"self.run_tests" attribute masked by the object wrapper

[alalazo]

Steps to reproduce

Originally reported by @rbberger in https://spackpm.slack.com/archives/C5VL7V81G/p1669578286178559

Classes that try to use self.run_tests to set any custom attribute and are not using builders will see this attribute set to False due to the object wrapper.

Error message

No error message, just unexpected behavior.

Information on your system

• Spack: 0.20.0.dev0 (e030833)
• Python: 3.8.10
• Platform: linux-ubuntu20.04-icelake
• Concretizer: clingo

General information

• I have run spack debug report and reported the version of Spack/Python/Platform
• I have searched the issues of this repo and believe this is not a duplicate
• I have run the failing commands in debug mode and reported the output

[tvandera]

I was trying to reproduce this problem on my macbook, and for some reason it seems to work fine on macOS. Shall I try to make a reproducible example?

[tvandera]

This simple example works on macOS and fails on Linux:

class RunTestsTest(Package):
    """Test Package"""

    homepage = "http://example.com"
    url      = "https://downloads.sourceforge.net/project/bowtie-bio/bowtie/1.2.1.1/bowtie-1.2.1.1-src.zip"
    version('1.2.1.1', 'ec06265730c5f587cd58bcfef6697ddf')

    def install(self, spec, prefix):
        print("run_tests = ", self.run_tests)
        assert False

On Linux:

$ spack -vd install --test=root run-tests-test 2>&1 | grep -A1 run_test
run_tests =  False
==> [2022-12-14-15:11:47.854487] Error: AssertionError:
--
          9        print("run_tests = ", self.run_tests)
  >>     10        assert False
(base) [/scratch/vanderaa]
 $ spack-python --version
Python 3.10.6
$ spack --version
0.20.0.dev0 (eec09f791d320c6ba73be0a71a8f0e0f4355a31c)

On macOS:

 $ spack -vd install --test=root run-tests-test 2>&1 | grep -A1 run_tests
run_tests =  True
==> [2022-12-14-14:37:46.526235] Error: AssertionError:
--
          9        print("run_tests = ", self.run_tests)
  >>     10        assert False
 $ spack-python --version
Python 3.10.8
$ spack --version
0.20.0.dev0 (9fdb36585f083133232686015903c022ea653980)

[alalazo]

The issue is due to this line:

spack/lib/spack/spack/installer.py

Line 1276 in 55356e9

pkg.run_tests = tests is True or tests and pkg.name in tests

which monkey patches an object that was used, before monkey patching, to create and cache a builder. The wrapping is done here:

spack/lib/spack/spack/builder.py

Line 130 in 55356e9

self.__dict__.update(wrapped_pkg_object.__dict__)

[alalazo]

On the difference between macOS and linux, those are likely due to the different strategies used to create the separate process to install a spec. On macOS we use spawn which doesn't create an entire in memory copy of the current process, on linux we use fork.