built-in add -i: implement the `help` command

This imitates the code to show the help text from the Perl script
`git-add--interactive.perl` in the built-in version.

To make sure that it renders exactly like the Perl version of `git add
-i`, we also add a test case for that to `t3701-add-interactive.sh`.

Signed-off-by: Slavica Đukić <slawica92@hotmail.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

2 files changed, 46 insertions, 0 deletions

diff --git a/add-interactive.c b/add-interactive.c
index 170a5800e3..d6cb98cd40 100644
--- a/add-interactive.c
+++ b/add-interactive.c
@@ -508,6 +508,26 @@ static int run_status(struct add_i_state *s, const struct pathspec *ps,
 	return 0;
 }
 
+static int run_help(struct add_i_state *s, const struct pathspec *unused_ps,
+		    struct string_list *unused_files,
+		    struct list_options *unused_opts)
+{
+	color_fprintf_ln(stdout, s->help_color, "status        - %s",
+			 _("show paths with changes"));
+	color_fprintf_ln(stdout, s->help_color, "update        - %s",
+			 _("add working tree state to the staged set of changes"));
+	color_fprintf_ln(stdout, s->help_color, "revert        - %s",
+			 _("revert staged set of changes back to the HEAD version"));
+	color_fprintf_ln(stdout, s->help_color, "patch         - %s",
+			 _("pick hunks and update selectively"));
+	color_fprintf_ln(stdout, s->help_color, "diff          - %s",
+			 _("view diff between HEAD and index"));
+	color_fprintf_ln(stdout, s->help_color, "add untracked - %s",
+			 _("add contents of untracked files to the staged set of changes"));
+
+	return 0;
+}
+
 typedef int (*command_t)(struct add_i_state *s, const struct pathspec *ps,
 			 struct string_list *files,
 			 struct list_options *opts);
@@ -561,6 +581,7 @@ int run_add_i(struct repository *r, const struct pathspec *ps)
 		command_t command;
 	} command_list[] = {
 		{ "status", run_status },
+		{ "help", run_help },
 	};
 	struct prefix_item_list commands = PREFIX_ITEM_LIST_INIT;
 
diff --git a/t/t3701-add-interactive.sh b/t/t3701-add-interactive.sh
index d50e165ca8..d4f9386621 100755
--- a/t/t3701-add-interactive.sh
+++ b/t/t3701-add-interactive.sh
@@ -647,4 +647,29 @@ test_expect_success 'checkout -p works with pathological context lines' '
 	test_write_lines a b a b a a b a b a >expect &&
 	test_cmp expect a
 '
+
+test_expect_success 'show help from add--helper' '
+	git reset --hard &&
+	cat >expect <<-EOF &&
+
+	<BOLD>*** Commands ***<RESET>
+	  1: <BOLD;BLUE>s<RESET>tatus	  2: <BOLD;BLUE>u<RESET>pdate	  3: <BOLD;BLUE>r<RESET>evert	  4: <BOLD;BLUE>a<RESET>dd untracked
+	  5: <BOLD;BLUE>p<RESET>atch	  6: <BOLD;BLUE>d<RESET>iff	  7: <BOLD;BLUE>q<RESET>uit	  8: <BOLD;BLUE>h<RESET>elp
+	<BOLD;BLUE>What now<RESET>> <BOLD;RED>status        - show paths with changes<RESET>
+	<BOLD;RED>update        - add working tree state to the staged set of changes<RESET>
+	<BOLD;RED>revert        - revert staged set of changes back to the HEAD version<RESET>
+	<BOLD;RED>patch         - pick hunks and update selectively<RESET>
+	<BOLD;RED>diff          - view diff between HEAD and index<RESET>
+	<BOLD;RED>add untracked - add contents of untracked files to the staged set of changes<RESET>
+	<BOLD>*** Commands ***<RESET>
+	  1: <BOLD;BLUE>s<RESET>tatus	  2: <BOLD;BLUE>u<RESET>pdate	  3: <BOLD;BLUE>r<RESET>evert	  4: <BOLD;BLUE>a<RESET>dd untracked
+	  5: <BOLD;BLUE>p<RESET>atch	  6: <BOLD;BLUE>d<RESET>iff	  7: <BOLD;BLUE>q<RESET>uit	  8: <BOLD;BLUE>h<RESET>elp
+	<BOLD;BLUE>What now<RESET>>$SP
+	Bye.
+	EOF
+	test_write_lines h | GIT_PAGER_IN_USE=true TERM=vt100 git add -i >actual.colored &&
+	test_decode_color <actual.colored >actual &&
+	test_i18ncmp expect actual
+'
+
 test_done