git init: --bare/--shared overrides system/global config

If core.bare or core.sharedRepository are set in /etc/gitconfig or
~/.gitconfig, then 'git init' will read the values when constructing a
new config file; reading them, however, will override the values
specified on the command line.  In the case of --bare, this ends up
causing a segfault, without the repository being properly initialised;
in the case of --shared, the permissions are set according to the
existing config settings, not what was specified on the command line.

This fix saves any specified values for --bare and --shared prior to
reading existing config settings, and restores them after reading but
before writing the new config file.  core.bare is ignored in all
situations, while core.sharedRepository will only be used if --shared
is not specified to git init.

Also includes testcases which use a specified global config file
override, demonstrating the former failure scenario.

Signed-off-by: Deskin Miller <deskinm@umich.edu>
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

builtin-init-db.c

@@ -17,6 +17,9 @@
 #define TEST_FILEMODE 1
 #endif
 
+static int init_is_bare_repository = 0;
+static int init_shared_repository = -1;
+
 static void safe_create_dir(const char *dir, int share)
 {
 	if (mkdir(dir, 0777) < 0) {
@@ -191,6 +194,9 @@ static int create_default_files(const char *template_path)
 	copy_templates(template_path);
 
 	git_config(git_default_config, NULL);
+	is_bare_repository_cfg = init_is_bare_repository;
+	if (init_shared_repository != -1)
+		shared_repository = init_shared_repository;
 
 	/*
 	 * We would have created the above under user's umask -- under
@@ -277,6 +283,8 @@ int init_db(const char *template_dir, unsigned int flags)
 
 	safe_create_dir(get_git_dir(), 0);
 
+	init_is_bare_repository = is_bare_repository();
+
 	/* Check to see if the repository version is right.
 	 * Note that a newly created repository does not have
 	 * config file, so this will not fail.  What we are catching
@@ -381,9 +389,9 @@ int cmd_init_db(int argc, const char **argv, const char *prefix)
 			setenv(GIT_DIR_ENVIRONMENT, getcwd(git_dir,
 						sizeof(git_dir)), 0);
 		} else if (!strcmp(arg, "--shared"))
-			shared_repository = PERM_GROUP;
+			init_shared_repository = PERM_GROUP;
 		else if (!prefixcmp(arg, "--shared="))
-			shared_repository = git_config_perm("arg", arg+9);
+			init_shared_repository = git_config_perm("arg", arg+9);
 		else if (!strcmp(arg, "-q") || !strcmp(arg, "--quiet"))
 			flags |= INIT_DB_QUIET;
 		else

t/t0001-init.sh

@@ -167,4 +167,36 @@ test_expect_success 'init with --template (blank)' '
 	! test -f template-blank/.git/info/exclude
 '
 
+test_expect_success 'init --bare/--shared overrides system/global config' '
+	(
+		HOME="`pwd`" &&
+		export HOME &&
+		test_config="$HOME"/.gitconfig &&
+		unset GIT_CONFIG_NOGLOBAL &&
+		git config -f "$test_config" core.bare false &&
+		git config -f "$test_config" core.sharedRepository 0640 &&
+		mkdir init-bare-shared-override &&
+		cd init-bare-shared-override &&
+		git init --bare --shared=0666
+	) &&
+	check_config init-bare-shared-override true unset &&
+	test x0666 = \
+	x`git config -f init-bare-shared-override/config core.sharedRepository`
+'
+
+test_expect_success 'init honors global core.sharedRepository' '
+	(
+		HOME="`pwd`" &&
+		export HOME &&
+		test_config="$HOME"/.gitconfig &&
+		unset GIT_CONFIG_NOGLOBAL &&
+		git config -f "$test_config" core.sharedRepository 0666 &&
+		mkdir shared-honor-global &&
+		cd shared-honor-global &&
+		git init
+	) &&
+	test x0666 = \
+	x`git config -f shared-honor-global/.git/config core.sharedRepository`
+'
+
 test_done