Re: Enumize logical replication message actions

At Thu, 22 Oct 2020 22:31:41 -0300, Alvaro Herrera  wrote in 
> On 2020-Oct-22, Ashutosh Bapat wrote:
> 
> > On Thu, 22 Oct 2020 at 14:46, Kyotaro Horiguchi 
> > wrote:
> 
> > > pg_send_logicalrep_msg_type() looks somewhat too-much.  If we need
> > > something like that we shouldn't do this refactoring, I think.
> > 
> > Enum is an integer, and we want to send byte. The function asserts that the
> > enum fits a byte. If there's a way to declare byte long enums I would use
> > that. But I didn't find a way to do that.
> 
> I didn't look at the code, but maybe it's sufficient to add a
> StaticAssert?

That check needs to visit all symbols in a enum and confirm that each
of them is in a certain range.

I thought of StaticAssert, but it cannot run a code and I don't know
of a syntax that loops through all symbols in a enumeration so I think
we needs to write a static assertion on every symbol in the
enumeration, which seems to be a kind of stupid.

enum hoge
{
  a = '1',
  b = '2',
  c = '3'
};

StaticAssertDecl((unsigned int)(a | b | c ...) <= 0xff, "too large symbol value");

I didn't come up with a way to apply static assertion on each symbol
definition line.

regards.

-- 
Kyotaro Horiguchi
NTT Open Source Software Center