enable error rename by protocols

docs/source-1.0/spec/aws/aws-json-1_1-protocol.rst

@@ -137,4 +137,28 @@ The following example defines a service that requires the use of
 .. |protocol test link| replace:: https://github.com/awslabs/smithy/tree/main/smithy-aws-protocol-tests/model/awsJson1_1
 .. include:: aws-json.rst.template
 
+
+--------------------
+Error shape renaming
+--------------------
+
+By default, Smithy permits renaming shapes to disambiguate shape ID conflicts in
+the :ref:`service closure <service-closure>` via the ``rename`` property.
+
+However, services using the ``awsJson1_1`` protocol are not
+allowed to rename error shapes (shapes with :ref:`error trait <error-trait>` applied).
+
+Client-side implementation relies on the response body field ``code`` or ``__type`` to resolve the error type.
+Server-side implementation of ``awsJson1_1`` protocol will only send the ``shape name`` for the response body field.
+
+When there are conflicting shape IDs ``smithy.service#ServiceError`` and ``smithy.other#ServiceError``,
+server-side will only send shape name ``ServiceError``. Client-side implementation will not be able to resolve
+the correct error type without the ``namespace``.
+
+Server-side implementation of ``awsJson1_1`` protocol doesn't handle or send renamed shape names.
+As a result, renaming will not resolve the conflicting shape IDs issue, and hence it is not permitted.
+
+The resolution should be to avoid having conflicting error shape IDs.
+
+
 .. _`Application-Layer Protocol Negotiation (ALPN) Protocol ID`: https://www.iana.org/assignments/tls-extensiontype-values/tls-extensiontype-values.xhtml#alpn-protocol-ids

docs/source-1.0/spec/core/model.rst

@@ -1141,9 +1141,9 @@ The service shape supports the following properties:
           shape name or the name of a non-renamed shape contained in the
           service.
         * Member shapes MAY NOT be renamed.
-        * Resource, operation, and shapes marked with the :ref:`error-trait`
-          MAY NOT be renamed. Renaming shapes is intended for incidental naming
-          conflicts, not for renaming the fundamental concepts of a service.
+        * Resource and operation shapes MAY NOT be renamed. Renaming shapes is intended
+          for incidental naming conflicts, not for renaming the fundamental concepts
+          of a service.
         * Shapes from other namespaces marked as :ref:`private <private-trait>`
           MAY be renamed.
         * A rename MUST use a name that is case-sensitively different from the

docs/source-2.0/aws/protocols/aws-json-1_1-protocol.rst

@@ -128,4 +128,28 @@ The following example defines a service that requires the use of
 .. |protocol test link| replace:: https://github.com/awslabs/smithy/tree/main/smithy-aws-protocol-tests/model/awsJson1_1
 .. include:: aws-json.rst.template
 
+
+--------------------
+Error shape renaming
+--------------------
+
+By default, Smithy permits renaming shapes to disambiguate shape ID conflicts in
+the :ref:`service closure <service-closure>` via the ``rename`` property.
+
+However, services using the ``awsJson1_1`` protocol are not
+allowed to rename error shapes (shapes with :ref:`error trait <error-trait>` applied).
+
+According to ``Operation error serialization``,
+client-side implementation relies on the response body field ``code`` or ``__type`` to resolve the error type.
+Server-side implementation of ``awsJson1_1`` protocol will only send the ``shape name`` for the response body field.
+
+When there are conflicting shape IDs ``smithy.service#ServiceError`` and ``smithy.other#ServiceError``,
+server-side will only send the shape name ``ServiceError``. Client-side implementation will not be able to resolve
+the correct error type without the ``namespace``.
+
+Server-side implementation of ``awsJson1_1`` protocol doesn't handle or send renamed shape names.
+As a result, renaming will not resolve the conflicting shape IDs issue, and hence it is not permitted.
+
+The resolution should be to avoid having conflicting error shape IDs.
+
 .. _`Application-Layer Protocol Negotiation (ALPN) Protocol ID`: https://www.iana.org/assignments/tls-extensiontype-values/tls-extensiontype-values.xhtml#alpn-protocol-ids

docs/source-2.0/spec/service-types.rst

@@ -62,9 +62,9 @@ The service shape supports the following properties:
           shape name or the name of a non-renamed shape contained in the
           service.
         * Member shapes MAY NOT be renamed.
-        * Resource, operation, and shapes marked with the :ref:`error-trait`
-          MAY NOT be renamed. Renaming shapes is intended for incidental naming
-          conflicts, not for renaming the fundamental concepts of a service.
+        * Resource and operation shapes MAY NOT be renamed. Renaming shapes is intended
+          for incidental naming conflicts, not for renaming the fundamental concepts
+          of a service.
         * Shapes from other namespaces marked as :ref:`private <private-trait>`
           MAY be renamed.
         * A rename MUST use a name that is case-sensitively different from the

smithy-aws-traits/src/main/java/software/amazon/smithy/aws/traits/ErrorRenameValidator.java

@@ -0,0 +1,96 @@
+/*
+ * Copyright 2022 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License").
+ * You may not use this file except in compliance with the License.
+ * A copy of the License is located at
+ *
+ *  http://aws.amazon.com/apache2.0
+ *
+ * or in the "license" file accompanying this file. This file 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 software.amazon.smithy.aws.traits;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+import java.util.Set;
+import java.util.stream.Collectors;
+import software.amazon.smithy.aws.traits.protocols.AwsJson1_1Trait;
+import software.amazon.smithy.aws.traits.protocols.AwsProtocolTrait;
+import software.amazon.smithy.model.Model;
+import software.amazon.smithy.model.shapes.ServiceShape;
+import software.amazon.smithy.model.shapes.ShapeId;
+import software.amazon.smithy.model.traits.ErrorTrait;
+import software.amazon.smithy.model.validation.AbstractValidator;
+import software.amazon.smithy.model.validation.ValidationEvent;
+import software.amazon.smithy.utils.SetUtils;
+import software.amazon.smithy.utils.SmithyInternalApi;
+
+@SmithyInternalApi
+public final class ErrorRenameValidator extends AbstractValidator {
+
+    /**
+     * By default, server-side implementation of AWS Protocols send the error shape ID on the wire,
+     * and clients can use it to resolve the error type.
+     *
+     * However, some protocols implementations, including AWS JSON 1.1, only send the shape name.
+     * If there are conflicting shape IDs e.g. smithy.service#ServiceError and smithy.other#ServiceError,
+     * clients are unable to resolve the error type with the shape name alone.
+     *
+     * In addition, Server-side implementation of these protocols don't handle or send renamed shape names.
+     *
+     * Hence, error shape renaming are not supported for these protocols.
+     */
+    private static final Set<Class<? extends AwsProtocolTrait>> UNSUPPORTED_PROTOCOLS =
+        SetUtils.of(AwsJson1_1Trait.class);
+
+    @Override
+    public List<ValidationEvent> validate(Model model) {
+        List<ValidationEvent> events = new ArrayList<>();
+        for (ServiceShape shape : model.getServiceShapes()) {
+            validate(model, shape, events);
+        }
+        return events;
+    }
+
+    private void validate(Model model, ServiceShape service, List<ValidationEvent> events) {
+        final Map<ShapeId, String> renames = service.getRename();
+
+        if (renames.isEmpty()) {
+            return;
+        }
+
+        Set<String> unSupportedProtocols = getUnsupportedProtocols(service);
+
+        if (unSupportedProtocols.isEmpty()) {
+            return;
+        }
+
+        renames.keySet().stream()
+            .map(model::getShape)
+            .filter(Optional::isPresent)
+            .map(Optional::get)
+            .filter(shape -> shape.hasTrait(ErrorTrait.class))
+            .forEach(shape -> {
+                ShapeId from = shape.getId();
+                String to = renames.get(from);
+                events.add(error(service, String.format(
+                        "Service attempts to rename an error shape from `%s` to \"%s\"; "
+                                + "Service protocols %s do not support error renaming.",
+                        from, to, unSupportedProtocols)));
+            });
+    }
+
+    private Set<String> getUnsupportedProtocols(ServiceShape service) {
+        return service.getAllTraits().values().stream()
+            .filter(trait -> UNSUPPORTED_PROTOCOLS.contains(trait.getClass()))
+            .map(trait -> trait.toShapeId().getName())
+            .collect(Collectors.toSet());
+    }
+}

smithy-aws-traits/src/main/resources/META-INF/services/software.amazon.smithy.model.validation.Validator

@@ -10,3 +10,4 @@ software.amazon.smithy.aws.traits.tagging.TagEnabledServiceValidator
 software.amazon.smithy.aws.traits.tagging.TaggableResourceValidator
 software.amazon.smithy.aws.traits.tagging.TagResourcePropertyTypeValidator
 software.amazon.smithy.aws.traits.tagging.TagResourcePropertyNameValidator
+software.amazon.smithy.aws.traits.ErrorRenameValidator

smithy-aws-traits/src/test/resources/software/amazon/smithy/aws/traits/errorfiles/error-rename.errors

@@ -0,0 +1,2 @@
+[ERROR] smithy.example#MyService: Service attempts to rename an error shape from `smithy.example#BadGreeting` to "ThisDoesNotWork"; Service protocols [awsJson1_1] do not support error renaming. | ErrorRename
+[ERROR] smithy.example#MyService: Service attempts to rename an error shape from `smithy.example#ServerError` to "ServerDown"; Service protocols [awsJson1_1] do not support error renaming. | ErrorRename

smithy-aws-traits/src/test/resources/software/amazon/smithy/aws/traits/errorfiles/error-rename.smithy

@@ -0,0 +1,42 @@
+$version: "2.0"
+
+namespace smithy.example
+
+use aws.protocols#awsJson1_1
+use aws.protocols#restXml
+
+@awsJson1_1
+@restXml
+service MyService {
+    version: "1",
+    operations: [
+        SayHello,
+    ],
+    rename: {
+        "smithy.example#BadGreeting": "ThisDoesNotWork"
+        "smithy.example#ServerError": "ServerDown"
+        "smithy.example#Language": "LanguageSettings"
+    }
+}
+
+operation SayHello {
+    input: SayHelloInput,
+    output: SayHelloOutput,
+    errors: [BadGreeting, ServerError]
+}
+
+@input
+structure SayHelloInput {
+    language: Language
+}
+
+@output
+structure SayHelloOutput {}
+
+@error("client")
+structure BadGreeting {}
+
+@error("server")
+structure ServerError {}
+
+structure Language {}

smithy-model/src/main/java/software/amazon/smithy/model/validation/validators/ServiceValidator.java

@@ -35,7 +35,6 @@
 import software.amazon.smithy.model.shapes.Shape;
 import software.amazon.smithy.model.shapes.ShapeId;
 import software.amazon.smithy.model.shapes.SimpleShape;
-import software.amazon.smithy.model.traits.ErrorTrait;
 import software.amazon.smithy.model.traits.Trait;
 import software.amazon.smithy.model.validation.AbstractValidator;
 import software.amazon.smithy.model.validation.Severity;
@@ -156,8 +155,6 @@ private List<ValidationEvent> validateRenames(ServiceShape service, Map<ShapeId,
     private Optional<String> getInvalidRenameReason(Shape shape) {
         if (shape.isMemberShape() || shape.isResourceShape() || shape.isOperationShape()) {
             return Optional.of(shape.getType() + "s cannot be renamed");
-        } else if (shape.hasTrait(ErrorTrait.class)) {
-            return Optional.of("errors cannot be renamed");
         } else {
             return Optional.empty();
         }

smithy-model/src/test/resources/software/amazon/smithy/model/errorfiles/validators/service-rename/error-rename-invalid.errors

@@ -1 +0,0 @@
-[ERROR] smithy.example#MyService: Service attempts to rename a structure shape from `smithy.example#BadGreeting` to "ThisDoesNotWork"; errors cannot be renamed | Service