[swift-dev] Building swift-3.1-branch from source

[Ian Partridge]

Hi, I'm trying to build a toolchain from swift-3.1-branch on Linux.

I cloned https://github.com/apple/swift and ran
"./swift/utils/update-checkout --clone" successfully.

Then, for each subdirectory (swift, swift-corelibs-foundation, lldb,
llvm etc.) I switched to swift-3.1-branch via "git checkout
swift-3.1-branch".

Then I ran:

./swift/utils/build-script --preset=buildbot_linux
install_destdir=/home/ipartrid/swift-3.1
installable_package=/home/ipartrid/swift-3.1.tar.gz

But this fails with:

Traceback (most recent call last):
  File "./swift/utils/build-script", line 27, in <module>
    from SwiftBuildSupport import (
  File "/home/ipartrid/swift-source/swift/utils/SwiftBuildSupport.py",
line 26, in <module>
    from swift_build_support import diagnostics  # noqa (E402)
ImportError: cannot import name diagnostics

Can anyone advise on how to build swift-3.1-branch?  I'm pretty sure
my procedure above used to work, until recently.

Many thanks,

-- 
Ian Partridge