Some binary files are inconsistent between different compiles

[EricLin89]

We are using RabbitMQ in a commercial product, which delivers the installation package(with RabbitMQ included) to customer.
So it requires all the binary files in the package are consistent between different compiles, under a given release of source code.

We are compiling RabbitMQ 3.8.14 with erlang 23.0 and Elixir 1.10.4. The compilation process is run inside a chroot environment, which was built by running "yum install basesystem erlang elixir ... ", the yum repos are fixed.

We have a tool for comparing 2 compilation results, and it complains about some binary files are inconsistent. Those are:
Elixir.Collectable.beam
Elixir.CSV.Encode.beam
Elixir.Enumerable.beam
Elixir.IEx.Info.beam
Elixir.Inspect.beam
Elixir.JSON.Decoder.beam
Elixir.JSON.Encoder.beam
Elixir.List.Chars.beam
Elixir.RabbitMQ.CLI.Core.DataCoercion.beam
Elixir.String.Chars.beam
The above files are extracted from "rabbitmqctl" file.

I've made some digging into the makefiles, it seems the make process compiles something from elixir into rabbitmqctl using the "mix" command. But what happens inside "mix" is just beyond my capability.

Another point is this inconsistency only happens when the two compiles are executed on different machines, which is weired because the chroot environment should block the difference of hostos. Also actually the different machines are installed with the same host images.

Acually we have some tools to fix some variables(timestamps, randoms, etc) through the compilation process, but I just don't know where to "fix". Could anyone help to figure it out?

[michaelklishin]

I will convert this issue to a GitHub discussion. Currently GitHub will automatically close and lock the issue even though your question will be transferred and responded to elsewhere. This is to let you know that we do not intend to ignore this but this is how the current GitHub conversion mechanism makes it seem for the users :(

[michaelklishin]

mix is the Elixir build tool. It is not a part of RabbitMQ.

One possible reason can be that the +deterministic Erlang compiler flag or its Elixir compiler equivalent is not used, so environment-specific metadata can make it to the .beam files.

@pjk25 may have more to add.

[HoloRin]

I found this mention of +deterministic with elixir elixir-lang/elixir#8986 but have not yet had a chance to try it out

[EricLin89]

Thanks, I'll give it a try.
Also from the elixir community, I was instructed to check the module_info(), which comes out the "vsn" attributes are different. I'll see what Jose is going to say. elixir-lang/elixir#11249

[HoloRin]

#3440

[HoloRin]

#3442

[EricLin89]

I tried to adopt the changes of deps/rabbitmq_cli/Makefile from #3442. Unfortunately, it didn't work out for me.

[EricLin89]

This issue is solved by elixir-lang/elixir#11249
Thanks for the helpful discussions.