Steps to reproduce

Rerun SPACK_PYTHON=python2 SPACK_TEST_SOLVER=clingo spack unit-test -k "installed_externals_are_reused"

It will fail sometimes and succeed other times. This means that all PRs have a random chance of failing CI.

• The test only actually runs when the concretizer is clingo, and otherwise skips
• I'm not yet sure if this also applies to Python 3 but will check that shortly and update here
  • Update: I get this failure about 20% of the time with Python 2 but got no failures in ~30 attempts with Python 3, so I think it is specific to Python 2

Error message

When the test fails:

>       assert external2.dag_hash() != external1.dag_hash()
E       AssertionError: assert 'g2vslm4o3q5wru32m7akp4523tgsyhlt' != 'g2vslm4o3q5wru32m7akp4523tgsyhlt'
E        +  where 'g2vslm4o3q5wru32m7akp4523tgsyhlt' = <bound method Spec.dag_hash of [email protected]%[email protected]+fee+foo arch=test-debian6-core2>()
E        +    where <bound method Spec.dag_hash of [email protected]%[email protected]+fee+foo arch=test-debian6-core2> = [email protected]%[email protected]+fee+foo arch=test-debian6-core2.dag_hash
E        +  and   'g2vslm4o3q5wru32m7akp4523tgsyhlt' = <bound method Spec.dag_hash of [email protected]%[email protected]+fee+foo arch=test-debian6-core2>()
E        +    where <bound method Spec.dag_hash of [email protected]%[email protected]+fee+foo arch=test-debian6-core2> = [email protected]%[email protected]+fee+foo arch=test-debian6-core2.dag_hash

Information on your system

0c6e318 adds a test called test_installed_externals_are_reused

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