Add Config#use_cargo_build: (#337)

* Add Config#use_cargo_build:

This switches behaviour to use `cargo build` instead of `cargo rustc`,
which has the effect of sharing cache better with `cargo build`, but
requires setting rb_sys environment in the default build.

* fmt

.github/workflows/integration.yml

@@ -34,14 +34,14 @@ jobs:
         ruby: ["2.7", "3.2", "3.3"]
         exclude:
           - os: windows-latest
-            ruby: '3.3' # remove this once 3.3 binaries are available for windows
+            ruby: "3.3" # remove this once 3.3 binaries are available for windows
             repo:
               name: "matsadler/magnus"
               slug: magnus-head
               ref: "05359fcd2369f014570f1e417c7c2d462625af5e"
               run: cargo test
           - os: windows-latest
-            ruby: '3.3' # remove this once 3.3 binaries are available for windows
+            ruby: "3.3" # remove this once 3.3 binaries are available for windows
             repo:
               name: "matsadler/magnus"
               slug: magnus-0.5

CONTRIBUTING.md

@@ -31,8 +31,7 @@ make contribution easier. Here are the steps to use it:
 
 ## Running benchmarks
 
-To run the benchmarks, make sure your dev environment, then run `cargo bench`.
-This will run the `criterion` benchmarks and print the results to the console.
+To run the benchmarks, make sure your dev environment, then run `cargo bench`. This will run the `criterion` benchmarks
+and print the results to the console.
 
-To see see plots of the results, you can open
-`target/criterion/report/index.html` in your browser.
+To see see plots of the results, you can open `target/criterion/report/index.html` in your browser.

gem/lib/rb_sys/cargo_builder.rb

@@ -9,7 +9,7 @@ class CargoBuilder < Gem::Ext::Builder
     WELL_KNOWN_WRAPPERS = %w[sccache cachepot].freeze
 
     attr_accessor :spec, :runner, :env, :features, :target, :extra_rustc_args, :dry_run, :ext_dir, :extra_rustflags,
-      :extra_cargo_args
+      :extra_cargo_args, :config
     attr_writer :profile
 
     def initialize(spec)
@@ -66,17 +66,23 @@ def manifest_dir
 
     def cargo_command(dest_path, args = [])
       cmd = []
-      cmd += ["cargo", "rustc"]
+      cmd += if config.use_cargo_build
+        ["cargo", "build"]
+      else
+        ["cargo", "rustc"]
+      end
       cmd += ["--target", target] if target
       cmd += ["--target-dir", dest_path]
       cmd += ["--features", features.join(",")] unless features.empty?
       cmd += ["--lib"]
       cmd += ["--profile", profile.to_s]
       cmd += Gem::Command.build_args
       cmd += args
-      cmd += ["--"]
-      cmd += [*rustc_args(dest_path)]
-      cmd += extra_rustc_args
+      if !config.use_cargo_build
+        cmd += ["--"]
+        cmd += [*rustc_args(dest_path)]
+        cmd += extra_rustc_args
+      end
       cmd
     end
 

gem/lib/rb_sys/mkmf.rb

@@ -10,9 +10,6 @@
 module RbSys
   # Helper class for creating Rust Makefiles
   module Mkmf
-    # @api private
-    GLOBAL_RUSTFLAGS = ["--cfg=rb_sys_gem"]
-
     # Helper for building Rust extensions by creating a Ruby compatible makefile
     # for Rust. By using this class, your rust extension will be 100% compatible
     # with the rake-compiler gem, which allows for easy cross compilation.
@@ -53,7 +50,9 @@ def create_rust_makefile(target, &blk)
       RbConfig.expand(srcdir = srcprefix.dup)
 
       full_cargo_command = cargo_command(srcdir, builder)
-      global_rustflags = GLOBAL_RUSTFLAGS.dup
+
+      global_rustflags = []
+      global_rustflags << "--cfg=rb_sys_gem" unless builder.use_cargo_build
       global_rustflags << "--cfg=rb_sys_use_stable_api_compiled_fallback" if builder.use_stable_api_compiled_fallback?
 
       make_install = +<<~MAKE
@@ -169,7 +168,11 @@ def cargo_command(cargo_dir, builder)
       cargo_cmd = builder.cargo_command(dest_path, args)
       cmd = Shellwords.join(cargo_cmd)
       cmd.gsub!("\\=", "=")
-      cmd.gsub!(/\Acargo rustc/, "$(CARGO) rustc $(RB_SYS_EXTRA_CARGO_ARGS) --manifest-path $(RB_SYS_CARGO_MANIFEST_DIR)/Cargo.toml")
+      if builder.use_cargo_build
+        cmd.gsub!(/\Acargo rustc/, "$(CARGO) build $(RB_SYS_EXTRA_CARGO_ARGS) --manifest-path $(RB_SYS_CARGO_MANIFEST_DIR)/Cargo.toml")
+      else
+        cmd.gsub!(/\Acargo rustc/, "$(CARGO) rustc $(RB_SYS_EXTRA_CARGO_ARGS) --manifest-path $(RB_SYS_CARGO_MANIFEST_DIR)/Cargo.toml")
+      end
       cmd.gsub!(/-v=\d/, "")
       cmd
     end

gem/lib/rb_sys/mkmf/config.rb

@@ -25,8 +25,13 @@ class Config
       # Use compiled C code fallback for stable API for ruby-head (default: false)
       attr_accessor :use_stable_api_compiled_fallback
 
+      # Instead of the default `cargo rustc` behaviour, just call `cargo build`.
+      # Requires manually setting relevant rb-sys environment (default: false)
+      attr_accessor :use_cargo_build
+
       def initialize(builder)
         @builder = builder
+        @builder.config = self
         @force_install_rust_toolchain = false
         @auto_install_rust_toolchain = true
         @use_stable_api_compiled_fallback = false

readme.md

@@ -17,7 +17,8 @@ it's not easy, it's a bug.
 
 ## New to `rb-sys`?
 
-- [Ruby on Rust Book 📖](https://oxidize-rb.github.io/rb-sys/) to describe how to build, test, and deploy a Rusty Ruby Gem
+- [Ruby on Rust Book 📖](https://oxidize-rb.github.io/rb-sys/) to describe how to build, test, and deploy a Rusty Ruby
+  Gem
 - [Contributing Docs 💻](./CONTRIBUTING.md) to get started in making your first contributions to rb-sys
 - [`rb-sys` gem 💎](./gem/README.md) to learn more about the `rb-sys` gem for **compiling extensions**
 
@@ -58,14 +59,14 @@ directory for automation purposes):
 
 | Platform          | Supported | Docker Image                                   |
 | ----------------- | --------- | ---------------------------------------------- |
-| x86_64-linux      | ✅         | [`rbsys/x86_64-linux:0.9.89`][docker-hub]      |
-| x86_64-linux-musl | ✅         | [`rbsys/x86_64-linux-musl:0.9.89`][docker-hub] |
-| aarch64-linux     | ✅         | [`rbsys/aarch64-linux:0.9.89`][docker-hub]     |
-| arm-linux         | ✅         | [`rbsys/arm-linux:0.9.89`][docker-hub]         |
-| arm64-darwin      | ✅         | [`rbsys/arm64-darwin:0.9.89`][docker-hub]      |
-| x64-mingw32       | ✅         | [`rbsys/x64-mingw32:0.9.89`][docker-hub]       |
-| x64-mingw-ucrt    | ✅         | [`rbsys/x64-mingw-ucrt:0.9.89`][docker-hub]    |
-| mswin             | ✅         | not available on Docker                        |
+| x86_64-linux      | ✅        | [`rbsys/x86_64-linux:0.9.89`][docker-hub]      |
+| x86_64-linux-musl | ✅        | [`rbsys/x86_64-linux-musl:0.9.89`][docker-hub] |
+| aarch64-linux     | ✅        | [`rbsys/aarch64-linux:0.9.89`][docker-hub]     |
+| arm-linux         | ✅        | [`rbsys/arm-linux:0.9.89`][docker-hub]         |
+| arm64-darwin      | ✅        | [`rbsys/arm64-darwin:0.9.89`][docker-hub]      |
+| x64-mingw32       | ✅        | [`rbsys/x64-mingw32:0.9.89`][docker-hub]       |
+| x64-mingw-ucrt    | ✅        | [`rbsys/x64-mingw-ucrt:0.9.89`][docker-hub]    |
+| mswin             | ✅        | not available on Docker                        |
 
 ## Getting Help