Python upgrade to 3.8.6_2 fails on Big Sur?

[cooperaj]

I'm getting this issue

❯ brew upgrade
Updating Homebrew...
==> Upgrading 1 outdated package:
[email protected] 3.8.6_1 -> 3.8.6_2
==> Upgrading [email protected] 3.8.6_1 -> 3.8.6_2 
Warning: Building [email protected] from source:
  The bottle needs the Apple Command Line Tools to be installed.
  You can install them, if desired, with:
    xcode-select --install

==> Downloading https://files.pythonhosted.org/packages/a7/e0/30642b9c2df516506d40b563b0cbd080c49c6b3f11a70b4c7a670f13a78b/setuptools-50.3.2.zip
Already downloaded: /Users/adamcooper/Library/Caches/Homebrew/downloads/6c4cd84935cccfee61e433509bdda7951ea6b77ae5db203b1e708eea72d93603--setuptools-50.3.2.zip
==> Downloading https://files.pythonhosted.org/packages/0b/f5/be8e741434a4bf4ce5dbc235aa28ed0666178ea8986ddc10d035023744e6/pip-20.2.4.tar.gz
Already downloaded: /Users/adamcooper/Library/Caches/Homebrew/downloads/8420c2f6f4c2831dfbd1b0e1caa05c0c044729c31b52f8884a785a56038ad0e7--pip-20.2.4.tar.gz
==> Downloading https://files.pythonhosted.org/packages/83/72/611c121b6bd15479cb62f1a425b2e3372e121b324228df28e64cc28b01c2/wheel-0.35.1.tar.gz
Already downloaded: /Users/adamcooper/Library/Caches/Homebrew/downloads/1aa1a9563d6af09f2712c180679dfd512aac6c710fc3fb573175e88eaa7c6de3--wheel-0.35.1.tar.gz
==> Downloading https://www.python.org/ftp/python/3.8.6/Python-3.8.6.tar.xz
Already downloaded: /Users/adamcooper/Library/Caches/Homebrew/downloads/8cded16fbf5132bcdeb3125515c30aa484aeb4bdaf7b6886cefcbf129fd47d3d--Python-3.8.6.tar.xz
==> ./configure --prefix=/usr/local/Cellar/[email protected]/3.8.6_2 --enable-ipv6 --datarootdir=/usr/local/Cellar/[email protected]/3.8.6_2/share --datadir=/usr/local/Cellar/[email protected]/3.8.6_2/share --enable-framework=/usr/local/Cellar/[email protected]/3.8.6_2/Fra
==> make
Last 15 lines from /Users/adamcooper/Library/Logs/Homebrew/[email protected]/02.make:
    self.run_command(cmd_name)
  File "/private/tmp/[email protected]/Python-3.8.6/Lib/distutils/cmd.py", line 313, in run_command
    self.distribution.run_command(command)
  File "/private/tmp/[email protected]/Python-3.8.6/Lib/distutils/dist.py", line 985, in run_command
    cmd_obj.run()
  File "/private/tmp/[email protected]/Python-3.8.6/Lib/distutils/command/build_ext.py", line 340, in run
    self.build_extensions()
  File "./setup.py", line 320, in build_extensions
    self.detect_modules()
  File "./setup.py", line 1695, in detect_modules
    self.detect_readline_curses()
  File "./setup.py", line 930, in detect_readline_curses
    (tuple(int(n) for n in dep_target.split('.')[0:2])
AttributeError: 'int' object has no attribute 'split'
make: *** [sharedmods] Error 1

READ THIS: https://docs.brew.sh/Troubleshooting

These open issues may also help:
[email protected]: make test run on ARM https://github.com/Homebrew/homebrew-core/pull/64872

Not sure how to fix this. I've run brew doctor and it found/fixed nothing.

[SMillerDev]

Warning: Building [email protected] from source:
The bottle needs the Apple Command Line Tools to be installed.
You can install them, if desired, with:
xcode-select --install

[cooperaj]

That's the one. I'd overlooked it as i'm doing compliation of other stuff outside of Homebrew without issue - i'd assumed this was just a warning