Re: [PATCH 0/7] Rewrite `git_config()` using config-set API

[Tanay Abhra <tanayabh@gmail.com>]

> 
> Are you done with the original series, or do you still want to fix
> the const-ness issue with the string pointer before working on
> follow-up topics like this one?
>

I am attaching the v12 with two new functions git_configset_get_string() &
git_configset_get_string_const().

Diff between v11 and v12 is appended below for easy review.

-- 8< --
diff --git a/Documentation/technical/api-config.txt b/Documentation/technical/api-config.txt
index 8a86e45..815c1ee 100644
--- a/Documentation/technical/api-config.txt
+++ b/Documentation/technical/api-config.txt
@@ -138,13 +138,18 @@ as well as retrieval for the queried variable, including:
 	Similar to `git_config_get_bool`, except that it returns -1 on error
 	rather than dying.

-`int git_config_get_string(const char *key, const char **dest)`::
+`int git_config_get_string_const(const char *key, const char **dest)`::

 	Allocates and copies the retrieved string into the `dest` parameter for
 	the configuration variable `key`; if NULL string is given, prints an
 	error message and returns -1. When the configuration variable `key` is
 	not found, returns 1 without touching `dest`.

+`int git_config_get_string(const char *key, char **dest)`::
+
+	Similar to `git_config_get_string_const`, except that retrieved value
+	copied into the `dest` parameter is a mutable string.
+
 `int git_config_get_pathname(const char *key, const char **dest)`::

 	Similar to `git_config_get_string`, but expands `~` or `~user` into
diff --git a/cache.h b/cache.h
index 2f63fd1..7292aef 100644
--- a/cache.h
+++ b/cache.h
@@ -1361,7 +1361,8 @@ extern int git_configset_add_file(struct config_set *cs, const char *filename);
 extern int git_configset_get_value(struct config_set *cs, const char *key, const char **value);
 extern const struct string_list *git_configset_get_value_multi(struct config_set *cs, const char *key);
 extern void git_configset_clear(struct config_set *cs);
-extern int git_configset_get_string(struct config_set *cs, const char *key, const char **dest);
+extern int git_configset_get_string_const(struct config_set *cs, const char *key, const char **dest);
+extern int git_configset_get_string(struct config_set *cs, const char *key, char **dest);
 extern int git_configset_get_int(struct config_set *cs, const char *key, int *dest);
 extern int git_configset_get_ulong(struct config_set *cs, const char *key, unsigned long *dest);
 extern int git_configset_get_bool(struct config_set *cs, const char *key, int *dest);
@@ -1373,7 +1374,8 @@ extern int git_config_get_value(const char *key, const char **value);
 extern const struct string_list *git_config_get_value_multi(const char *key);
 extern void git_config_clear(void);
 extern void git_config_iter(config_fn_t fn, void *data);
-extern int git_config_get_string(const char *key, const char **dest);
+extern int git_config_get_string_const(const char *key, const char **dest);
+extern int git_config_get_string(const char *key, char **dest);
 extern int git_config_get_int(const char *key, int *dest);
 extern int git_config_get_ulong(const char *key, unsigned long *dest);
 extern int git_config_get_bool(const char *key, int *dest);
diff --git a/config.c b/config.c
index 22971e9..0d799e0 100644
--- a/config.c
+++ b/config.c
@@ -1332,7 +1332,7 @@ const struct string_list *git_configset_get_value_multi(struct config_set *cs, c
 	return e ? &e->value_list : NULL;
 }

-int git_configset_get_string(struct config_set *cs, const char *key, const char **dest)
+int git_configset_get_string_const(struct config_set *cs, const char *key, const char **dest)
 {
 	const char *value;
 	if (!git_configset_get_value(cs, key, &value))
@@ -1341,6 +1341,19 @@ int git_configset_get_string(struct config_set *cs, const char *key, const char
 		return 1;
 }

+int git_configset_get_string(struct config_set *cs, const char *key, char **dest)
+{
+	const char *value;
+	if (!git_configset_get_value(cs, key, &value)) {
+		if (!value)
+			return config_error_nonbool(key);
+		*dest = xstrdup(value);
+		return 0;
+	}
+	else
+		return 1;
+}
+
 int git_configset_get_int(struct config_set *cs, const char *key, int *dest)
 {
 	const char *value;
@@ -1430,7 +1443,13 @@ const struct string_list *git_config_get_value_multi(const char *key)
 	return git_configset_get_value_multi(&the_config_set, key);
 }

-int git_config_get_string(const char *key, const char **dest)
+int git_config_get_string_const(const char *key, const char **dest)
+{
+	git_config_check_init();
+	return git_configset_get_string_const(&the_config_set, key, dest);
+}
+
+int git_config_get_string(const char *key, char **dest)
 {
 	git_config_check_init();
 	return git_configset_get_string(&the_config_set, key, dest);
-- 8< --