {
>   		/*
>   		 * perform literal matching on the prefix part so that
> @@ -724,7 +720,6 @@ int git_config_from_parameters(config_fn_t fn, void *data)
>   	if (env) {
>   		unsigned long count;
>   		char *endp;
> -		int i;
>   
>   		count = strtoul(env, &endp, 10);
>   		if (*endp) {
> @@ -736,10 +731,10 @@ int git_config_from_parameters(config_fn_t fn, void *data)
>   			goto out;
>   		}
>   
> -		for (i = 0; i < count; i++) {
> +		for (unsigned long i = 0; i < count; i++) {
>   			const char *key, *value;
>   
> -			strbuf_addf(&envvar, "GIT_CONFIG_KEY_%d", i);
> +			strbuf_addf(&envvar, "GIT_CONFIG_KEY_%lu", i);
>   			key = getenv_safe(&to_free, envvar.buf);
>   			if (!key) {
>   				ret = error(_("missing config key %s"), envvar.buf);
> @@ -747,7 +742,7 @@ int git_config_from_parameters(config_fn_t fn, void *data)
>   			}
>   			strbuf_reset(&envvar);
>   
> -			strbuf_addf(&envvar, "GIT_CONFIG_VALUE_%d", i);
> +			strbuf_addf(&envvar, "GIT_CONFIG_VALUE_%lu", i);
>   			value = getenv_safe(&to_free, envvar.buf);
>   			if (!value) {
>   				ret = error(_("missing config value %s"), envvar.buf);
> @@ -1614,13 +1609,13 @@ int config_with_options(config_fn_t fn, void *data,
>   
>   static void configset_iter(struct config_set *set, config_fn_t fn, void *data)
>   {
> -	int i, value_index;
> +	int value_index;
>   	struct string_list *values;
>   	struct config_set_element *entry;
>   	struct configset_list *list = &set->list;
>   	struct config_context ctx = CONFIG_CONTEXT_INIT;
>   
> -	for (i = 0; i < list->nr; i++) {
> +	for (size_t i = 0; i < list->nr; i++) {
>   		entry = list->items[i].e;
>   		value_index = list->items[i].value_index;
>   		values = &entry->value_list;
> @@ -2470,10 +2465,11 @@ static ssize_t write_pair(int fd, const char *key, const char *value,
>    */
>   static void maybe_remove_section(struct config_store_data *store,
>   				 size_t *begin_offset, size_t *end_offset,
> -				 int *seen_ptr)
> +				 unsigned *seen_ptr)
>   {
>   	size_t begin;
> -	int i, seen, section_seen = 0;
> +	int section_seen = 0;
> +	unsigned int i, seen;
>   
>   	/*
>   	 * First, ensure that this is the first key, and that there are no
> @@ -2716,7 +2712,8 @@ int repo_config_set_multivar_in_file_gently(struct repository *r,
>   	} else {
>   		struct stat st;
>   		size_t copy_begin, copy_end;
> -		int i, new_line = 0;
> +		unsigned i;
> +		int new_line = 0;
>   		struct config_options opts;
>   
>   		if (!value_pattern)
>