Add a function to set a non-default work tree

This function may only be used before the work tree is used.

Signed-off-by: Daniel Barkalow <barkalow@iabervon.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

cache.h

@@ -311,6 +311,7 @@ extern char *get_index_file(void);
 extern char *get_graft_file(void);
 extern int set_git_dir(const char *path);
 extern const char *get_git_work_tree(void);
+extern void set_git_work_tree(const char *tree);
 
 #define ALTERNATE_DB_ENVIRONMENT "GIT_ALTERNATE_OBJECT_DIRECTORIES"
 

environment.c

@@ -41,7 +41,7 @@ enum branch_track git_branch_track = BRANCH_TRACK_REMOTE;
 
 /* This is set by setup_git_dir_gently() and/or git_default_config() */
 char *git_work_tree_cfg;
-static const char *work_tree;
+static char *work_tree;
 
 static const char *git_dir;
 static char *git_object_dir, *git_index_file, *git_refs_dir, *git_graft_file;
@@ -81,10 +81,26 @@ const char *get_git_dir(void)
 	return git_dir;
 }
 
+static int git_work_tree_initialized;
+
+/*
+ * Note.  This works only before you used a work tree.  This was added
+ * primarily to support git-clone to work in a new repository it just
+ * created, and is not meant to flip between different work trees.
+ */
+void set_git_work_tree(const char *new_work_tree)
+{
+	if (is_bare_repository_cfg >= 0)
+		die("cannot set work tree after initialization");
+	git_work_tree_initialized = 1;
+	free(work_tree);
+	work_tree = xstrdup(make_absolute_path(new_work_tree));
+	is_bare_repository_cfg = 0;
+}
+
 const char *get_git_work_tree(void)
 {
-	static int initialized = 0;
-	if (!initialized) {
+	if (!git_work_tree_initialized) {
 		work_tree = getenv(GIT_WORK_TREE_ENVIRONMENT);
 		/* core.bare = true overrides implicit and config work tree */
 		if (!work_tree && is_bare_repository_cfg < 1) {
@@ -94,7 +110,7 @@ const char *get_git_work_tree(void)
 				work_tree = xstrdup(make_absolute_path(git_path(work_tree)));
 		} else if (work_tree)
 			work_tree = xstrdup(make_absolute_path(work_tree));
-		initialized = 1;
+		git_work_tree_initialized = 1;
 		if (work_tree)
 			is_bare_repository_cfg = 0;
 	}