Update to Xcode 15.3, prep for Swift concurrency checking (#46)

* Start modernization and concurrency work
* Concurrency warnings in testsuite
* Update CI and misc Xcode settings
* Add locked dictionaries
* Update concurrency discussion

.github/workflows/test.yml

@@ -15,11 +15,12 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        xcode: ['15.2']
-    env:
-      DEVELOPER_DIR: /Applications/Xcode_${{ matrix.xcode }}.app/Contents/Developer
+        xcode: ['15.3']
     steps:
-      - uses: actions/checkout@v2
+      - uses: maxim-lobanov/setup-xcode@v1
+        with:
+          xcode-version: ${{ matrix.xcode }}
+      - uses: actions/checkout@v4
       - name: Ruby
         run: |
           gem install rouge
@@ -65,7 +66,7 @@ jobs:
           - short: '3.3'
             extra_args: '-Xcc -fdeclspec'
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
       - uses: ruby/setup-ruby@v1
         with:
           ruby-version: ${{ matrix.rby.short }}

Makefile

@@ -0,0 +1,14 @@
+.PHONY: all build test
+
+swift_flags := -Xcc -fdeclspec
+
+pwd := $(shell pwd)
+
+all: build
+
+build:
+	PKG_CONFIG_PATH=${pwd}/Packages/CRuby swift build ${swift_flags}
+
+test:
+	PKG_CONFIG_PATH=${pwd}/Packages/CRuby swift test ${swift_flags}
+

Package.swift

@@ -1,4 +1,4 @@
-// swift-tools-version:5.4.0
+// swift-tools-version:5.9
 
 //  Package.swift
 //  RubyGateway
@@ -20,7 +20,12 @@ let package = Package(
     targets: [
         .target(
             name: "RubyGateway",
-            dependencies: ["RubyGatewayHelpers", "CRuby"]),
+            dependencies: ["RubyGatewayHelpers", "CRuby"],
+            swiftSettings: [
+                .enableExperimentalFeature("AccessLevelOnImport"),
+                .enableExperimentalFeature("StrictConcurrency")
+            ]
+        ),
         .target(
             name: "RubyGatewayHelpers",
             dependencies: ["CRuby"]),