grep: run setup_git_directory_gently() sooner

git grep already runs a repository search unconditionally,
even when the --no-index option is supplied; running such a
search earlier is not very risky.

Just like with shortlog, without this change, the
“[pager] grep” configuration is not respected at all.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/grep.c

@@ -839,7 +839,7 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
 	struct string_list path_list = { NULL, 0, 0, 0 };
 	int i;
 	int dummy;
-	int nongit = 0, use_index = 1;
+	int use_index = 1;
 	struct option options[] = {
 		OPT_BOOLEAN(0, "cached", &cached,
 			"search in index instead of in the work tree"),
@@ -930,8 +930,6 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
 		OPT_END()
 	};
 
-	prefix = setup_git_directory_gently(&nongit);
-
 	/*
 	 * 'git grep -h', unlike 'git grep -h <pattern>', is a request
 	 * to show usage information and exit.
@@ -976,7 +974,7 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
 			     PARSE_OPT_STOP_AT_NON_OPTION |
 			     PARSE_OPT_NO_INTERNAL_HELP);
 
-	if (use_index && nongit)
+	if (use_index && !startup_info->have_repository)
 		/* die the same way as if we did it at the beginning */
 		setup_git_directory();
 

git.c

@@ -336,7 +336,7 @@ static void handle_internal_command(int argc, const char **argv)
 		{ "fsck-objects", cmd_fsck, RUN_SETUP },
 		{ "gc", cmd_gc, RUN_SETUP },
 		{ "get-tar-commit-id", cmd_get_tar_commit_id },
-		{ "grep", cmd_grep },
+		{ "grep", cmd_grep, RUN_SETUP_GENTLY },
 		{ "hash-object", cmd_hash_object },
 		{ "help", cmd_help },
 		{ "index-pack", cmd_index_pack },

t/t7006-pager.sh

@@ -106,6 +106,19 @@ test_expect_success TTY 'no pager with --no-pager' '
 	! test -e paginated.out
 '
 
+test_expect_success TTY 'configuration can disable pager' '
+	rm -f paginated.out &&
+	test_might_fail git config --unset pager.grep &&
+	test_terminal git grep initial &&
+	test -e paginated.out &&
+
+	rm -f paginated.out &&
+	git config pager.grep false &&
+	test_when_finished "git config --unset pager.grep" &&
+	test_terminal git grep initial &&
+	! test -e paginated.out
+'
+
 # A colored commit log will begin with an appropriate ANSI escape
 # for the first color; the text "commit" comes later.
 colorful() {