bug: `No version is set for command shasum` on Mac

[jlarmstrongiv]

Describe the Bug

In multiple plugins, such as nodejs and python, I get the warning No version is set for command shasum on both x86_64 and arm64 macs where asdf is installed via homebrew.

In some plugins, like nodejs it causes crashes. While I created an issue there asdf-vm/asdf-nodejs#388, the fact that it causes warnings and errors across multiple plugins makes me now think that this is an asdf core error.

Steps to Reproduce

1. On a mac with asdf installed via homebrew
2. Run asdf install nodejs 20.12.1 or asdf install python 3.12.1
3. Notice the warning or error printed to the console

Expected Behaviour

Everything works normally

Actual Behaviour

Warnings or errors are thrown, see asdf-vm/asdf-nodejs#388 for nodejs errors and warnings.

See below for python warning

remote: Enumerating objects: 28, done.
remote: Counting objects: 100% (28/28), done.
remote: Compressing objects: 100% (13/13), done.
remote: Total 28 (delta 11), reused 26 (delta 11), pack-reused 0
Unpacking objects: 100% (28/28), 25.27 KiB | 424.00 KiB/s, done.
From ssh://github.com/pyenv/pyenv
   7deace66..5b4d5a32  master     -> origin/master
python-build 3.12.1 /Users/user/.asdf/installs/python/3.12.1
No version is set for command shasum
Consider adding one of the following versions in your config file at /Users/user/.asdf/.tool-versions
perl 5.32.1
python-build: use openssl@3 from homebrew
python-build: use readline from homebrew
Downloading Python-3.12.1.tar.xz...
-> https://www.python.org/ftp/python/3.12.1/Python-3.12.1.tar.xz
Installing Python-3.12.1...
python-build: use tcl-tk from homebrew
python-build: use readline from homebrew
python-build: use ncurses from homebrew
python-build: use zlib from xcode sdk
Installed Python-3.12.1 to /Users/user/.asdf/installs/python/3.12.1
asdf: Warn: You have configured asdf to preserve downloaded files (with always_keep_download=yes or --keep-download). But
asdf: Warn: the current plugin (python) does not support that. Downloaded files will not be preserved.
  334.53s user 103.07s system 252% cpu 2:53.52 total

Environment

OS:
Darwin user.local 23.3.0 Darwin Kernel Version 23.3.0: Wed Dec 20 21:28:58 PST 2023; root:xnu-10002.81.5~7/RELEASE_X86_64 x86_64

SHELL:
zsh 5.9 (x86_64-apple-darwin23.0)

BASH VERSION:
3.2.57(1)-release

ASDF VERSION:
v0.14.0

ASDF INTERNAL VARIABLES:
ASDF_DEFAULT_TOOL_VERSIONS_FILENAME=.tool-versions
ASDF_DATA_DIR=/Users/jlarmst/.asdf
ASDF_DIR=/usr/local/opt/asdf/libexec
ASDF_CONFIG_FILE=/Users/jlarmst/.asdfrc

ASDF INSTALLED PLUGINS:
golang                       ssh://git@github.com/kennyp/asdf-golang.git master 92a2e61
nodejs                       ssh://git@github.com/asdf-vm/asdf-nodejs.git master c5b7c40
perl                         ssh://git@github.com/ouest/asdf-perl.git main 2b4609b
python                       ssh://git@github.com/danhper/asdf-python.git master 57a4d72
ruby                         ssh://git@github.com/asdf-vm/asdf-ruby.git master f134c2d
rust                         ssh://git@github.com/code-lever/asdf-rust.git master 0c88f99
yarn                         ssh://git@github.com/twuni/asdf-yarn.git main 376c540

OS:
Darwin user.local 23.4.0 Darwin Kernel Version 23.4.0: Fri Mar 15 00:10:42 PDT 2024; root:xnu-10063.101.17~1/RELEASE_ARM64_T6000 arm64

SHELL:
zsh 5.9 (x86_64-apple-darwin23.0)

BASH VERSION:
3.2.57(1)-release

ASDF VERSION:
v0.14.0

ASDF INTERNAL VARIABLES:
ASDF_DEFAULT_TOOL_VERSIONS_FILENAME=.tool-versions
ASDF_DATA_DIR=/Users/jlarmst/.asdf
ASDF_DIR=/opt/homebrew/opt/asdf/libexec
ASDF_CONFIG_FILE=/Users/jlarmst/.asdfrc

ASDF INSTALLED PLUGINS:
nodejs                       ssh://git@github.com/asdf-vm/asdf-nodejs.git master c9e5df4
perl                         ssh://git@github.com/ouest/asdf-perl.git main 2b4609b
python                       ssh://git@github.com/danhper/asdf-python.git master 8505457
rust                         ssh://git@github.com/code-lever/asdf-rust.git master 0c88f99

asdf plugins affected (if relevant)

nodejs
python3