On Tue, Sep 27 2022, Derrick Stolee via GitGitGadget wrote:
> From: Derrick Stolee <derrickstolee@xxxxxxxxxx>
>
> For the multi-valued config API methods, Git previously returned a NULL
> list instead of an empty list. Previous changes adjusted all callers to
> instead expect an empty, non-NULL list, making this a safe change.
>
> The next change will remove the NULL checks from all callers.
>
> Signed-off-by: Derrick Stolee <derrickstolee@xxxxxxxxxx>
> ---
> config.c | 3 ++-
> config.h | 6 +++---
> 2 files changed, 5 insertions(+), 4 deletions(-)
>
> diff --git a/config.c b/config.c
> index 0c41606c7d4..2d4ca1ae6dc 100644
> --- a/config.c
> +++ b/config.c
> @@ -2415,8 +2415,9 @@ int git_configset_get_value(struct config_set *cs, const char *key, const char *
>
> const struct string_list *git_configset_get_value_multi(struct config_set *cs, const char *key)
> {
> + static struct string_list empty_list = STRING_LIST_INIT_NODUP;
> struct config_set_element *e = configset_find_element(cs, key);
> - return e ? &e->value_list : NULL;
> + return e ? &e->value_list : &empty_list;
> }
>
> int git_configset_get_string(struct config_set *cs, const char *key, char **dest)
> diff --git a/config.h b/config.h
> index ca994d77147..9897b97c0b9 100644
> --- a/config.h
> +++ b/config.h
> @@ -458,7 +458,7 @@ int git_configset_add_parameters(struct config_set *cs);
> /**
> * Finds and returns the value list, sorted in order of increasing priority
> * for the configuration variable `key` and config set `cs`. When the
> - * configuration variable `key` is not found, returns NULL. The caller
> + * configuration variable `key` is not found, returns an empty list. The caller
> * should not free or modify the returned pointer, as it is owned by the cache.
> */
> const struct string_list *git_configset_get_value_multi(struct config_set *cs, const char *key);
> @@ -543,8 +543,8 @@ int git_config_get_value(const char *key, const char **value);
> /**
> * Finds and returns the value list, sorted in order of increasing priority
> * for the configuration variable `key`. When the configuration variable
> - * `key` is not found, returns NULL. The caller should not free or modify
> - * the returned pointer, as it is owned by the cache.
> + * `key` is not found, returns an empty list. The caller should not free or
> + * modify the returned pointer, as it is owned by the cache.
> */
> const struct string_list *git_config_get_value_multi(const char *key);
Aside from the "DWIM API" aspect of this (which I don't mind) I think
this is really taking the low-level function in the wrong direction, and
that we should just add a new simple wrapper instead.
I.e. both the pre-image API docs & this series gloss over the fact that
we'd not just return NULL here if the config wasn't there, but also if
git_config_parse_key() failed.
So it seems to me that a better direction would be starting with
something like the WIP below (which doesn't compile the whole code, I
stopped at config.[ch] and pack-bitmap.c). I.e. the same "int" return
and "dest" pattern that most other things in the config API have.
The functionality you want in this series would then just be a wrapper
for that which wouldn't care about the difference between "bad key" and
"no such config entry".
But I really think the low-level config API should care about the
difference, granted before your change it's rather crappy, and would
return NULL for both, but I think we can do better...
diff --git a/config.c b/config.c
index cbb5a3bab74..a9536d3a9e8 100644
--- a/config.c
+++ b/config.c
@@ -2275,23 +2275,28 @@ void read_very_early_config(config_fn_t cb, void *data)
config_with_options(cb, data, NULL, &opts);
}
-static struct config_set_element *configset_find_element(struct config_set *cs, const char *key)
+static int configset_find_element(struct config_set *cs, const char *key,
+ struct config_set_element **dest)
{
struct config_set_element k;
struct config_set_element *found_entry;
char *normalized_key;
+ int ret;
+
/*
* `key` may come from the user, so normalize it before using it
* for querying entries from the hashmap.
*/
- if (git_config_parse_key(key, &normalized_key, NULL))
- return NULL;
+ ret = git_config_parse_key(key, &normalized_key, NULL);
+ if (ret < 0)
+ return ret;
hashmap_entry_init(&k.ent, strhash(normalized_key));
k.key = normalized_key;
found_entry = hashmap_get_entry(&cs->config_hash, &k, ent, NULL);
free(normalized_key);
- return found_entry;
+ *dest = found_entry;
+ return 0;
}
static int configset_add_value(struct config_set *cs, const char *key, const char *value)
@@ -2300,8 +2305,11 @@ static int configset_add_value(struct config_set *cs, const char *key, const cha
struct string_list_item *si;
struct configset_list_item *l_item;
struct key_value_info *kv_info = xmalloc(sizeof(*kv_info));
+ int ret;
- e = configset_find_element(cs, key);
+ ret = configset_find_element(cs, key, &e);
+ if (ret < 0)
+ return ret;
/*
* Since the keys are being fed by git_config*() callback mechanism, they
* are already normalized. So simply add them without any further munging.
@@ -2400,24 +2408,34 @@ int git_configset_add_parameters(struct config_set *cs)
int git_configset_get_value(struct config_set *cs, const char *key, const char **value)
{
const struct string_list *values = NULL;
+ int ret;
+
/*
* Follows "last one wins" semantic, i.e., if there are multiple matches for the
* queried key in the files of the configset, the value returned will be the last
* value in the value list for that key.
*/
- values = git_configset_get_value_multi(cs, key);
+ ret = git_configset_get_value_multi(cs, key, &values);
+
+ if (ret < 0)
+ return ret;
- if (!values)
- return 1;
assert(values->nr > 0);
*value = values->items[values->nr - 1].string;
return 0;
}
-const struct string_list *git_configset_get_value_multi(struct config_set *cs, const char *key)
+int git_configset_get_value_multi(struct config_set *cs, const char *key,
+ const struct string_list **dest)
{
- struct config_set_element *e = configset_find_element(cs, key);
- return e ? &e->value_list : NULL;
+ struct config_set_element *e = NULL;
+ int ret;
+
+ ret = configset_find_element(cs, key, &e);
+ if (ret < 0)
+ return ret;
+ *dest = &e->value_list;
+ return 0;
}
int git_configset_get_string(struct config_set *cs, const char *key, char **dest)
@@ -2563,11 +2581,12 @@ int repo_config_get_value(struct repository *repo,
return git_configset_get_value(repo->config, key, value);
}
-const struct string_list *repo_config_get_value_multi(struct repository *repo,
- const char *key)
+int repo_config_get_value_multi(struct repository *repo,
+ const char *key,
+ const struct string_list **dest)
{
git_config_check_init(repo);
- return git_configset_get_value_multi(repo->config, key);
+ return git_configset_get_value_multi(repo->config, key, dest);
}
int repo_config_get_string(struct repository *repo,
@@ -2684,9 +2703,9 @@ int git_config_get_value(const char *key, const char **value)
return repo_config_get_value(the_repository, key, value);
}
-const struct string_list *git_config_get_value_multi(const char *key)
+int git_config_get_value_multi(const char *key, const struct string_list **dest)
{
- return repo_config_get_value_multi(the_repository, key);
+ return repo_config_get_value_multi(the_repository, key, dest);
}
int git_config_get_string(const char *key, char **dest)
@@ -2826,6 +2845,7 @@ void git_die_config(const char *key, const char *err, ...)
const struct string_list *values;
struct key_value_info *kv_info;
report_fn error_fn = get_error_routine();
+ int ret;
if (err) {
va_list params;
@@ -2833,7 +2853,9 @@ void git_die_config(const char *key, const char *err, ...)
error_fn(err, params);
va_end(params);
}
- values = git_config_get_value_multi(key);
+ ret = git_config_get_value_multi(key, &values);
+ if (ret < 0)
+ BUG("...");
kv_info = values->items[values->nr - 1].util;
git_die_config_linenr(key, kv_info->filename, kv_info->linenr);
}
diff --git a/config.h b/config.h
index ca994d77147..99b8dc1944c 100644
--- a/config.h
+++ b/config.h
@@ -461,7 +461,8 @@ int git_configset_add_parameters(struct config_set *cs);
* configuration variable `key` is not found, returns NULL. The caller
* should not free or modify the returned pointer, as it is owned by the cache.
*/
-const struct string_list *git_configset_get_value_multi(struct config_set *cs, const char *key);
+int git_configset_get_value_multi(struct config_set *cs, const char *key,
+ const struct string_list **dest);
/**
* Clears `config_set` structure, removes all saved variable-value pairs.
@@ -495,8 +496,9 @@ struct repository;
void repo_config(struct repository *repo, config_fn_t fn, void *data);
int repo_config_get_value(struct repository *repo,
const char *key, const char **value);
-const struct string_list *repo_config_get_value_multi(struct repository *repo,
- const char *key);
+int repo_config_get_value_multi(struct repository *repo,
+ const char *key,
+ const struct string_list **dest);
int repo_config_get_string(struct repository *repo,
const char *key, char **dest);
int repo_config_get_string_tmp(struct repository *repo,
@@ -546,7 +548,8 @@ int git_config_get_value(const char *key, const char **value);
* `key` is not found, returns NULL. The caller should not free or modify
* the returned pointer, as it is owned by the cache.
*/
-const struct string_list *git_config_get_value_multi(const char *key);
+int git_config_get_value_multi(const char *key,
+ const struct string_list **dest);
/**
* Resets and invalidates the config cache.
diff --git a/pack-bitmap.c b/pack-bitmap.c
index 440407f1be7..0d704dc76ef 100644
--- a/pack-bitmap.c
+++ b/pack-bitmap.c
@@ -2301,7 +2301,13 @@ int bitmap_is_midx(struct bitmap_index *bitmap_git)
const struct string_list *bitmap_preferred_tips(struct repository *r)
{
- return repo_config_get_value_multi(r, "pack.preferbitmaptips");
+ const struct string_list *dest;
+ int ret;
+
+ ret = repo_config_get_value_multi(r, "pack.preferbitmaptips", &dest);
+ if (ret < 0)
+ BUG("got %d from repo_config_get_value_multi()", ret);
+ return dest;
}
int bitmap_is_preferred_refname(struct repository *r, const char *refname)
