base prohibits new Clangs on 10.6 Intel

[barracuda156]

I cannot make the base to pick correct compilers now via blacklist for folly. What I need is clang-15 or later and not clang-11.

The port currently has:

compiler.cxx_standard   2017
compiler.blacklist-append {clang < 1100}
compiler.blacklist-append {macports-clang-[5-9].0}
compiler.blacklist-append macports-gcc-12

On 10.6.8 I get in result:

10:MacPorts-2.9.0 svacchanda$ port deps folly
Full Name: folly @2024.01.22.00_0
Build Dependencies:   cmake, ninja, clang-11, pkgconfig
Library Dependencies: bzip2, double-conversion, gflags, google-glog, libevent,
                      libsodium, libunwind, lz4, lzma, snappy, xz, zlib, zstd,
                      libfmt10, libcxx, boost181, openssl3, legacy-support,
                      macports-libcxx

I thought C++17 will pick a newer clang, but anyway, clang-11 cannot built it, so I try adding:

compiler.blacklist-append {macports-clang-[5-9].0} macports-clang-10 macports-clang-11

And nothing, it still wants clang-11:

10:MacPorts-2.9.0 svacchanda$ port deps folly
Warning: All compilers are either blacklisted or unavailable; defaulting to first fallback option
Full Name: folly @2024.01.22.00_0
Build Dependencies:   cmake, ninja, clang-11, pkgconfig
Library Dependencies: bzip2, double-conversion, gflags, google-glog, libevent,
                      libsodium, libunwind, lz4, lzma, snappy, xz, zlib, zstd,
                      libfmt10, libcxx, boost181, openssl3, legacy-support,
                      macports-libcxx

Only compiler.whitelist macports-clang-16 works:

10:MacPorts-2.9.0 svacchanda$ port deps folly
Full Name: folly @2024.01.22.00_0
Build Dependencies:   cmake, ninja, clang-16, pkgconfig
Library Dependencies: bzip2, double-conversion, gflags, google-glog, libevent,
                      libsodium, libunwind, lz4, lzma, snappy, xz, zlib, zstd,
                      libfmt10, libcxx, boost181, openssl3, legacy-support,
                      macports-libcxx

There is no overriding compiler.blacklist in the portfile, everything is appended.

[kencu (Ken)]

if all the possible compilers are blacklisted:

Warning: All compilers are either blacklisted or unavailable; defaulting to first fallback option

base starts into the fallback compiler list.

You can read about that in portconfigure.tcl

[barracuda156]

Replying to kencu:

if all the possible compilers are blacklisted:

Warning: All compilers are either blacklisted or unavailable; defaulting to first fallback option

base starts into the fallback compiler list.

You can read about that in portconfigure.tcl

Yes, but why are new clangs prohibited for 10.6.8 on x86_64?

[ryandesign (Ryan Carsten Schmidt)]

Replying to barracuda156:

I thought C++17 will pick a newer clang

Per CompilerSelection, C++17 will select Apple clang 10 or later or llvm.org clang 5 or later.

[ryandesign (Ryan Carsten Schmidt)]

Replying to barracuda156:

Yes, but why are new clangs prohibited for 10.6.8 on x86_64?

All the rules are in ​https://github.com/macports/macports-ports/blob/master/_resources/port1.0/compilers/clang_compilers.tcl and ​https://github.com/macports/macports-base/blob/51e0093cf8dad50a0d960566005f91dd5eadcd52/src/port1.0/portconfigure.tcl#L1167; you can read the commit history to discover why they're that way.

[ryandesign (Ryan Carsten Schmidt)]

…by which I don't mean to claim there is a good reason. I haven't tried to read the history to find out. But that's where it could be found for those who want to investigate.

[kencu (Ken)]

clangs newer than about clang-11 fail at times on 10.6.8.

using a newer linker like ld64-latest helps somewhat but macports defaults to ld64-127 on 10.6.8.

and then clang-17+ broke on a bunch of older systems with the verbose_abort issues