build(crossruby): pass host dump_ast when supported

Detect whether the Ruby source supports --with-dump-ast and pass the host-built dump_ast alongside --with-baseruby for cross builds. This fixes ruby-head-wasm-wasi builds on current Ruby head while avoiding configure failures on older Ruby versions.

Author: ledsun

lib/ruby_wasm/build/product/crossruby.rb

@@ -322,6 +322,10 @@ def baseruby_path
       File.join(@baseruby.install_dir, "bin/ruby")
     end
 
+    def dump_ast_path
+      File.join(@baseruby.product_build_dir, "dump_ast")
+    end
+
     def configure_args(build_triple, toolchain)
       target = @params.target.triple
       default_exts = @params.default_exts
@@ -336,6 +340,7 @@ def configure_args(build_triple, toolchain)
       args << %Q(--with-zlib-dir=#{@zlib.install_root})
       args << %Q(--with-openssl-dir=#{@openssl.install_root}) if @openssl
       args << %Q(--with-baseruby=#{baseruby_path})
+      args << %Q(--with-dump-ast=#{dump_ast_path}) if @source.supports_with_dump_ast?
 
       case target
       when /^wasm32-unknown-wasi/

lib/ruby_wasm/build/product/ruby_source.rb

@@ -33,6 +33,12 @@ def configure_file
       File.join(src_dir, "configure")
     end
 
+    def supports_with_dump_ast?
+      [File.join(src_dir, "configure.ac"), configure_file].any? do |path|
+        File.file?(path) && File.read(path).include?("--with-dump-ast")
+      end
+    end
+
     def fetch(executor)
       case @params[:type]
       when "github"

test/test_crossruby_configure_args.rb

@@ -0,0 +1,96 @@
+require "test-unit"
+require "tmpdir"
+require "fileutils"
+require_relative "../lib/ruby_wasm/build"
+require_relative "../lib/ruby_wasm/build/product/ruby_source"
+require_relative "../lib/ruby_wasm/build/product/crossruby"
+
+class TestCrossRubyConfigureArgs < Test::Unit::TestCase
+  FakeProduct = Struct.new(:install_root, :install_dir, :product_build_dir)
+  FakeToolchain =
+    Struct.new(
+      :cc,
+      :cxx,
+      :ld,
+      :ar,
+      :ranlib,
+      :wasm_opt,
+      :wasi_sdk_path,
+      keyword_init: true
+    )
+
+  def setup
+    @toolchain =
+      FakeToolchain.new(
+        cc: "clang",
+        cxx: "clang++",
+        ld: "wasm-ld",
+        ar: "llvm-ar",
+        ranlib: "llvm-ranlib",
+        wasm_opt: "wasm-opt",
+        wasi_sdk_path: "/opt/wasi-sdk"
+      )
+  end
+
+  def build_crossruby(tmpdir, configure_contents:)
+    source =
+      RubyWasm::BuildSource.new(
+        {
+          name: "head",
+          type: "local",
+          path: tmpdir,
+        },
+        tmpdir
+      )
+    FileUtils.mkdir_p(source.src_dir)
+    File.write(File.join(source.src_dir, "configure.ac"), configure_contents)
+
+    params =
+      RubyWasm::BuildParams.new(
+        name: "ruby-head-wasm-wasi",
+        target: RubyWasm::Target.new("wasm32-unknown-wasip1"),
+        default_exts: "json"
+      )
+    baseruby = FakeProduct.new(nil, "/tmp/baseruby/opt", "/tmp/baseruby/build")
+    crossruby =
+      RubyWasm::CrossRubyProduct.new(
+        params,
+        File.join(tmpdir, "build"),
+        File.join(tmpdir, "rubies"),
+        baseruby,
+        source,
+        @toolchain
+      )
+    crossruby.with_libyaml(FakeProduct.new("/tmp/libyaml"))
+    crossruby.with_zlib(FakeProduct.new("/tmp/zlib"))
+    crossruby
+  end
+
+  def test_configure_args_include_dump_ast_when_supported
+    Dir.mktmpdir do |tmpdir|
+      crossruby =
+        build_crossruby(
+          tmpdir,
+          configure_contents: "AC_ARG_WITH(dump-ast,\n  AS_HELP_STRING([--with-dump-ast=DUMP_AST], []))"
+        )
+
+      args = crossruby.configure_args("x86_64-linux-gnu", @toolchain)
+
+      assert_include args, "--with-dump-ast=/tmp/baseruby/build/dump_ast"
+    end
+  end
+
+  def test_configure_args_skip_dump_ast_when_unsupported
+    Dir.mktmpdir do |tmpdir|
+      crossruby =
+        build_crossruby(
+          tmpdir,
+          configure_contents: "AC_ARG_WITH(baseruby,\n  AS_HELP_STRING([--with-baseruby=BASERUBY], []))"
+        )
+
+      args = crossruby.configure_args("x86_64-linux-gnu", @toolchain)
+
+      assert_not_include args.grep(/\A--with-dump-ast=/), "--with-dump-ast=/tmp/baseruby/build/dump_ast"
+    end
+  end
+end