Fix saving remotes with several fetch/push ref specs.

At some moment git_config_delete_entry lost the ability to delete one entry of
a multivar configuration. The moment you had more than one fetch or push
ref spec for a remote you will not be able to save that remote anymore. The
changes in network::remote::remotes::save show that problem.

I needed to create a new git_config_delete_multivar because I was not able to
remove one or several entries of a multivar config with the current API.
Several tries modifying how git_config_set_multivar(..., NULL) behaved were
not successful.

git_config_delete_multivar is very similar to git_config_set_multivar, and
delegates into config_delete_multivar of config_file. This function search
for the cvar_t that will be deleted, storing them in a temporal array, and
rebuilding the linked list. After calling config_write to delete the entries,
the cvar_t stored in the temporal array are freed.

There is a little fix in config_write, it avoids an infinite loop when using
a regular expression (case for the multivars). This error was found by the
test network::remote::remotes::tagopt.

2 files changed, 12 insertions, 0 deletions

diff --git a/include/git2/config.h b/include/git2/config.h
index f14415148..95da4bc03 100644
--- a/include/git2/config.h
+++ b/include/git2/config.h
@@ -435,6 +435,17 @@ GIT_EXTERN(int) git_config_set_multivar(git_config *cfg, const char *name, const
 GIT_EXTERN(int) git_config_delete_entry(git_config *cfg, const char *name);
 
 /**
+ * Deletes one or several entries from a multivar in the local config file.
+ *
+ * @param cfg where to look for the variables
+ * @param name the variable's name
+ * @param regexp a regular expression to indicate which values to delete
+ *
+ * @return 0 or an error code
+ */
+GIT_EXTERN(int) git_config_delete_multivar(git_config *cfg, const char *name, const char *regexp);
+
+/**
  * Perform an operation on each config variable.
  *
  * The callback receives the normalized name and value of each variable
diff --git a/include/git2/sys/config.h b/include/git2/sys/config.h
index 7572ace51..419ad7ea7 100644
--- a/include/git2/sys/config.h
+++ b/include/git2/sys/config.h
@@ -61,6 +61,7 @@ struct git_config_backend {
 	int (*set)(struct git_config_backend *, const char *key, const char *value);
 	int (*set_multivar)(git_config_backend *cfg, const char *name, const char *regexp, const char *value);
 	int (*del)(struct git_config_backend *, const char *key);
+	int (*del_multivar)(struct git_config_backend *, const char *key, const char *regexp);
 	int (*iterator)(git_config_iterator **, struct git_config_backend *);
 	int (*refresh)(struct git_config_backend *);
 	void (*free)(struct git_config_backend *);