pdftk @1.44 +gcc42 won't build on Snow Leopard

[ballapete (Peter "Pete" Dyballa)]

'port variants pdftk' lists:

pdftk has the variants:
   gcc42: Build using gcc42
     * conflicts with gcc45 gcc47
[+]gcc45: Build using gcc45
     * conflicts with gcc42 gcc47
   gcc47: Build using gcc47
     * conflicts with gcc42 gcc45

Since I don't want to have gcc45 or gcc47 I decided to 'port -v install pdftk +gcc42'. This first installs 'fastjar @0.94_0' and then tries to install 'gcc42-4.2.4_7'. The latter fails:

Error: gcc42 does not build on Snow Leopard or later.
Error: org.macports.fetch for port gcc42 returned: unsupported platform

This is already known and reported. Why is 'port variants pdftk' still listing gcc42 as a variant on Snow Leopard?

And why is port not using any of these installed compilers?

port select --list gcc
Available versions for gcc:
	gcc40
	gcc42
	llvm-gcc42
	none (active)

port select --list llvm
Available versions for llvm:
	mp-llvm-3.1
	none (active)

[ryandesign (Ryan Carsten Schmidt)]

Since gcc42 does not work on Snow Leopard anymore, you will need to use either gcc47 or gcc45. pdftk is written in java and requires a java compiler, which is only available in the gcc ports (not in Xcode, not in the clang or llvm-gcc ports).

It's not trivial to add or remove variants from a port based on OS version or other criteria, especially when those variants reference (conflict with) one another. The current behavior is pretty good already in that it does correctly inform you what the problem is.

pdftk will stop offering a gcc42 option; see #34275. gcc42 will be removed from MacPorts entirely; see #33919.