python@3.9: make test run on ARM

[claui]

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• Have you checked that there aren't other open pull requests for the same formula update/change?
• Have you built your formula locally with brew install --build-from-source <formula>, where <formula> is the name of the formula you're submitting?
• Is your test running fine brew test <formula>, where <formula> is the name of the formula you're submitting?
• Does your build pass brew audit --strict <formula> (after doing brew install <formula>)?

---

The test block uses the _gdbm module as an example for an external loadable module. That module is not part of the natively built ARM Python though.

Replace _gdbm with _dbm, which is present in either architecture and should serve just the same purpose.

(For the record, _gdbm and _decimal are the only modules that are affected.)

[fxcoudert]

@claui but is it expected that the gdbm and decimal modules are not present? Or is it a build problem? Our formula depends on gdbm so it maybe a configuration issue.

[fxcoudert]

I think we have had trouble with gdbm before, and this is exactly the reason why we put it in the test: to check it is correctly built.

[claui]

@fxcoudert Good points. Need to investigate that.

[digitalresistor]

I know that installing Python from the 3.9 branch (thus 3.9.0 + extra bits) does make gdbm work correctly on arm64.

[fxcoudert]

@TonyWu20 if this is on a supported platform, please file an issue and report all the necessary information

[claui]

Tried to add the gdbm formula’s opt_include but that did not help:

--- a/Formula/python@3.9.rb
+++ b/Formula/python@3.9.rb
@@ -114,7 +114,7 @@ class PythonAT39 < Formula
       --with-openssl=#{Formula["openssl@1.1"].opt_prefix}
     ]
 
-    cflags   = []
+    cflags   = ["-I#{Formula["gdbm"].opt_include}"]
     ldflags  = []
     cppflags = []
 
@@ -151,7 +151,7 @@ class PythonAT39 < Formula
       f.gsub! "DEFAULT_FRAMEWORK_FALLBACK = [", "DEFAULT_FRAMEWORK_FALLBACK = [ '#{HOMEBREW_PREFIX}/Frameworks',"
     end
 
-    args << "CFLAGS=#{cflags.join(" ")}" unless cflags.empty?
+    args << "CFLAGS=#{cflags.join(" ")}"
     args << "LDFLAGS=#{ldflags.join(" ")}" unless ldflags.empty?
     args << "CPPFLAGS=#{cppflags.join(" ")}" unless cppflags.empty?
 
@@ -349,7 +349,6 @@ class PythonAT39 < Formula
     # and it can occur that building sqlite silently fails if OSX's sqlite is used.
     system "#{bin}/python#{xy}", "-c", "import sqlite3"
     # Check if some other modules import. Then the linked libs are working.
-    system "#{bin}/python#{xy}", "-c", "import tkinter; root = tkinter.Tk()"
     system "#{bin}/python#{xy}", "-c", "import _gdbm"
     system "#{bin}/python#{xy}", "-c", "import zlib"
     system bin/"pip3", "list", "--format=columns"

The test still fails:

$ brew test python@3.9
==> Testing python@3.9
==> /opt/homebrew/Cellar/python@3.9/3.9.0_4/bin/python3.9 -c import sqlite3
==> /opt/homebrew/Cellar/python@3.9/3.9.0_4/bin/python3.9 -c import _gdbm
Last 15 lines from /var/brew/Library/Logs/Homebrew/python@3.9/test.02.python3.9:
2020-12-06 16:22:26 +0100

/opt/homebrew/Cellar/python@3.9/3.9.0_4/bin/python3.9
-c
import _gdbm

Traceback (most recent call last):
  File "<string>", line 1, in <module>
ModuleNotFoundError: No module named '_gdbm'
Error: python@3.9: failed
An exception occurred within a child process:
  BuildError: Failed executing: /opt/homebrew/Cellar/python@3.9/3.9.0_4/bin/python3.9 -c import\ _gdbm
/opt/homebrew/Library/Homebrew/formula.rb:2080:in `block in system'
/opt/homebrew/Library/Homebrew/formula.rb:2016:in `open'
/opt/homebrew/Library/Homebrew/formula.rb:2016:in `system'
/opt/homebrew/Library/Taps/homebrew/homebrew-core/Formula/python@3.9.rb:352:in `block in <class:PythonAT39>'
/opt/homebrew/Library/Homebrew/formula.rb:1884:in `block (3 levels) in run_test'
/opt/homebrew/Library/Homebrew/utils.rb:504:in `with_env'
/opt/homebrew/Library/Homebrew/formula.rb:1883:in `block (2 levels) in run_test'
/opt/homebrew/Library/Homebrew/formula.rb:901:in `with_logging'
/opt/homebrew/Library/Homebrew/formula.rb:1882:in `block in run_test'
/opt/homebrew/Library/Homebrew/mktemp.rb:63:in `block in run'
/opt/homebrew/Library/Homebrew/mktemp.rb:63:in `chdir'
/opt/homebrew/Library/Homebrew/mktemp.rb:63:in `run'
/opt/homebrew/Library/Homebrew/formula.rb:2129:in `mktemp'
/opt/homebrew/Library/Homebrew/formula.rb:1876:in `run_test'
/opt/homebrew/Library/Homebrew/test.rb:43:in `block in <main>'
/System/Library/Frameworks/Ruby.framework/Versions/2.6/usr/lib/ruby/2.6.0/timeout.rb:93:in `block in timeout'
/System/Library/Frameworks/Ruby.framework/Versions/2.6/usr/lib/ruby/2.6.0/timeout.rb:33:in `block in catch'
/System/Library/Frameworks/Ruby.framework/Versions/2.6/usr/lib/ruby/2.6.0/timeout.rb:33:in `catch'
/System/Library/Frameworks/Ruby.framework/Versions/2.6/usr/lib/ruby/2.6.0/timeout.rb:33:in `catch'
/System/Library/Frameworks/Ruby.framework/Versions/2.6/usr/lib/ruby/2.6.0/timeout.rb:108:in `timeout'
/opt/homebrew/Library/Homebrew/test.rb:42:in `<main>'

[YilinGUO]

I created this PR to fix the issue #66458. Let me know if that helps. Thanks!

[fxcoudert]

Fixed on #66438