Makefile has race conditions (exposed by -j4)

[gdt]

Elixir and Erlang/OTP versions

Erlang/OTP 25 [erts-13.1.2] [source] [64-bit] [smp:2:2] [ds:2:2:10] [async-threads:1] [jit:ns]

Elixir 1.14.2 (compiled with Erlang/OTP 25)

Operating system

NetBSD 9 and 10, amd64

Current behavior

Running gmake -j4 leads to:

==> bootstrap (compile)
==> eex (compile)
==> mix (compile)
{"init terminating in do_boot",{undef,[{'Elixir.Kernel.CLI',main,[["-e","Mix.start(:permanent, [])","-r","mix.exs","-e","Mix.Task.run(\"compile.app\", ~w[--compile-path ebin])"]],[]},{init,start_em,1,[]},{init,do_boot,3,[]}]}}
init terminating in do_boot ({undef,[{Elixir.Kernel.CLI,main,-eMix.start(:permanent, [])-rmix.exs-eMix.Task.run("compile.app", ~w[--compile-path ebin]),[]},{init,start_em,1,[]},{init,do_boot,3,[]}]})

Crash dump is being written to: erl_crash.dump...done

Without -j, the builds are serialized and work as expected and pass tests. Above, note bootstrap/eex/mix are all started at the same time.

I noticed this in pkgsrc, which is often configured for parallel builds to use multiple CPUs.

Expected behavior

I expect the Makefile to express dependencies and not use build outputs from other rules without waiting.

[josevalim]

Can you please send a PR that makes building the apps serial? Bootstrap and Mix should definitely be serial. You may be able to build the others in parallel.

also the elixir compiler is parallel, so maybe there is not much purpose in using -j.

[josevalim]

Parallel execution has been disabled by adding .NOTPARALLEL:.

[gdt]

Thanks for fixing.