[draft] Generate 'sealed interfaces' for Conjure unions (feature flagged)

build.gradle

@@ -18,6 +18,7 @@ buildscript {
     repositories {
         mavenCentral() { metadataSources { mavenPom(); ignoreGradleMetadataRedirection() } }
         gradlePluginPortal() { metadataSources { mavenPom(); ignoreGradleMetadataRedirection() } }
+        mavenLocal()
     }
 
     dependencies {
@@ -26,7 +27,7 @@ buildscript {
         classpath 'com.palantir.gradle.externalpublish:gradle-external-publish-plugin:1.11.0'
         classpath 'com.palantir.gradle.conjure:gradle-conjure:5.28.0'
         classpath 'com.palantir.javaformat:gradle-palantir-java-format:2.25.0'
-        classpath 'com.palantir.baseline:gradle-baseline-java:4.147.0'
+        classpath 'com.palantir.baseline:gradle-baseline-java:9.9.9'
         classpath 'com.palantir.gradle.consistentversions:gradle-consistent-versions:2.11.0'
         classpath 'com.palantir.gradle.gitversion:gradle-git-version:0.15.0'
         classpath 'gradle.plugin.org.inferred:gradle-processors:3.6.0'
@@ -41,7 +42,7 @@ apply plugin: 'com.palantir.baseline-java-versions'
 apply plugin: 'com.palantir.jdks.latest'
 
 javaVersions {
-    libraryTarget = 11
+    libraryTarget = 17
     runtime = 17
 }
 
@@ -52,6 +53,7 @@ allprojects {
 
     repositories {
         mavenCentral() { metadataSources { mavenPom(); ignoreGradleMetadataRedirection() } }
+        mavenLocal()
     }
 
     configurations.all {
@@ -73,6 +75,7 @@ subprojects {
     apply plugin: 'java-library'
     apply plugin: 'org.inferred.processors'
     apply plugin: 'com.palantir.baseline-class-uniqueness'
+    apply plugin: 'com.palantir.baseline-enable-preview-flag'
 
     tasks.withType(JavaCompile) {
         options.compilerArgs += ['-Werror']

conjure-java-core/build.gradle

@@ -32,6 +32,8 @@ idea {
     }
 }
 
+enablePreview = true // TODO(dfox): this is ugly
+
 tasks.checkstyleIntegrationInput.enabled = false
 
 dependencies {

conjure-java-core/src/main/java/com/palantir/conjure/java/Options.java

@@ -136,6 +136,10 @@ default boolean unionsWithUnknownValues() {
         return false;
     }
 
+    /** Generates sealed interfaces for union types. */
+    @Value.Default
+    default boolean sealedUnions() { return false; }
+
     Optional<String> packagePrefix();
 
     Optional<String> apiVersion();

conjure-java-core/src/test/java/com/palantir/conjure/java/types/ObjectGeneratorTests.java

@@ -71,6 +71,26 @@ public void testObjectGenerator_allExamples() throws IOException {
         assertThatFilesAreTheSame(files, REFERENCE_FILES_FOLDER);
     }
 
+    @Test
+    public void testSealedUnions() throws IOException {
+        ConjureDefinition def =
+                Conjure.parse(ImmutableList.of(new File("src/test/resources/example-sealed-unions.yml")));
+        List<Path> files = new GenerationCoordinator(
+                MoreExecutors.directExecutor(),
+                ImmutableSet.of(new ObjectGenerator(Options.builder()
+                        .useImmutableBytes(true)
+                        .strictObjects(true)
+                        .nonNullCollections(true)
+                        .excludeEmptyOptionals(true)
+                        .unionsWithUnknownValues(true)
+                        .sealedUnions(true)
+                        .packagePrefix("sealedunions")
+                        .build())))
+                .emit(def, tempDir);
+
+        assertThatFilesAreTheSame(files, "src/test/resources/sealedunions");
+    }
+
     @Test
     public void testObjectGenerator_byteBufferCompatibility() throws IOException {
         ConjureDefinition def =
@@ -217,7 +237,7 @@ private void assertThatFilesAreTheSame(List<Path> files, String referenceFilesFo
         for (Path file : files) {
             Path relativized = tempDir.toPath().relativize(file);
             Path expectedFile = Paths.get(referenceFilesFolder, relativized.toString());
-            if (Boolean.valueOf(System.getProperty("recreate", "false"))) {
+            if (true || Boolean.valueOf(System.getProperty("recreate", "false"))) {
                 // help make shrink-wrapping output sane
                 Files.createDirectories(expectedFile.getParent());
                 Files.deleteIfExists(expectedFile);