Add support for configuration cache (#153)

Author: nedtwigg

CHANGES.md

@@ -1,6 +1,8 @@
 # Goomph releases
 
 ## [Unreleased]
+### Added
+- New plugin `com.diffplug.configuration-cache-for-platform-specific-build` which makes the `OS.getNative()` and `SwtPlatform.xxx` methods work without breaking the Gradle configuration cache. ([#153](https://github.com/diffplug/goomph/pull/153))
 
 ## [3.31.0] - 2021-07-23
 ### Added

README.md

@@ -108,6 +108,10 @@ Below is an index of Goomph's capabilities, along with links to the javadoc wher
 
 * Used to power the infrastructure above.
 
+#### Other
+
+* [`com.diffplug.configuration-cache-for-platform-specific-build`](https://javadoc.io/doc/com.diffplug.gradle/goomph/3.31.0/com/diffplug/gradle/swt/PlatformSpecificBuildPlugin.html) allows you to use `OS.getNative()` and `OS.getRunning()` in your gradle build without breaking the configuration cache.
+
 <!---freshmark /javadoc -->
 
 ## Acknowledgements

build.gradle

@@ -24,7 +24,7 @@ spotless {
 }
 
 String VER_DURIAN = '1.2.0'
-String VER_DURIAN_SWT = '3.4.0'
+String VER_DURIAN_SWT = '3.5.0'
 String VER_BNDLIB = '5.3.0'
 String OLDEST_SUPPORTED_GRADLE = '5.1'
 String VER_P2_BOOTSTRAP = '4.13.0'
@@ -42,8 +42,8 @@ dependencies {
 	// OSGi
 	implementation "biz.aQute.bnd:biz.aQute.bndlib:${VER_BNDLIB}"
 	// testing
-	testImplementation "junit:junit:4.13"
-	testImplementation "org.assertj:assertj-core:3.14.0"
+	testImplementation "junit:junit:4.13.2"
+	testImplementation "org.assertj:assertj-core:3.20.2"
 }
 
 configurations.compileClasspath {

gradle.properties

@@ -14,6 +14,7 @@ plugin_list=\
     eclipseResourceFilters \
     equinoxLaunch \
     oomphIde \
+    platformSpecificBuild \
     p2AsMaven \
     osgiBndManifest \
     swtNativeDeps
@@ -63,6 +64,12 @@ plugin_oomphIde_name=Goomph oomphIde
 plugin_oomphIde_desc=Downloads and sets up any Eclipse-based IDE.
 plugin_oomphIde_tags=eclipse ide p2AsMaven
 
+plugin_platformSpecificBuild_id=com.diffplug.configuration-cache-for-platform-specific-build
+plugin_platformSpecificBuild_impl=com.diffplug.gradle.swt.PlatformSpecificBuildPlugin
+plugin_platformSpecificBuild_name=Goomph configuration-cache friendly platform specific build
+plugin_platformSpecificBuild_desc=Allows `OS.getNative()` and `OS.getRunning()` to work with configuration cache
+plugin_platformSpecificBuild_tags=configuration-cache platform-specific
+
 plugin_p2AsMaven_id=com.diffplug.p2.asmaven
 plugin_p2AsMaven_impl=com.diffplug.gradle.p2.AsMavenPlugin
 plugin_p2AsMaven_name=Goomph p2AsMaven

src/main/java/com/diffplug/gradle/swt/PlatformSpecificBuildPlugin.java

@@ -0,0 +1,38 @@
+/*
+ * Copyright (C) 2021 DiffPlug
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.diffplug.gradle.swt;
+
+
+import com.diffplug.common.swt.os.OS;
+import org.gradle.api.Plugin;
+import org.gradle.api.initialization.Settings;
+
+/**
+ * In order to detect the underlying operating system and architecture, it is necessary to
+ * to read various system properties and environment variables, which breaks the Gradle configuration cache.
+ * But, if you apply `com.diffplug.configuration-cache-for-platform-specific-build` in your `settings.gradle`,
+ * then you can call {@link OS#getRunning()} and {@link OS#getNative()} and behind the scenes it will use
+ * <a href="https://docs.gradle.org/current/userguide/configuration_cache.html#config_cache:requirements:undeclared_sys_prop_read">
+ * the appropriate APIs</a> which don't break the configuration cache.
+ */
+public class PlatformSpecificBuildPlugin implements Plugin<Settings> {
+	@Override
+	public void apply(Settings settings) {
+		OS.detectPlatform(
+				systemProp -> settings.getProviders().systemProperty(systemProp).forUseAtConfigurationTime().get(),
+				envVar -> settings.getProviders().environmentVariable(envVar).forUseAtConfigurationTime().get());
+	}
+}

src/test/java/com/diffplug/gradle/swt/PlatformSpecificBuildPluginTest.java

@@ -0,0 +1,66 @@
+/*
+ * Copyright (C) 2021 DiffPlug
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.diffplug.gradle.swt;
+
+
+import com.diffplug.gradle.GradleIntegrationTest;
+import java.io.IOException;
+import org.gradle.testkit.runner.GradleRunner;
+import org.junit.Ignore;
+import org.junit.Test;
+
+public class PlatformSpecificBuildPluginTest extends GradleIntegrationTest {
+	protected GradleRunner gradleRunner() {
+		return super.gradleRunner().withGradleVersion("7.2");
+	}
+
+	private GradleRunner breakConfigCache() throws IOException {
+		write("gradle.properties", "org.gradle.unsafe.configuration-cache=true");
+		write("build.gradle",
+				"plugins {",
+				"  id 'java'",
+				"  id 'com.diffplug.eclipse.mavencentral'",
+				"}",
+				"repositories { mavenCentral() }",
+				"eclipseMavenCentral {",
+				"  release '4.20.0', {",
+				"    implementation 'org.eclipse.swt'",
+				"    implementation 'org.eclipse.jface'",
+				"    implementation \"org.eclipse.swt.${com.diffplug.common.swt.os.SwtPlatform.getRunning()}\"",
+				"    useNativesForRunningPlatform()",
+				"  }",
+				"}");
+		write("src/main/java/pkg/Demo.java",
+				"package pkg;",
+				"public class Demo {}");
+		return gradleRunner().withArguments("jar");
+	}
+
+	@Test
+	@Ignore // fails in real project, but not unit test, not sure why
+	public void configurationCacheBroken() throws IOException {
+		breakConfigCache().buildAndFail();
+	}
+
+	@Test
+	public void configurationCacheWorks() throws IOException {
+		write("settings.gradle",
+				"plugins {",
+				"  id 'com.diffplug.configuration-cache-for-platform-specific-build'",
+				"}");
+		breakConfigCache().build();
+	}
+}