On Fri, Mar 27, 2020 at 02:58:38PM -0700, Junio C Hamano wrote:
> Patrick Steinhardt <ps@xxxxxx> writes:
>
> > static const struct parse_cmd {
> > const char *prefix;
> > - const char *(*fn)(struct ref_transaction *, const char *, const char *);
> > + void (*fn)(struct ref_transaction *, const char *, const char *);
> > + unsigned extra_lines;
>
> Define and explain the meaning of extra_lines in a comment. Without
> it, the most natural way to infer what the variable means by readers
> would be that "update" command sometimes receives up to two more
> lines but it also is perfectly normal if there is no extra line.
>
> But I am not sure if that is what is going on.
>
> "update" _always_ needs exactly two more input "lines" when the
> input is NUL delimited, perhaps, and it is an _error_ if there are
> not these two lines, no?
That's extactly right. I pondered on a good name, but I wasn't yet able
to come up with any one that brings across its meaning. I originally had
`extra_args` but changed it after some internal discussion with Chris.
> The name of the field should make such details clear.
>
> > } commands[] = {
> > - { "update", parse_cmd_update },
> > - { "create", parse_cmd_create },
> > - { "delete", parse_cmd_delete },
> > - { "verify", parse_cmd_verify },
> > - { "option", parse_cmd_option },
> > + { "update", parse_cmd_update, 2 },
> > + { "create", parse_cmd_create, 1 },
> > + { "delete", parse_cmd_delete, 1 },
> > + { "verify", parse_cmd_verify, 1 },
> > + { "option", parse_cmd_option, 0 },
> > };
> > + /* Read extra lines if NUL-terminated */
> > + for (j = 0; line_termination == '\0' && j < cmd->extra_lines; j++)
> > + if (strbuf_appendwholeline(&input, stdin, line_termination))
> > + break;
>
> And this code does not barf if you get a premature EOF and let the
> call to cmd->fn() go through, which sounds buggy.
This is in fact by design, but I only change the comment in a later
commit. The reasoning is that by passing even incomplete buffers to a
command, the command is going to be able to print a much better error
message than printing a generic one here.
I'll make sure to move over the comment.
Patrick
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