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 Djukic <[email protected]>
Signed-off-by: Johannes Schindelin <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: dscho

add-interactive.c

@@ -428,6 +428,27 @@ 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 *ps,
+		    struct file_list *files, struct list_options *opts)
+{
+	const char *help_color = s->help_color;
+
+	color_fprintf_ln(stdout, help_color, "status        - %s",
+			 _("show paths with changes"));
+	color_fprintf_ln(stdout, help_color, "update        - %s",
+			 _("add working tree state to the staged set of changes"));
+	color_fprintf_ln(stdout, help_color, "revert        - %s",
+			 _("revert staged set of changes back to the HEAD version"));
+	color_fprintf_ln(stdout, help_color, "patch         - %s",
+			 _("pick hunks and update selectively"));
+	color_fprintf_ln(stdout, help_color, "diff          - %s",
+			 _("view diff between HEAD and index"));
+	color_fprintf_ln(stdout, help_color, "add untracked - %s",
+			 _("add contents of untracked files to the staged set of changes"));
+
+	return 0;
+}
+
 struct print_command_item_data {
 	const char *color, *reset;
 };
@@ -473,9 +494,11 @@ int run_add_i(struct repository *r, const struct pathspec *ps)
 		N_("What now"), command_prompt_help
 	};
 	struct command_item
-		status = { { "status" }, run_status };
+		status = { { "status" }, run_status },
+		help = { { "help" }, run_help };
 	struct command_item *commands[] = {
-		&status
+		&status,
+		&help
 	};
 
 	struct print_file_item_data print_file_item_data = {

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