Add IP.Valid?

[Brad Fitzpatrick]

We already have IP.IsZero to test whether an IP is valid, at least if you negate it: !ip.IsZero().

But all the other types have a Valid() bool method:

• IPPort.Valid() bool
• IPPrefix.Valid() bool
• IPRange.Valid() bool

So naturally I reached for IP.Valid and it didn't exist.

Add it?

/cc @mdlayher @danderson @josharian

[Matt Layher]

I like symmetry, go for it.

[Brad Fitzpatrick]

Oh, crap, we named it wrong:

dev:api $ git grep -E 'method.*Valid\('
go1.txt:pkg go/token, method (*Position) IsValid() bool
go1.txt:pkg go/token, method (Pos) IsValid() bool
go1.txt:pkg reflect, method (Value) IsValid() bool
go1.txt:pkg text/scanner, method (*Position) IsValid() bool
go1.txt:pkg text/scanner, method (*Scanner) IsValid() bool

If this is going into std, we should adjust, perhaps earlier.

How about: add IsValid for all 4, but mark the old Valid ones as deprecated so we don't break people's code. But if it moves to std, the Valid ones won't come along.

[Dave Anderson]

SGTM. We could also get rid of Valid here eventually as well, there's relatively few users of the package still.

[Dave Anderson]

(that is, we could fix downstream users then remove Valid)

[Matt Layher]

No objections to API breakage here. Making IPPrefix an opaque type was much more jarring and even that was pretty easy to fix up.