Re: [PATCH v7 11/11] submodule: detect conflicts with existing gitdir configs

> diff --git a/submodule.c b/submodule.c
> index 834c794b7d..d778e8eca7 100644
> --- a/submodule.c
> +++ b/submodule.c
> @@ -2289,6 +2289,61 @@ static int check_casefolding_conflict(const char *git_dir,
>  	return ret;
>  }
>  
> +struct submodule_from_gitdir_cb {
> +	const char *gitdir;
> +	const char *submodule_name;
> +	bool conflict_found;
> +};
> +
> +static int find_conflict_by_gitdir_cb(const char *var, const char *value,
> +				      const struct config_context *ctx UNUSED, void *data)
> +{
> +	struct submodule_from_gitdir_cb *cb = data;
> +	const char *submodule_name_start;
> +	size_t submodule_name_len;
> +	const char *suffix = ".gitdir";
> +	size_t suffix_len = strlen(suffix);
> +
> +	if (!skip_prefix(var, "submodule.", &submodule_name_start))
> +		return 0;
> +
> +	/* Check if submodule_name_start ends with ".gitdir" */
> +	submodule_name_len = strlen(submodule_name_start);
> +	if (submodule_name_len < suffix_len ||
> +	    strcmp(submodule_name_start + submodule_name_len - suffix_len, suffix) != 0)
> +		return 0; /* Does not end with ".gitdir" */
> +
> +	submodule_name_len -= suffix_len;
> +
> +	/*
> +	 * A conflict happens if:
> +	 * 1. The submodule names are different and
> +	 * 2. The gitdir paths resolve to the same absolute path
> +	 */
> +	if (value && strncmp(cb->submodule_name, submodule_name_start, submodule_name_len)) {
> +		char *abs_path_cb = absolute_pathdup(cb->gitdir);
> +		char *abs_path_value = absolute_pathdup(value);
> +
> +		cb->conflict_found = !strcmp(abs_path_cb, abs_path_value);
> +
> +		free(abs_path_cb);
> +		free(abs_path_value);
> +	}
> +
> +	return cb->conflict_found;
> +}