rake compile does not build with the "debug" profile

[nick96]

I've been really enjoying using this rb-sys alongside magnus to write an extension in Rust, thank you!

When developing, I want to build my extension using the "debug" profile for faster compilation times. I tried this from the docs:

create_rust_makefile("rust_reverse") do |r|
  r.profile = ENV.fetch("RB_SYS_CARGO_PROFILE", :dev).to_sym
end

However, the crate is still built in release mode. Looking at the generated Makefile, RB_SYS_CARGO_PROFILE is still always "release". From poking around in the code I think this is because RbSys::Mkmf::Config#rubygems_invoked? returns true due to SOURCE_DATE_EPOCH being set. I'm not 100% but I guess this is being set by rake. I'm using RbSys::ExtensionTask and doing the compilation by rake compile.

[ianks]

Hmmm interesting, SOURCE_DATE_EPOCH being set must be new. Previously, that was the only way to detect if it's rubygems compiling the gem, in which case we don't want to risk accidentally compiling in dev mode.

Does rake compile:dev work?

[nick96]

No, I get the same issue. I'll try to put together an MWE to share

[nick96]

Ah, actually, I can repro this is oxi-test:

$ rake compile:dev
...
generating /Users/nds/Source/oxi-test/target/release/liboxi_test.dylib (release)
cargo rustc  --manifest-path /Users/nds/Source/oxi-test/ext/Cargo.toml --target-dir /Users/nds/Source/oxi-test/target --lib --profile release -- -C linker=clang -L native=/nix/store/sz5lwn6zcmsbg1wyi2vqm6mc4s877wbp-ruby-3.3.6/lib -C link-arg=-Wl,-multiply_defined,suppress -C link-arg=-Wl,-undefined,dynamic_lookup -l pthread
...

With this diff rake compile:dev works as expected (though I don't think this is a solution 😁):

diff --git a/Rakefile b/Rakefile
index da6fd4a..6d6c2c2 100644
--- a/Rakefile
+++ b/Rakefile
@@ -7,6 +7,7 @@ require "minitest/test_task"
 GEMSPEC = Gem::Specification.load('oxi-test.gemspec') || abort('Could not load oxi-test.gemspec')
 
 RbSys::ExtensionTask.new('oxi-test', GEMSPEC) do |ext|
+  ENV.delete('SOURCE_DATE_EPOCH')
   ext.lib_dir = 'lib/oxi/test'
 end

[ianks]

What's your gem env?