config: really delete variables

Instead of just setting the value to NULL, which gives unwanted
results when asking for that variable after deleting it, delete the
variable from the list and re-write the file.

3 files changed, 38 insertions, 1 deletions

diff --git a/include/git2/config.h b/include/git2/config.h
index 36647591a..f78fe40a0 100644
--- a/include/git2/config.h
+++ b/include/git2/config.h
@@ -30,6 +30,7 @@ struct git_config_file {
 	int (*open)(struct git_config_file *);
 	int (*get)(struct git_config_file *, const char *key, const char **value);
 	int (*set)(struct git_config_file *, const char *key, const char *value);
+	int (*delete)(struct git_config_file *, const char *key);
 	int (*foreach)(struct git_config_file *, int (*fn)(const char *, const char *, void *), void *data);
 	void (*free)(struct git_config_file *);
 };
diff --git a/src/config.c b/src/config.c
index 2e341d256..ed7c947ed 100644
--- a/src/config.c
+++ b/src/config.c
@@ -162,7 +162,16 @@ int git_config_foreach(git_config *cfg, int (*fn)(const char *, const char *, vo
 
 int git_config_delete(git_config *cfg, const char *name)
 {
-	return git_config_set_string(cfg, name, NULL);
+	file_internal *internal;
+	git_config_file *file;
+
+	if (cfg->files.length == 0)
+		return git__throw(GIT_EINVALIDARGS, "Cannot delete variable; no files open in the `git_config` instance");
+
+	internal = git_vector_get(&cfg->files, 0);
+	file = internal->file;
+
+	return file->delete(file, name);
 }
 
 /**************
diff --git a/src/config_file.c b/src/config_file.c
index 7a5865210..207bd2bdd 100644
--- a/src/config_file.c
+++ b/src/config_file.c
@@ -404,6 +404,32 @@ static int config_get(git_config_file *cfg, const char *name, const char **out)
 	return error == GIT_SUCCESS ? GIT_SUCCESS : git__rethrow(error, "Failed to get config value for %s", name);
 }
 
+static int config_delete(git_config_file *cfg, const char *name)
+{
+	cvar_t *iter, *prev;
+	diskfile_backend *b = (diskfile_backend *)cfg;
+
+	CVAR_LIST_FOREACH (&b->var_list, iter) {
+		/* This is a bit hacky because we use a singly-linked list */
+		if (cvar_match_name(iter, name)) {
+			if (CVAR_LIST_HEAD(&b->var_list) == iter)
+				CVAR_LIST_HEAD(&b->var_list) = CVAR_LIST_NEXT(iter);
+			else
+				CVAR_LIST_REMOVE_AFTER(prev);
+
+			git__free(iter->value);
+			iter->value = NULL;
+			config_write(b, iter);
+			cvar_free(iter);
+			return GIT_SUCCESS;
+		}
+		/* Store it for the next round */
+		prev = iter;
+	}
+
+	return git__throw(GIT_ENOTFOUND, "Variable '%s' not found", name);
+}
+
 int git_config_file__ondisk(git_config_file **out, const char *path)
 {
 	diskfile_backend *backend;
@@ -423,6 +449,7 @@ int git_config_file__ondisk(git_config_file **out, const char *path)
 	backend->parent.open = config_open;
 	backend->parent.get = config_get;
 	backend->parent.set = config_set;
+	backend->parent.delete = config_delete;
 	backend->parent.foreach = file_foreach;
 	backend->parent.free = backend_free;