I am not a maintainer for mmap, and do not know. -- Jack YueCompl writes:

Hi mmap maintainers,

Today I found the last test case out of 25 failed like:

```bash $ cabal v2-run -f mmaptest mmaptest Resolving dependencies... Build profile: -w ghc-8.6.5 -O1 In order, the following will be built (use -v for more details): - mmap-0.5.9 (exe:mmaptest) (configuration changed) Configuring mmap-0.5.9... Preprocessing executable 'mmaptest' for mmap-0.5.9.. Building executable 'mmaptest' for mmap-0.5.9..

<no location info>: warning: [-Wmissing-home-modules] These modules are needed for compilation but not listed in your .cabal file's other-modules: System.IO.MMap

<no location info>: warning: [-Wmissing-home-modules] These modules are needed for compilation but not listed in your .cabal file's other-modules: System.IO.MMap ### Failure in: 24:Counters should be zero tests/mmaptest.hs:256 expected: 0 but got: 4 Cases: 25 Tried: 25 Errors: 0 Failures: 1 ```

And the test code is:

```haskell test_counters_zero = do System.Mem.performGC threadDelay 1000 counters <- c_system_io_counters return (counters @?= 0) ```

I see it is to make sure no resource held open after 1 millisecond after garbage collection is triggered. I tried extending the threadDelay to 10 second and still got 4 thus failing the test, maybe newer machinery of GC with GHC 8.6 should be leveraged to prevent such leakage?

I CC haskell-cafe list to seek for broader community help, maybe some one can confirm that I can just live with this specific failure without worries?

Thanks & best regards, Compl