RE: START_REPLICATION silently truncates an overlong LSN component

Hi Fujii-san,

Thanks for reviewing!

>
> + if (fscanf(lfp,
> + "START WAL LOCATION: %" CppAsString2(MAXPG_LSNLEN)
> "[0-9A-Fa-f/]
> (file %08X%16s)%c",
>
> For portability, isn't it better to use [0123456789ABCDEFabcdef/] instead of
> [0-9A-Fa-f/]? pg_parse_lsn() also lists the hexadecimal digits explicitly.

Done. I checked the C standard and the behavior when - is in the bracket seemed
to be the implementation-defined.

> Since we only need to detect an incremental backup here and don't use
> the LSN value, how about using "%s\n" instead of "[0-9A-Fa-f/]\n"? This would
> preserve the rejection of the above input while also rejecting malformed
> values such as "INCREMENTAL FROM LSN: junk".

Indeed, but %s cannot be used as-is because we need to pass the fixed-length char
array. If we do not have to take care the format of string, isn't it enough to
only check the prefix? I implemented like that in v6.

Best regards,
Hayato Kuroda
FUJITSU LIMITED