On Thu, Mar 01, 2018 at 02:17:09PM +0300, Оля Тележная wrote:
> >> I tried to replace all die("...") with `return error("...")` and
> >> finally exit(), but actual problem is that we print "error:..."
> >> instead of "fatal:...", and it looks funny.
> >
> > If you do that, then format_ref_array_item() is still going to print
> > things, even if it doesn't die(). But for "cat-file --batch", we usually
> > do not print errors at all, but instead just say "... missing" (although
> > it depends on the error; syntactic errors in the format string would
> > still cause us to write to stderr).
>
> Not sure if you catch my idea. format_ref_array_item() will not print
> anything, it will just return an error code. And if there was an error
> - we will print it in show_ref_array_item() (or go back to cat-file
> and print what we want).
OK, I think I misunderstood. It seems like there are three possible
strategies on the table:
- low-level functions call error() and return -1, that gets passed up
through mid-level functions like format_ref_array_item(), and then
higher-level functions like show_ref_array_item() act on the error
code and call die(). The user sees something like:
error: unable to parse object 1234abcd
fatal: unable to format object
- low-level functions return a numeric error code, which is then
formatted by higher-level functions like show_ref_array_item() to
produce a specific message
- low-level functions stuff an error code into a strbuf and return -1,
and then higher-level functions like show_ref_array_item() will feed
that message to die("%s", err.buf).
I think the first one, besides changing the output, is going to produce
error() messages even for cases where we're calling
format_ref_array_item() directly, because error() writes its output
immediately.
The second is a pain in practice, because it doubles the work: you have
to come up with a list of error codes, and then translate it them into
strings. And there's no room to mention variable strings (like the name
of the object).
So I think the third is really the only viable option.
-Peff
