[PATCH 06/10] Completely move out worktree setup from setup_git_directory_gently()

["Nguyễn Thái Ngọc Duy" <pclouds@gmail.com>]

This was impossible earlier because git_dir can be relative. Now that
git_dir is absolute, I see no reason for worktree setup inside
setup_git_directory_gently(). The semantic is now clearer: if you need
worktree, call setup_work_tree yourself (well, I will clean up
setup_git_directory() part later)

This patch will free some commands from prefix handling if they don't
ever need worktree.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 builtin-apply.c          |    7 +++++--
 builtin-bundle.c         |    9 ++-------
 builtin-config.c         |   15 +++++----------
 builtin-diff-files.c     |   11 ++++++-----
 builtin-diff.c           |   11 ++++++-----
 builtin-upload-archive.c |    4 ++--
 cache.h                  |    2 +-
 git.c                    |    6 +-----
 hash-object.c            |    8 +-------
 setup.c                  |   34 +++++++++++++++++-----------------
 10 files changed, 46 insertions(+), 61 deletions(-)

diff --git a/builtin-apply.c b/builtin-apply.c
index a3f075d..b77e84e 100644
--- a/builtin-apply.c
+++ b/builtin-apply.c
@@ -2998,8 +2998,11 @@ int cmd_apply(int argc, const char **argv, const char *unused_prefix)
 
 	const char *whitespace_option = NULL;
 
-	prefix = setup_git_directory_gently(&is_not_gitdir);
-	prefix_length = prefix ? strlen(prefix) : 0;
+	setup_git_directory_gently(&is_not_gitdir);
+	if (!is_not_gitdir && is_inside_work_tree()) {
+		prefix = setup_work_tree(NULL);
+		prefix_length = prefix ? strlen(prefix) : 0;
+	}
 	git_config(git_apply_config);
 	if (apply_default_whitespace)
 		parse_whitespace_option(apply_default_whitespace);
diff --git a/builtin-bundle.c b/builtin-bundle.c
index 9f38e21..2a7687e 100644
--- a/builtin-bundle.c
+++ b/builtin-bundle.c
@@ -11,7 +11,7 @@
 
 static const char *bundle_usage="git-bundle (create <bundle> <git-rev-list args> | verify <bundle> | list-heads <bundle> [refname]... | unbundle <bundle> [refname]... )";
 
-int cmd_bundle(int argc, const char **argv, const char *prefix)
+int cmd_bundle(int argc, const char **argv, const char *unused_prefix)
 {
 	struct bundle_header header;
 	int nongit = 0;
@@ -27,12 +27,7 @@ int cmd_bundle(int argc, const char **argv, const char *prefix)
 	argc -= 2;
 	argv += 2;
 
-	prefix = setup_git_directory_gently(&nongit);
-	if (prefix && bundle_file[0] != '/') {
-		snprintf(buffer, sizeof(buffer), "%s/%s", prefix, bundle_file);
-		bundle_file = buffer;
-	}
-
+	setup_git_directory_gently(&nongit);
 	memset(&header, 0, sizeof(header));
 	if (strcmp(cmd, "create") && (bundle_fd =
 				read_bundle_header(bundle_file, &header)) < 0)
diff --git a/builtin-config.c b/builtin-config.c
index 2b9a426..ae6be9b 100644
--- a/builtin-config.c
+++ b/builtin-config.c
@@ -262,11 +262,11 @@ static int get_colorbool(int argc, const char **argv)
 	}
 }
 
-int cmd_config(int argc, const char **argv, const char *prefix)
+int cmd_config(int argc, const char **argv, const char *unused_prefix)
 {
 	int nongit = 0;
 	char* value;
-	const char *file = setup_git_directory_gently(&nongit);
+	setup_git_directory_gently(&nongit);
 
 	while (1 < argc) {
 		if (!strcmp(argv[1], "--int"))
@@ -276,8 +276,8 @@ int cmd_config(int argc, const char **argv, const char *prefix)
 		else if (!strcmp(argv[1], "--list") || !strcmp(argv[1], "-l")) {
 			if (argc != 2)
 				usage(git_config_set_usage);
-			if (git_config(show_all_config) < 0 && file && errno)
-				die("unable to read config file %s: %s", file,
+			if (git_config(show_all_config) < 0 && errno)
+				die("unable to read config file: %s",
 				    strerror(errno));
 			return 0;
 		}
@@ -296,12 +296,7 @@ int cmd_config(int argc, const char **argv, const char *prefix)
 		else if (!strcmp(argv[1], "--file") || !strcmp(argv[1], "-f")) {
 			if (argc < 3)
 				usage(git_config_set_usage);
-			if (!is_absolute_path(argv[2]) && file)
-				file = prefix_filename(file, strlen(file),
-						       argv[2]);
-			else
-				file = argv[2];
-			setenv(CONFIG_ENVIRONMENT, file, 1);
+			setenv(CONFIG_ENVIRONMENT, argv[2], 1);
 			argc--;
 			argv++;
 		}
diff --git a/builtin-diff-files.c b/builtin-diff-files.c
index 11671a8..826f052 100644
--- a/builtin-diff-files.c
+++ b/builtin-diff-files.c
@@ -13,21 +13,22 @@ static const char diff_files_usage[] =
 "git-diff-files [-q] [-0/-1/2/3 |-c|--cc|--no-index] [<common diff options>] [<path>...]"
 COMMON_DIFF_OPTIONS_HELP;
 
-int cmd_diff_files(int argc, const char **argv, const char *prefix)
+int cmd_diff_files(int argc, const char **argv, const char *unused_prefix)
 {
 	struct rev_info rev;
 	int nongit = 0;
 	int result;
 
-	prefix = setup_git_directory_gently(&nongit);
-	init_revisions(&rev, prefix);
+	setup_git_directory_gently(&nongit);
+	init_revisions(&rev, NULL);
 	git_config(git_diff_basic_config); /* no "diff" UI options */
 	rev.abbrev = 0;
 
-	if (!setup_diff_no_index(&rev, argc, argv, nongit, prefix))
+	if (!setup_diff_no_index(&rev, argc, argv, nongit, NULL))
 		argc = 0;
 	else {
-		rev.prefix = setup_work_tree(prefix);
+		init_revisions(&rev, setup_work_tree(NULL));
+		rev.abbrev = 0;
 		argc = setup_revisions(argc, argv, &rev, NULL);
 	}
 	if (!rev.diffopt.output_format)
diff --git a/builtin-diff.c b/builtin-diff.c
index 254e5a0..a92ab0e 100644
--- a/builtin-diff.c
+++ b/builtin-diff.c
@@ -202,7 +202,7 @@ static void refresh_index_quietly(void)
 	rollback_lock_file(lock_file);
 }
 
-int cmd_diff(int argc, const char **argv, const char *prefix)
+int cmd_diff(int argc, const char **argv, const char *unused_prefix)
 {
 	int i;
 	struct rev_info rev;
@@ -233,19 +233,20 @@ int cmd_diff(int argc, const char **argv, const char *prefix)
 	 * Other cases are errors.
 	 */
 
-	prefix = setup_git_directory_gently(&nongit);
+	setup_git_directory_gently(&nongit);
 	git_config(git_diff_ui_config);
 
 	if (diff_use_color_default == -1)
 		diff_use_color_default = git_use_color_default;
 
-	init_revisions(&rev, prefix);
+	init_revisions(&rev, NULL);
 	rev.diffopt.skip_stat_unmatch = !!diff_auto_refresh_index;
 
-	if (!setup_diff_no_index(&rev, argc, argv, nongit, prefix))
+	if (!setup_diff_no_index(&rev, argc, argv, nongit, NULL))
 		argc = 0;
 	else {
-		rev.prefix = setup_work_tree(prefix);
+		init_revisions(&rev, setup_work_tree(NULL));
+		rev.diffopt.skip_stat_unmatch = !!diff_auto_refresh_index;
 		argc = setup_revisions(argc, argv, &rev, NULL);
 	}
 	if (!rev.diffopt.output_format) {
diff --git a/builtin-upload-archive.c b/builtin-upload-archive.c
index 48ae09e..4f7fa35 100644
--- a/builtin-upload-archive.c
+++ b/builtin-upload-archive.c
@@ -17,7 +17,7 @@ static const char lostchild[] =
 "git-upload-archive: archiver process was lost";
 
 
-static int run_upload_archive(int argc, const char **argv, const char *prefix)
+static int run_upload_archive(int argc, const char **argv, const char *unused_prefix)
 {
 	struct archiver ar;
 	const char *sent_argv[MAX_ARGS];
@@ -67,7 +67,7 @@ static int run_upload_archive(int argc, const char **argv, const char *prefix)
 	/* parse all options sent by the client */
 	treeish_idx = parse_archive_args(sent_argc, sent_argv, &ar);
 
-	parse_treeish_arg(sent_argv + treeish_idx, &ar.args, prefix);
+	parse_treeish_arg(sent_argv + treeish_idx, &ar.args, NULL);
 	parse_pathspec_arg(sent_argv + treeish_idx + 1, &ar.args);
 
 	return ar.write_archive(&ar.args);
diff --git a/cache.h b/cache.h
index b98f7e8..33dcfb1 100644
--- a/cache.h
+++ b/cache.h
@@ -316,7 +316,7 @@ extern const char *get_git_work_tree(void);
 
 extern const char **get_pathspec(const char *prefix, const char **pathspec);
 extern const char *setup_work_tree(const char *prefix);
-extern const char *setup_git_directory_gently(int *);
+extern void setup_git_directory_gently(int *);
 extern const char *setup_git_directory(void);
 extern const char *prefix_path(const char *prefix, int len, const char *path);
 extern const char *prefix_filename(const char *prefix, int len, const char *path);
diff --git a/git.c b/git.c
index 9e53a2e..d87c33e 100644
--- a/git.c
+++ b/git.c
@@ -143,13 +143,12 @@ static int split_cmdline(char *cmdline, const char ***argv)
 static int handle_alias(int *argcp, const char ***argv)
 {
 	int nongit = 0, envchanged = 0, ret = 0, saved_errno = errno;
-	const char *subdir;
 	int count, option_count;
 	const char** new_argv;
 	const char *alias_command;
 	char *alias_string;
 
-	subdir = setup_git_directory_gently(&nongit);
+	setup_git_directory_gently(&nongit);
 
 	alias_command = (*argv)[0];
 	alias_string = alias_lookup(alias_command);
@@ -205,9 +204,6 @@ static int handle_alias(int *argcp, const char ***argv)
 		ret = 1;
 	}
 
-	if (subdir)
-		chdir(subdir);
-
 	errno = saved_errno;
 
 	return ret;
diff --git a/hash-object.c b/hash-object.c
index 46d57ad..5986701 100644
--- a/hash-object.c
+++ b/hash-object.c
@@ -38,14 +38,11 @@ int main(int argc, char **argv)
 	int i;
 	const char *type = blob_type;
 	int write_object = 0;
-	const char *prefix = NULL;
-	int prefix_length = -1;
 	int no_more_flags = 0;
 	int hashstdin = 0;
 	int nongit = 0;
 
-	prefix = setup_git_directory_gently(&nongit);
-	prefix_length = prefix ? strlen(prefix) : 0;
+	setup_git_directory_gently(&nongit);
 	git_config(git_default_config);
 
 	for (i = 1 ; i < argc; i++) {
@@ -80,9 +77,6 @@ int main(int argc, char **argv)
 				hash_stdin(type, write_object);
 				hashstdin = 0;
 			}
-			if (0 <= prefix_length)
-				arg = prefix_filename(prefix, prefix_length,
-						      arg);
 			hash_object(arg, type_from_string(type), write_object);
 			no_more_flags = 1;
 		}
diff --git a/setup.c b/setup.c
index 6c908a5..78ae2f9 100644
--- a/setup.c
+++ b/setup.c
@@ -301,7 +301,7 @@ static int check_repository_format_gently(int *nongit_ok)
  * We cannot decide in this function whether we are in the work tree or
  * not, since the config can only be read _after_ this function was called.
  */
-const char *setup_git_directory_gently(int *nongit_ok)
+void setup_git_directory_gently(int *nongit_ok)
 {
 	const char *work_tree_env = getenv(GIT_WORK_TREE_ENVIRONMENT);
 	static char cwd[PATH_MAX+1];
@@ -335,11 +335,11 @@ const char *setup_git_directory_gently(int *nongit_ok)
 				inside_work_tree = 1;
 			}
 			check_repository_format_gently(nongit_ok);
-			return NULL;
+			return;
 		}
 		if (nongit_ok) {
 			*nongit_ok = 1;
-			return NULL;
+			return;
 		}
 		die("Not a git repository: '%s'", gitdirenv);
 	}
@@ -364,9 +364,12 @@ const char *setup_git_directory_gently(int *nongit_ok)
 			inside_git_dir = 1;
 			if (!work_tree_env)
 				inside_work_tree = 0;
-			setenv(GIT_DIR_ENVIRONMENT, ".", 1);
+			if (chdir(cwd))
+				die("Cannot come back to cwd");
+			cwd[offset] = '\0';
+			setenv(GIT_DIR_ENVIRONMENT, cwd, 1);
 			check_repository_format_gently(nongit_ok);
-			return NULL;
+			return;
 		}
 		chdir("..");
 		do {
@@ -375,27 +378,23 @@ const char *setup_git_directory_gently(int *nongit_ok)
 					if (chdir(cwd))
 						die("Cannot come back to cwd");
 					*nongit_ok = 1;
-					return NULL;
+					return;
 				}
 				die("Not a git repository");
 			}
 		} while (cwd[--offset] != '/');
 	}
 
+	if (chdir(cwd))
+		die("Cannot come back to cwd");
 	inside_git_dir = 0;
 	if (!work_tree_env)
 		inside_work_tree = 1;
 	git_work_tree_cfg = xstrndup(cwd, offset);
-	if (check_repository_format_gently(nongit_ok))
-		return NULL;
-	if (offset == len)
-		return NULL;