Fails when the brew command is not available

[S-zebra]

Distutils tries to get the output of brew --prefix, but it fails if Homebrew is not installed on the system, or when brew command is not available.

distutils/distutils/command/_framework_compat.py

Line 42 in 152c13d

homebrew_prefix = subprocess.check_output(['brew', '--prefix'], text=True).strip()

[dflems]

See also #159 and #155 (comment)

@jaraco

[jaraco]

At first, I was going to use this diff:

diff --git a/distutils/command/_framework_compat.py b/distutils/command/_framework_compat.py
index e032603..c2849a1 100644
--- a/distutils/command/_framework_compat.py
+++ b/distutils/command/_framework_compat.py
@@ -7,6 +7,7 @@ import sys
 import os
 import functools
 import subprocess
+import contextlib
 
 
 @functools.lru_cache()
@@ -39,7 +40,10 @@ schemes = dict(
 def vars():
     if not enabled():
         return {}
-    homebrew_prefix = subprocess.check_output(['brew', '--prefix'], text=True).strip()
+    with contextlib.suppress(FileNotFoundError):
+        homebrew_prefix = subprocess.check_output(
+            ['brew', '--prefix'], text=True
+        ).strip()
     return locals()

But then I realized that will only cause a different error because {homebrew_prefix} will be in the scheme but undefined. The enabled() function needs to detect whether the install is a homebrew one.

[jaraco]

Maybe the presence of "Cellar" in the projectbase config var is a good indicator?

>>> pprint.pprint({k:v for k, v in sysconfig.get_config_vars().items() if isinstance(v, str) and 'Cellar' in v})
{'projectbase': '/opt/homebrew/Cellar/python@3.10/3.10.5/Frameworks/Python.framework/Versions/3.10/bin',
 'srcdir': '/opt/homebrew/Cellar/python@3.10/3.10.5/Frameworks/Python.framework/Versions/3.10/lib/python3.10/config-3.10-darwin'}

[jaraco]

Fix is rolling out is 63.2.0.

[carlocab]

You can have "Cellar" in sysconfig.get_config_var('projectbase') return True but have the call to brew still return an error because brew is not in your PATH.

You might want to do this, for instance, when you wish to isolate a build from the contents of $(brew --prefix)/bin.