[pacman-dev] [PATCH] Handle provides with -Q

[Andrew Gregory]

On 04/01/16 at 02:23pm, Allan McRae wrote:
> It is useful to be able to use "pacman -Qi" on any dependency, even if that
> dependency is a provide.  For example, on Arch Linux systems, "sh" is provided
> by the "bash" package, and many packages depend on "sh". Querying the what
> package the "sh" dependency, currently first requires searching for "sh".

s/Querying the what package/Querying the package that provides/?

> This patch allows the use of "pacman -Qi" on a provide.
> 
> Fixes FS#20650.
> 
> Signed-off-by: Allan McRae <allan at archlinux.org>
> ---
>  src/pacman/query.c | 30 ++++++++++++++++++++++++++++++
>  1 file changed, 30 insertions(+)
> 
> diff --git a/src/pacman/query.c b/src/pacman/query.c
> index 0cc12e6..19e4b3f 100644
> --- a/src/pacman/query.c
> +++ b/src/pacman/query.c
> @@ -80,6 +80,32 @@ static int search_path(char **filename, struct stat *bufptr)
>  	return -1;
>  }
>  
> +static alpm_pkg_t *find_provider(alpm_db_t *db_local, const char *name)
> +{
> +	alpm_list_t *packages, *i;
> +	alpm_pkg_t *pkg = NULL;
> +	int found = 0;
> +
> +	packages = alpm_db_get_pkgcache(db_local);
> +
> +	for(i = packages; i && !found; i = alpm_list_next(i)) {
> +		alpm_list_t *provides, *p;
> +
> +		pkg = i->data;
> +		provides = alpm_pkg_get_provides(pkg);
> +
> +		for(p = provides; p; p = alpm_list_next(p)) {
> +			alpm_depend_t *d = p->data;
> +			if(strcmp(name, d->name) == 0) {
> +				found = 1;
> +				break;
> +			}
> +		}
> +	}
> +
> +	return pkg;
> +}

The package can be returned immediately, so there's no need for the
found/break.  More importantly, because pkg is used to refer to the
package currently being checked, if no provider is found it will just
return the last package in the list:

 pacman -Qi not-a-real-package-name # prints zziplib

> +
>  static void print_query_fileowner(const char *filename, alpm_pkg_t *info)
>  {
>  	if(!config->quiet) {
> @@ -462,6 +488,10 @@ int pacman_query(alpm_list_t *targets)
>  			alpm_pkg_load(config->handle, strname, 1, 0, &pkg);
>  		} else {
>  			pkg = alpm_db_get_pkg(db_local, strname);
> +			/* if pkg is not found, return the first package that provides it */
> +			if(pkg == NULL) {
> +				pkg = find_provider(db_local, strname);

Any reason not to just use alpm_find_satisfier here?

> +			}
>  		}
>  
>  		if(pkg == NULL) {
> -- 
> 2.7.4