Upgrade to Big Sur Beta 3 Broke Brew Build system

Question

Today I upgraded to Big Sur Beta3 and I cannot install anything with Brew. I get the error:
Error: Your Xcode (11.6) is too outdated.
Please update to Xcode 12.0 (or delete it).
Xcode can be updated from:
  https://developer.apple.com/download/more/

Error: Could not find an SDK that supports macOS 11.0.
You may have have an outdated or incompatible Xcode.
Homebrew found the following SDKs in the Xcode install:
  10.15

I can safely Ignore first error as I have tried everything I state here with XCode 12 Beta2 yielding the same results. The second one which is actually the issue I get seems to come from name changes that makes this Beta to be 11.0 instead of 10.16.
I have read blog post proposing setting special environment variable and I set as below but still does not work.
export SYSTEM_VERSION_COMPAT=1

Any pointer or help is appreciated

Fernando Montoya · Answer

I fixed it by doing:
sudo xcode-select --switch /Applications/Xcode-beta.app.

James Brickley · Answer

Yep, was broken till I installed Xcode 12.2 Beta 3 / Xcode 12.2 Command line tools Beta 3. Not surprised, this happens every year. I've just received a notification that Xcode Beta 2 Command Line Tools will be automatically installed tonight but I already only have Beta 3 installed.  It's a BETA and it's buggy.
Also, Homebrew's response:
$ brew doctor

Warning: You are using macOS 11.0. We do not provide support for this
pre-release version. You will encounter build failures with some
formulae. Please create pull requests instead of asking for help on
Homebrew's Gihub, Discourse, Twitter or IRC. You are responsible for
resolving any issues you experience while you are running this
pre-release version.

James Robinson · Answer

Same thing happened to me, you need to install the most recent Beta version of command line tools as well as the matching XCode 12 Beta. The same thing also happens with git and other things added by the download https://developer.apple.com/download/more/?=xcode

Answered by James Robinson on December 31, 2021

Upgrade to Big Sur Beta 3 Broke Brew Build system

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