Fix test: threads being nil in ensure

[pvalena]

Summary

If connection_pool is not installed, then ActiveSupport::Cache.lookup_store(...) fails. The failure gets however overriden by ensure section, with:

MemCacheStoreTest#test_connection_pool:
NoMethodError: undefined method `each' for nil:NilClass
    /builddir/build/BUILD/activesupport-5.2.0/usr/share/gems/gems/activesupport-5.2.0/test/cache/behaviors/connection_pool_behavior.rb:26:in `ensure in block in test_connection$
    /builddir/build/BUILD/activesupport-5.2.0/usr/share/gems/gems/activesupport-5.2.0/test/cache/behaviors/connection_pool_behavior.rb:26:in `block in test_connection_pool'
    /builddir/build/BUILD/activesupport-5.2.0/usr/share/gems/gems/activesupport-5.2.0/test/cache/stores/mem_cache_store_test.rb:124:in `emulating_latency'
    /builddir/build/BUILD/activesupport-5.2.0/usr/share/gems/gems/activesupport-5.2.0/test/cache/behaviors/connection_pool_behavior.rb:7:in `test_connection_pool'

as threads were not declared at that point.

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[matthewd]

Technically I think it should be one more line higher -- above the begin.

More importantly, the same pattern appears 20 lines below, so if we're going to change it, we should do both.

[kamipo]

It is strange, since connection_pool is part of Gemfile.

rails/Gemfile

Line 49 in 21adf4f

gem "connection_pool", require: false

Can you provide how step to reproduce?

[pvalena]

Technically I think it should be one more line higher -- above the begin.

More importantly, the same pattern appears 20 lines below, so if we're going to change it, we should do both.

Sure, will change both.

---

Can you provide how step to reproduce?

Sorry, I forgot to mention, I've encountered this in Fedora, where I'm preparing a rebase to Rails 5.2. We execute the test suite, avoiding bundler, as we package the gems ourselves, like so:

ruby -Ilib:test -e 'Dir.glob "./test/**/*_test.rb", &method(:require)'

The dependency connection_pool was simple not installed, as it was added in 5.2.

[utilum]

The dependency connection_pool was simple not installed, as it was added in 5.2.

Is it needed in master then, or does the problem only arise in earlier versions?

[pvalena]

Is it needed in master then, or does the problem only arise in earlier versions?

It's occurred since Rails 5.2. This is an edge-case, however. Thanks for merging!