Update codegen to support closure-based generation

codegen/codegen-core/src/internal/java/software/amazon/smithy/java/codegen/JavaTypesCodegenPlugin.java

@@ -5,17 +5,14 @@
 
 package software.amazon.smithy.java.codegen;
 
-import java.util.HashSet;
 import java.util.Set;
+import java.util.StringJoiner;
 import software.amazon.smithy.build.PluginContext;
 import software.amazon.smithy.build.SmithyBuildPlugin;
-import software.amazon.smithy.codegen.core.CodegenException;
 import software.amazon.smithy.codegen.core.directed.CodegenDirector;
 import software.amazon.smithy.java.codegen.writer.JavaWriter;
 import software.amazon.smithy.java.logging.InternalLogger;
-import software.amazon.smithy.model.Model;
-import software.amazon.smithy.model.loader.Prelude;
-import software.amazon.smithy.model.shapes.Shape;
+import software.amazon.smithy.model.metadata.ShapeClosure;
 import software.amazon.smithy.utils.SmithyInternalApi;
 
 /**
@@ -42,6 +39,10 @@
 public final class JavaTypesCodegenPlugin implements SmithyBuildPlugin {
     private static final InternalLogger LOGGER = InternalLogger.getLogger(JavaTypesCodegenPlugin.class);
 
+    // Id of the shape closure that drives types-only generation. Namespaced so it cannot collide
+    // with a model shape id or a model-authored closure.
+    private static final String CLOSURE_ID = "software.amazon.smithy.java.codegen#types";
+
     @Override
     public String getName() {
         return "internal-types-only";
@@ -60,35 +61,40 @@ public void execute(PluginContext context) {
         runner.settings(codegenSettings);
         runner.directedCodegen(new TypesDirectedJavaCodegen(modes));
         runner.fileManifest(context.getFileManifest());
-        runner.service(codegenSettings.service());
 
-        // Compute closure and create synthetic service
-        var closure = getClosure(context.getModel(), settings);
-        LOGGER.info("Found {} shapes in generation closure", closure.size());
-        var model = SyntheticServiceTransform.transform(context.getModel(), closure, settings.renames());
-        runner.model(model);
+        // Generate the data shapes selected by the settings as a shape closure, with no
+        // primary service. The director resolves the closure's transitive data shapes.
+        runner.shapeClosure(typesClosure(settings));
+        runner.generateDataShapesOnly();
+        runner.model(context.getModel());
         runner.integrationClass(JavaCodegenIntegration.class);
         DefaultTransforms.apply(runner, codegenSettings);
         runner.run();
         LOGGER.info("Successfully generated Java class files.");
     }
 
-    private static Set<Shape> getClosure(Model model, TypeCodegenSettings settings) {
-        Set<Shape> closure = new HashSet<>();
-        for (var shapeId : settings.shapes()) {
-            closure.add(model.expectShape(shapeId));
-        }
-        settings.selector()
-                .shapes(model)
-                .filter(s -> !s.isMemberShape())
-                .filter(s -> !Prelude.isPreludeShape(s))
-                .forEach(closure::add);
-
-        if (closure.isEmpty()) {
-            throw new CodegenException("Could not generate types. No shapes found in closure");
+    /**
+     * Builds the shape closure to generate from the configured selector, explicitly listed shapes,
+     * and renames. Explicit shapes are folded into the selector as id-equality clauses and trait
+     * definitions are excluded so only data shapes are generated.
+     */
+    private static ShapeClosure typesClosure(TypeCodegenSettings settings) {
+        // Fold the explicit shapes into the configured selector as id-equality alternatives,
+        // e.g. :is(<selector>, [id='ns#A'], [id='ns#B']).
+        String base = settings.selector().toString();
+        if (!settings.shapes().isEmpty()) {
+            var joiner = new StringJoiner(", ", ":is(", ")");
+            joiner.add(base);
+            for (var shape : settings.shapes()) {
+                joiner.add("[id='" + shape + "']");
+            }
+            base = joiner.toString();
         }
-        LOGGER.info("Found {} shapes in generation closure.", closure.size());
-
-        return closure;
+        return ShapeClosure.builder()
+                .id(CLOSURE_ID)
+                // Exclude trait definitions so only data shapes are generated.
+                .includeBySelector(base + " :not([trait|trait])")
+                .rename(settings.renames())
+                .build();
     }
 }

codegen/codegen-core/src/internal/java/software/amazon/smithy/java/codegen/TypesDirectedJavaCodegen.java

@@ -30,7 +30,6 @@
 import software.amazon.smithy.java.codegen.generators.SharedSerdeGenerator;
 import software.amazon.smithy.java.codegen.generators.StructureGenerator;
 import software.amazon.smithy.java.codegen.generators.UnionGenerator;
-import software.amazon.smithy.model.shapes.Shape;
 import software.amazon.smithy.utils.SmithyInternalApi;
 
 /**
@@ -53,7 +52,8 @@ public SymbolProvider createSymbolProvider(
     ) {
         return new JavaSymbolProvider(
                 directive.model(),
-                directive.service(),
+                directive.getService().orElse(null),
+                directive.getRenames(),
                 directive.settings().packageNamespace(),
                 directive.settings().name(),
                 modes);
@@ -68,9 +68,7 @@ public CodeGenerationContext createContext(
 
     @Override
     public void generateStructure(GenerateStructureDirective<CodeGenerationContext, JavaCodegenSettings> directive) {
-        if (!isSynthetic(directive.shape())) {
-            new StructureGenerator<>().accept(directive);
-        }
+        new StructureGenerator<>().accept(directive);
     }
 
     @Override
@@ -129,8 +127,4 @@ public void customizeBeforeIntegrations(CustomizeDirective<CodeGenerationContext
     public void customizeAfterIntegrations(CustomizeDirective<CodeGenerationContext, JavaCodegenSettings> directive) {
         // No-op for types-only mode
     }
-
-    private static boolean isSynthetic(Shape shape) {
-        return shape.getId().getNamespace().equals(SyntheticServiceTransform.SYNTHETIC_NAMESPACE);
-    }
 }

codegen/codegen-core/src/main/java/software/amazon/smithy/java/codegen/CodeGenerationContext.java

@@ -14,7 +14,6 @@
 import java.util.stream.Collectors;
 import software.amazon.smithy.build.FileManifest;
 import software.amazon.smithy.codegen.core.CodegenContext;
-import software.amazon.smithy.codegen.core.CodegenException;
 import software.amazon.smithy.codegen.core.SymbolProvider;
 import software.amazon.smithy.codegen.core.WriterDelegator;
 import software.amazon.smithy.codegen.core.directed.CreateContextDirective;
@@ -123,7 +122,7 @@ public CodeGenerationContext(
                 fileManifest,
                 this.symbolProvider,
                 new JavaWriter.Factory(settings));
-        this.runtimeTraits = collectRuntimeTraits();
+        this.runtimeTraits = collectRuntimeTraits(directive.getService().orElse(null));
         this.traitInitializers = collectTraitInitializers();
         this.plugin = plugin;
         this.schemaFieldOrder = new SchemaFieldOrder(directive, this);
@@ -186,32 +185,30 @@ public SchemaFieldOrder schemaFieldOrder() {
      *
      * @return Set of trait ShapeId's to include in generated Schemas.
      */
-    private Set<ShapeId> collectRuntimeTraits() {
-        ServiceShape shape = model.expectShape(settings.service())
-                .asServiceShape()
-                .orElseThrow(
-                        () -> new CodegenException(
-                                "Expected shapeId: "
-                                        + settings.service() + " to be a service shape."));
-
+    private Set<ShapeId> collectRuntimeTraits(ServiceShape service) {
         // Add all default runtime traits from the prelude
         Set<ShapeId> traits = new HashSet<>(PRELUDE_RUNTIME_TRAITS);
-        for (var entry : shape.getAllTraits().entrySet()) {
-            Optional<Shape> traitShapeOptional = model.getShape(entry.getKey());
-            if (traitShapeOptional.isEmpty()) {
-                LOGGER.debug("Skipping unknown trait: {}", entry.getKey());
-                continue;
-            }
-            var traitShape = traitShapeOptional.get();
-            // Add all traits supported by a protocol the service supports
-            if (traitShape.hasTrait(ProtocolDefinitionTrait.class)) {
-                var protocolDef = traitShape.expectTrait(ProtocolDefinitionTrait.class);
-                traits.addAll(protocolDef.getTraits());
-            }
-            // Add all traits supported by auth schemes the service supports
-            if (traitShape.hasTrait(AuthDefinitionTrait.class)) {
-                var authDef = traitShape.expectTrait(AuthDefinitionTrait.class);
-                traits.addAll(authDef.getTraits());
+
+        // Protocol- and auth-scheme-supported traits are rooted in the primary service. Pure types
+        // mode has no service, so only the prelude and customer-configured traits apply.
+        if (service != null) {
+            for (var entry : service.getAllTraits().entrySet()) {
+                Optional<Shape> traitShapeOptional = model.getShape(entry.getKey());
+                if (traitShapeOptional.isEmpty()) {
+                    LOGGER.debug("Skipping unknown trait: {}", entry.getKey());
+                    continue;
+                }
+                var traitShape = traitShapeOptional.get();
+                // Add all traits supported by a protocol the service supports
+                if (traitShape.hasTrait(ProtocolDefinitionTrait.class)) {
+                    var protocolDef = traitShape.expectTrait(ProtocolDefinitionTrait.class);
+                    traits.addAll(protocolDef.getTraits());
+                }
+                // Add all traits supported by auth schemes the service supports
+                if (traitShape.hasTrait(AuthDefinitionTrait.class)) {
+                    var authDef = traitShape.expectTrait(AuthDefinitionTrait.class);
+                    traits.addAll(authDef.getTraits());
+                }
             }
         }
 

codegen/codegen-core/src/main/java/software/amazon/smithy/java/codegen/CodegenUtils.java

@@ -9,6 +9,7 @@
 import java.net.URL;
 import java.util.List;
 import java.util.Locale;
+import java.util.Map;
 import java.util.Objects;
 import java.util.regex.Pattern;
 import java.util.stream.Collectors;
@@ -111,10 +112,24 @@ public static Symbol fromBoxedClass(Class<?> unboxed, Class<?> boxed) {
      * Gets the default class name to use for a given Smithy {@link Shape}.
      *
      * @param shape Shape to get name for.
+     * @param service Service whose renames provide contextual names, or null if none.
      * @return Default name.
      */
     public static String getDefaultName(Shape shape, ServiceShape service) {
-        String baseName = shape.getId().getName(service);
+        return getDefaultName(shape, service == null ? Map.of() : service.getRename());
+    }
+
+    /**
+     * Gets the default class name to use for a given Smithy {@link Shape}.
+     *
+     * @param shape Shape to get name for.
+     * @param renames Renames applied to the generated shapes (a shape id maps to its
+     *     contextual name). Used instead of a service so the closure-driven types path
+     *     can apply renames without a service.
+     * @return Default name.
+     */
+    public static String getDefaultName(Shape shape, Map<ShapeId, String> renames) {
+        String baseName = renames.getOrDefault(shape.getId(), shape.getId().getName());
 
         // If the name contains any problematic delimiters, use PascalCase converter,
         // otherwise, just capitalize first letter to avoid messing with user-defined
@@ -423,7 +438,7 @@ public static boolean isISO8601Date(String string) {
      * @return the property if found, or null.
      */
     public static <T> T tryGetServiceProperty(ShapeDirective<?, ?, ?> directive, Property<T> prop) {
-        var service = directive.service();
+        var service = directive.getService().orElse(null);
         if (service != null) {
             var symbol = directive.symbolProvider().toSymbol(service);
             if (symbol != null) {

codegen/codegen-core/src/main/java/software/amazon/smithy/java/codegen/JavaCodegenSettings.java

@@ -14,6 +14,7 @@
 import java.util.Locale;
 import java.util.Map;
 import java.util.Objects;
+import java.util.Optional;
 import java.util.Set;
 import software.amazon.smithy.codegen.core.CodegenException;
 import software.amazon.smithy.codegen.core.Symbol;
@@ -50,6 +51,13 @@ public final class JavaCodegenSettings {
     private static final String RUNTIME_TRAITS = "runtimeTraits";
     private static final String RUNTIME_TRAITS_SELECTOR = "runtimeTraitsSelector";
     private static final String MODES = "modes";
+    private static final String CLOSURE = "closure";
+
+    // Legacy default name for types-only generation. Before types generation was driven by a shape
+    // closure, it relied on a synthetic service named "TypesGenService", so the generated name
+    // defaulted to that when none was configured. The name is unused by types-only output, but this
+    // value is preserved so existing configs without a 'name' keep behaving as they did.
+    private static final String LEGACY_TYPES_NAME = "TypesGenService";
     private static final List<String> PROPERTIES = List.of(
             SERVICE,
             NAME,
@@ -66,9 +74,11 @@ public final class JavaCodegenSettings {
             EDITION,
             RUNTIME_TRAITS,
             RUNTIME_TRAITS_SELECTOR,
-            MODES);
+            MODES,
+            CLOSURE);
 
     private final ShapeId service;
+    private final String closure;
     private final String name;
     private final String packageNamespace;
     private final String header;
@@ -87,8 +97,9 @@ public final class JavaCodegenSettings {
     private final Map<String, Set<Symbol>> generatedSymbols = new HashMap<>();
 
     private JavaCodegenSettings(Builder builder) {
-        this.service = Objects.requireNonNull(builder.service);
-        this.name = StringUtils.capitalize(Objects.requireNonNullElse(builder.name, service.getName()));
+        this.service = builder.service;
+        this.closure = builder.closure;
+        this.name = StringUtils.capitalize(resolveName(builder.name, service));
         this.packageNamespace = Objects.requireNonNull(builder.packageNamespace);
         this.header = getHeader(builder.headerFilePath, builder.sourceLocation);
         this.addNullnessAnnotations = builder.addNullnessAnnotations;
@@ -105,6 +116,20 @@ private JavaCodegenSettings(Builder builder) {
         this.httpConfig = builder.httpConfig;
     }
 
+    // Resolves the generated name: an explicit name wins, otherwise the service name when a service
+    // is set, otherwise the legacy types-only default (with a warning nudging callers to set one).
+    private static String resolveName(String configuredName, ShapeId service) {
+        if (configuredName != null) {
+            return configuredName;
+        }
+        if (service != null) {
+            return service.getName();
+        }
+        LOGGER.warn("No 'name' configured for types-only generation; defaulting to '{}'. Set the "
+                + "'name' setting explicitly to silence this warning.", LEGACY_TYPES_NAME);
+        return LEGACY_TYPES_NAME;
+    }
+
     /**
      * Creates a settings object from a plugin settings node
      *
@@ -114,7 +139,8 @@ private JavaCodegenSettings(Builder builder) {
     public static JavaCodegenSettings fromNode(ObjectNode settingsNode) {
         var builder = new Builder();
         settingsNode.warnIfAdditionalProperties(PROPERTIES)
-                .expectStringMember(SERVICE, builder::service)
+                .getStringMember(SERVICE, builder::service)
+                .getStringMember(CLOSURE, builder::closure)
                 .getStringMember(NAME, builder::name)
                 .expectStringMember(NAMESPACE, builder::packageNamespace)
                 .getStringMember(HEADER_FILE, builder::headerFilePath)
@@ -135,10 +161,45 @@ public static JavaCodegenSettings fromNode(ObjectNode settingsNode) {
         return builder.build();
     }
 
+    /**
+     * Gets the primary service to generate.
+     *
+     * @return the configured service id.
+     * @see #getService() for a non-throwing variant.
+     */
     public ShapeId service() {
+        if (service == null) {
+            throw new CodegenException(
+                    "No service is configured for this code generation because types-only generation "
+                            + "has no primary service.");
+        }
         return service;
     }
 
+    /**
+     * Gets the primary service to generate, if one is configured.
+     *
+     * <p>Types-only generation is driven by a shape closure and has no primary service, so this
+     * returns an empty optional in that case.
+     *
+     * @return the configured service id, or empty if none is set.
+     */
+    public Optional<ShapeId> getService() {
+        return Optional.ofNullable(service);
+    }
+
+    /**
+     * Gets the id of a pre-authored shape closure to generate, if one was configured.
+     *
+     * <p>When set, generation is driven by the {@code shapeClosures} metadata entry with this id in
+     * the model, rather than by an inline {@code selector}/{@code shapes} configuration.
+     *
+     * @return the configured shape closure id, or empty if none is set.
+     */
+    public Optional<String> getClosure() {
+        return Optional.ofNullable(closure);
+    }
+
     public String name() {
         return name;
     }
@@ -232,6 +293,7 @@ public static Builder builder() {
 
     public static final class Builder {
         private ShapeId service;
+        private String closure;
         private String name;
         private String packageNamespace;
         private String headerFilePath;
@@ -254,6 +316,11 @@ public Builder service(String string) {
             return this;
         }
 
+        public Builder closure(String closure) {
+            this.closure = closure;
+            return this;
+        }
+
         public Builder name(String name) {
             this.name = name;
             return this;