rebase -i: match whole word in is_command()

When matching an unabbreviated command is_command() only does a prefix
match which means it parses "pickled" as TODO_PICK. parse_insn_line()
does error out because is_command() only advances as far as the end of
"pick" so it looks like the command name is not followed by a space but
the error message is "missing arguments for pick" rather than telling
the user that the "pickled" is not a valid command.

Fix this by ensuring the match is follow by whitespace or the end of the
string as we already do for abbreviated commands. The (*bol = p) at the
end of the condition is a bit cute for my taste but I decided to leave
it be for now. Rather than add new tests the existing tests for bad
commands are adapted to use a bad command name that triggers the prefix
matching bug.

Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

sequencer.c

@@ -2469,12 +2469,11 @@ static int is_command(enum todo_command command, const char **bol)
 {
 	const char *str = todo_command_info[command].str;
 	const char nick = todo_command_info[command].c;
-	const char *p = *bol + 1;
+	const char *p = *bol;
 
-	return skip_prefix(*bol, str, bol) ||
+	return (skip_prefix(p, str, &p) || (nick && *p++ == nick)) &&
-		((nick && **bol == nick) &&
 		(*p == ' ' || *p == '\t' || *p == '\n' || *p == '\r' || !*p) &&
-		 (*bol = p));
+		(*bol = p);
 }
 
 static int parse_insn_line(struct repository *r, struct todo_item *item,
@@ -2503,7 +2502,8 @@ static int parse_insn_line(struct repository *r, struct todo_item *item,
 			break;
 		}
 	if (i >= TODO_COMMENT)
-		return -1;
+		return error(_("invalid command '%.*s'"),
+			     (int)strcspn(bol, " \t\r\n"), bol);
 
 	/* Eat up extra spaces/ tabs before object name */
 	padding = strspn(bol, " \t");

t/lib-rebase.sh

@@ -60,7 +60,7 @@ set_fake_editor () {
 		">")
 			echo >> "$1";;
 		bad)
-			action="badcmd";;
+			action="pickled";;
 		fakesha)
 			test \& != "$action" || action=pick
 			echo "$action XXXXXXX False commit" >> "$1"

t/t3404-rebase-interactive.sh

@@ -1449,14 +1449,15 @@ test_expect_success 'rebase --edit-todo respects rebase.missingCommitsCheck = ig
 
 test_expect_success 'rebase --edit-todo respects rebase.missingCommitsCheck = warn' '
 	cat >expect <<-EOF &&
-	error: invalid line 1: badcmd $(git rev-list --pretty=oneline --abbrev-commit -1 primary~4)
+	error: invalid command '\''pickled'\''
+	error: invalid line 1: pickled $(git rev-list --pretty=oneline --abbrev-commit -1 primary~4)
 	Warning: some commits may have been dropped accidentally.
 	Dropped commits (newer to older):
 	 - $(git rev-list --pretty=oneline --abbrev-commit -1 primary)
 	 - $(git rev-list --pretty=oneline --abbrev-commit -1 primary~4)
 	To avoid this message, use "drop" to explicitly remove a commit.
 	EOF
-	head -n4 expect >expect.2 &&
+	head -n5 expect >expect.2 &&
 	tail -n1 expect >>expect.2 &&
 	tail -n4 expect.2 >expect.3 &&
 	test_config rebase.missingCommitsCheck warn &&
@@ -1467,7 +1468,7 @@ test_expect_success 'rebase --edit-todo respects rebase.missingCommitsCheck = wa
 			git rebase -i --root &&
 		cp .git/rebase-merge/git-rebase-todo.backup orig &&
 		FAKE_LINES="2 3 4" git rebase --edit-todo 2>actual.2 &&
-		head -n6 actual.2 >actual &&
+		head -n7 actual.2 >actual &&
 		test_cmp expect actual &&
 		cp orig .git/rebase-merge/git-rebase-todo &&
 		FAKE_LINES="1 2 3 4" git rebase --edit-todo 2>actual.2 &&
@@ -1483,7 +1484,8 @@ test_expect_success 'rebase --edit-todo respects rebase.missingCommitsCheck = wa
 
 test_expect_success 'rebase --edit-todo respects rebase.missingCommitsCheck = error' '
 	cat >expect <<-EOF &&
-	error: invalid line 1: badcmd $(git rev-list --pretty=oneline --abbrev-commit -1 primary~4)
+	error: invalid command '\''pickled'\''
+	error: invalid line 1: pickled $(git rev-list --pretty=oneline --abbrev-commit -1 primary~4)
 	Warning: some commits may have been dropped accidentally.
 	Dropped commits (newer to older):
 	 - $(git rev-list --pretty=oneline --abbrev-commit -1 primary)
@@ -1583,7 +1585,7 @@ test_expect_success 'static check of bad command' '
 		set_fake_editor &&
 		test_must_fail env FAKE_LINES="1 2 3 bad 4 5" \
 		git rebase -i --root 2>actual &&
-		test_i18ngrep "badcmd $(git rev-list --oneline -1 primary~1)" \
+		test_i18ngrep "pickled $(git rev-list --oneline -1 primary~1)" \
 				actual &&
 		test_i18ngrep "You can fix this with .git rebase --edit-todo.." \
 				actual &&