parse_insn_line(): improve error message when parsing failed

In the case that a `get_oid()` call failed, we showed some rather bogus
part of the line instead of the precise string we sent to said function.
That makes it rather hard for users to understand what is going wrong,
so let's fix that.

While at it, return a negative value from `parse_insn_line()` in case of
an error, as per our convention. This function's only caller,
`todo_list_parse_insn_buffer()`, cares only whether that return value is
non-zero or not, i.e. does not need to be changed.

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

Author: dscho

sequencer.c

@@ -2118,18 +2118,19 @@ static int parse_insn_line(struct repository *r, struct todo_item *item,
 	saved = *end_of_object_name;
 	*end_of_object_name = '\0';
 	status = get_oid(bol, &commit_oid);
+	if (status < 0)
+		error(_("could not parse '%s'"), bol); /* return later */
 	*end_of_object_name = saved;
 
 	bol = end_of_object_name + strspn(end_of_object_name, " \t");
 	item->arg_offset = bol - buf;
 	item->arg_len = (int)(eol - bol);
 
 	if (status < 0)
-		return error(_("could not parse '%.*s'"),
-			     (int)(end_of_object_name - bol), bol);
+		return status;
 
 	item->commit = lookup_commit_reference(r, &commit_oid);
-	return !item->commit;
+	return item->commit ? 0 : -1;
 }
 
 int sequencer_get_last_command(struct repository *r, enum replay_action *action)