Dev dependencies are written into the app list in .app.src

[Nicd]

See the gleam.toml in https://preview.hex.pm/preview/bigi/3.0.0/show/gleam.toml, gleeunit is only a development dependency. But in the created .app.src, gleeunit is included as a dependency application: https://preview.hex.pm/preview/bigi/3.0.0/show/src/bigi.app.src.

Context: I managed to get bigi compiling in Elixir by putting {:bigi, "~> 3.0", manager: :rebar3} in mix.exs, but trying to run fails due to not having gleeunit. If I edit _build/dev/lib/bigi/ebin/bigi.app and remove gleeunit manually, I can open IEx and run bigi code successfully! :)

zsh/2 486 % iex -S mix
Erlang/OTP 26 [erts-14.1] [source] [64-bit] [smp:20:20] [ds:20:20:10] [async-threads:1] [jit:ns]

Interactive Elixir (1.16.2) - press Ctrl+C to exit (type h() ENTER for help)
iex(1)> :bigi.zero()
0
iex(2)> :bigi.add(1, 2)
3

[Nicd]

The compiler (or rebar3?) also warns

===> "/home/nicd/test/gleam_test/_build/dev/lib/gleam_json/ebin/gleam_json.app" is missing kernel from applications list
===> "/home/nicd/test/gleam_test/_build/dev/lib/gleam_json/ebin/gleam_json.app" is missing stdlib from applications list

and indeed kernel and stdlib are not in the app files. I'm not sure if that's an issue or not.

[Nicd]

I guess this is the place responsible (suitable TODO here 😁):

gleam/compiler-core/src/codegen.rs

Lines 114 to 138 in 55a4e58

	// TODO: When precompiling for production (i.e. as a precompiled hex
	// package) we will need to exclude the dev deps.
	let applications = config
	.dependencies
	.keys()
	.chain(
	config
	.dev_dependencies
	.keys()
	.take_while(|_| self.config.include_dev_deps),
	)
	// TODO: test this!
	.map(|name| self.config.package_name_overrides.get(name).unwrap_or(name))
	.chain(config.erlang.extra_applications.iter())
	.sorted()
	.join(",\n ");
	let text = format!(
	r#"{{application, {package}, [
	{start_module} {{vsn, "{version}"}},
	{{applications, [{applications}]}},
	{{description, "{description}"}},
	{{modules, [{modules}]}},
	{{registered, []}}
	]}}.

[Nicd]

Whether dev deps are included is controlled by this line:

gleam/compiler-core/src/build/project_compiler.rs

Line 520 in 55a4e58

include_dev_deps: is_root,

We could turn it to false there, but I suppose that would break functionality if the user wants some app to exist in development but not in production (like phoenix_live_reload type things)? So do we need a dev/prod distinction to proceed with this issue?

[Acepie]

Would it ever make sense to include dev deps in prod? Cause the project compiler already has the mode for dev vs prod so unless there is a reason we would want to keep dev deps in prod we could always update that line to check mode != Mode::Prod instead since dependencies are all compiled in prod mode already

[Nicd]

But, do we ever use the prod mode? I was under the impression that we don't have prod builds. That's what I meant by having a dev/prod distinction, i.e. do we need to start using prod builds?

A lighter alternative could be to detect when building for Hex upload and not including dev deps then?

[Acepie]

Yeah there are a couple places where the compiler looks at the mode to determine what to do though i know for javascript generation specifically it ignores the mode. For example https://github.com/gleam-lang/gleam/blob/main/compiler-core/src/build/package_loader.rs#L214 the package loader doesn't load test modules in prod. This seems like it would fall under the same category?

[Nicd]

Hmm, I guess I'll try it out and see. 👍

[Nicd]

I made this change:

diff --git a/compiler-core/src/build/project_compiler.rs b/compiler-core/src/build/project_compiler.rs
index de2f2006..79eea3d6 100644
--- a/compiler-core/src/build/project_compiler.rs
+++ b/compiler-core/src/build/project_compiler.rs
@@ -517,7 +517,7 @@ where
                     .collect();
                 super::TargetCodegenConfiguration::Erlang {
                     app_file: Some(ErlangAppCodegenConfiguration {
-                        include_dev_deps: is_root,
+                        include_dev_deps: self.mode() != Mode::Prod,
                         package_name_overrides,
                     }),
                 }

After running gleam publish and canceling it, this file is created in build/prod/erlang/bigi/ebin/bigi.app:

{application, bigi, [
    {vsn, "3.0.0"},
    {applications, [gleam_stdlib]},
    {description, "Arbitrary precision integer arithmetic for Gleam"},
    {modules, [bigi]},
    {registered, []}
]}.

After running just gleam build, this file is created in build/dev/erlang/bigi/ebin/bigi.app:

{application, bigi, [
    {vsn, "3.0.0"},
    {applications, [gleam_stdlib,
                    gleeunit]},
    {description, "Arbitrary precision integer arithmetic for Gleam"},
    {modules, [bigi,
               bigi_test]},
    {registered, []}
]}.

So it seems to work. Is there something specific I should test? This does not seem to be tested directly as the only mention of include_dev_deps has it hardcoded in the tests and all the tests pass with the change.

[lpil]

It'd be good to have a test for the contents of the Hex tarball if that's something we don't already have.

[Nicd]

There is a test-package-compiler, but it forces include_dev_deps: true.