2.4.0~rc1

This is the first release candidate of opam 2.4.0.

Binaries and full archive are signed by the opam dev team (fingerprint 92C5 26AE 50DF 3947 0EB2 911B ED4C F1CA 67CB AA92).

Please see our blog post for a highlight on the major changes and upgrade instructions.

Changelog:

Changes

• Fix opam switch create <version> when all compilers of that version are flagged with avoid-version [#6571 @rjbou - fix #6563]
• Opam update performance: No longer copy VCS directories when adding or updating local non-VCS repositories [#6575 @kit-ty-kate - fix #6560]
• Do not remove the generated patch file during updates when debug-mode is on [#6575 @kit-ty-kate]

Release script

• Switch the host of qemu-base-images from gitlab to github [#6510 @kit-ty-kate]
• Speedup the initial clone of qemu-base-images when missing [#6510 @kit-ty-kate]
• Update some of the platforms the prebuilt binaries are built on to Alpine 2.21, FreeBSD 14.3, OpenBSD 7.7 and NetBSD 10.1 [#6510 @kit-ty-kate]

Build changes

• Use coreutils' sha512sum instead of perl's shasum utility when using ./configure --with-cygwin-setup [#6566 @kit-ty-kate - fix #6557]
• Upgrade the download-if-missing dependencies to dune 3.19.1, opam-file-format 2.2.0, spdx_licenses 1.4.0 and patch 3.0.0 [#6580 @kit-ty-kate]

Testing and documentation

• Improve and extend the testsuite [#6473 #6571 @rjbou @kit-ty-kate]
• Improve and extend the test infrastructure [#6575 @kit-ty-kate]

API updates

opam-format

• OpamLocal: fetch_repo_update no longer copies vcs directories [#6575 @kit-ty-kate]

opam-core

• OpamSystem: Add copy_dir_except_vcs [#6575 @kit-ty-kate]
• OpamSystem: Add get_files_except_vcs [#6575 @kit-ty-kate]