Add @required and @default smithy-diff support

smithy-diff/src/main/java/software/amazon/smithy/diff/evaluators/AddedDefaultTrait.java

@@ -0,0 +1,49 @@
+/*
+ * Copyright 2021 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.diff.evaluators;
+
+import java.util.List;
+import java.util.Objects;
+import java.util.stream.Collectors;
+import software.amazon.smithy.diff.Differences;
+import software.amazon.smithy.model.shapes.MemberShape;
+import software.amazon.smithy.model.traits.DefaultTrait;
+import software.amazon.smithy.model.traits.RequiredTrait;
+import software.amazon.smithy.model.validation.ValidationEvent;
+
+/**
+ * The default trait can only be added to shape if it's replacing the
+ * required trait.
+ */
+public class AddedDefaultTrait extends AbstractDiffEvaluator {
+    @Override
+    public List<ValidationEvent> evaluate(Differences differences) {
+        return differences.changedShapes(MemberShape.class)
+                .map(change -> {
+                    MemberShape oldShape = change.getOldShape();
+                    MemberShape newShape = change.getNewShape();
+                    if (newShape.hasTrait(DefaultTrait.class)
+                            && !oldShape.hasTrait(DefaultTrait.class)
+                            && !oldShape.hasTrait(RequiredTrait.class)) {
+                        return error(newShape, "Added the @default trait. This is only backward compatible if "
+                                               + "the @default trait is used to replace the @required trait.");
+                    }
+                    return null;
+                })
+                .filter(Objects::nonNull)
+                .collect(Collectors.toList());
+    }
+}

smithy-diff/src/main/java/software/amazon/smithy/diff/evaluators/RemovedRequiredTrait.java

@@ -0,0 +1,60 @@
+/*
+ * Copyright 2021 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.diff.evaluators;
+
+import java.util.List;
+import java.util.Objects;
+import java.util.stream.Collectors;
+import software.amazon.smithy.diff.Differences;
+import software.amazon.smithy.model.Model;
+import software.amazon.smithy.model.shapes.MemberShape;
+import software.amazon.smithy.model.traits.DefaultTrait;
+import software.amazon.smithy.model.traits.InputTrait;
+import software.amazon.smithy.model.traits.RequiredTrait;
+import software.amazon.smithy.model.validation.ValidationEvent;
+
+/**
+ * When removing the required trait, it has to be replaced with the default
+ * trait, unless the containing structure is marked with the input trait.
+ */
+public class RemovedRequiredTrait extends AbstractDiffEvaluator {
+    @Override
+    public List<ValidationEvent> evaluate(Differences differences) {
+        return differences.changedShapes(MemberShape.class)
+                .map(change -> {
+                    MemberShape oldShape = change.getOldShape();
+                    MemberShape newShape = change.getNewShape();
+                    if (oldShape.hasTrait(RequiredTrait.class)
+                            && !newShape.hasTrait(RequiredTrait.class)
+                            && !newShape.hasTrait(DefaultTrait.class)
+                            && !containerHasInputTrait(differences.getNewModel(), newShape)) {
+                        return error(newShape, "Removed the @required trait without replacing it with the @default "
+                                               + "trait. Code generated for this structure will change in a backward "
+                                               + "incompatible way in many languages, including Rust, Kotlin, Swift, "
+                                               + "and many others.");
+                    }
+                    return null;
+                })
+                .filter(Objects::nonNull)
+                .collect(Collectors.toList());
+    }
+
+    private boolean containerHasInputTrait(Model model, MemberShape member) {
+        return model.getShape(member.getContainer())
+                .filter(container -> container.hasTrait(InputTrait.class))
+                .isPresent();
+    }
+}

smithy-diff/src/main/resources/META-INF/services/software.amazon.smithy.diff.DiffEvaluator

@@ -1,3 +1,4 @@
+software.amazon.smithy.diff.evaluators.AddedDefaultTrait
 software.amazon.smithy.diff.evaluators.AddedEntityBinding
 software.amazon.smithy.diff.evaluators.AddedMetadata
 software.amazon.smithy.diff.evaluators.AddedOperationError
@@ -19,6 +20,7 @@ software.amazon.smithy.diff.evaluators.RemovedAuthenticationScheme
 software.amazon.smithy.diff.evaluators.RemovedEntityBinding
 software.amazon.smithy.diff.evaluators.RemovedMetadata
 software.amazon.smithy.diff.evaluators.RemovedOperationError
+software.amazon.smithy.diff.evaluators.RemovedRequiredTrait
 software.amazon.smithy.diff.evaluators.RemovedServiceError
 software.amazon.smithy.diff.evaluators.RemovedShape
 software.amazon.smithy.diff.evaluators.RemovedTraitDefinition

smithy-diff/src/test/java/software/amazon/smithy/diff/evaluators/AddedDefaultTraitTest.java

@@ -0,0 +1,75 @@
+/*
+ * Copyright 2021 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.diff.evaluators;
+
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.is;
+
+import org.junit.jupiter.api.Test;
+import software.amazon.smithy.diff.ModelDiff;
+import software.amazon.smithy.model.Model;
+import software.amazon.smithy.model.shapes.StringShape;
+import software.amazon.smithy.model.shapes.StructureShape;
+import software.amazon.smithy.model.traits.DefaultTrait;
+import software.amazon.smithy.model.traits.RequiredTrait;
+import software.amazon.smithy.model.validation.Severity;
+
+public class AddedDefaultTraitTest {
+    @Test
+    public void replacingRequiredTraitWithDefaultIsOk() {
+        StringShape s = StringShape.builder().id("smithy.example#Str").build();
+        StructureShape a = StructureShape.builder()
+                .id("smithy.example#A")
+                .addMember("foo", s.getId(), b1 -> b1.addTrait(new RequiredTrait()))
+                .build();
+        StructureShape b = StructureShape.builder()
+                .id("smithy.example#A")
+                .addMember("foo", s.getId(), b2 -> b2.addTrait(new DefaultTrait()))
+                .build();
+        Model model1 = Model.builder().addShapes(s, a).build();
+        Model model2 = Model.builder().addShapes(s, b).build();
+        ModelDiff.Result result = ModelDiff.builder().oldModel(model1).newModel(model2).compare();
+
+        assertThat(result.getDiffEvents().stream()
+                           .filter(event -> event.getId().equals("AddedDefaultTrait"))
+                           .count(), equalTo(0L));
+    }
+
+    @Test
+    public void detectsInvalidAdditionOfDefaultTrait() {
+        StringShape s = StringShape.builder().id("smithy.example#Str").build();
+        StructureShape a = StructureShape.builder()
+                .id("smithy.example#A")
+                .addMember("foo", s.getId())
+                .build();
+        StructureShape b = StructureShape.builder()
+                .id("smithy.example#A")
+                .addMember("foo", s.getId(), builder -> builder.addTrait(new DefaultTrait()))
+                .build();
+        Model model1 = Model.builder().addShapes(s, a).build();
+        Model model2 = Model.builder().addShapes(s, b).build();
+        ModelDiff.Result result = ModelDiff.builder().oldModel(model1).newModel(model2).compare();
+
+        assertThat(result.isDiffBreaking(), is(true));
+        assertThat(result.getDiffEvents().stream()
+                           .filter(event -> event.getSeverity() == Severity.ERROR)
+                           .filter(event -> event.getId().equals("AddedDefaultTrait"))
+                           .filter(event -> event.getShapeId().get().equals(a.getAllMembers().get("foo").getId()))
+                           .filter(event -> event.getMessage().contains("Added the @default trait"))
+                           .count(), equalTo(1L));
+    }
+}

smithy-diff/src/test/java/software/amazon/smithy/diff/evaluators/RemovedRequiredTraitTest.java

@@ -0,0 +1,98 @@
+/*
+ * Copyright 2021 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.diff.evaluators;
+
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.is;
+
+import org.junit.jupiter.api.Test;
+import software.amazon.smithy.diff.ModelDiff;
+import software.amazon.smithy.model.Model;
+import software.amazon.smithy.model.shapes.StringShape;
+import software.amazon.smithy.model.shapes.StructureShape;
+import software.amazon.smithy.model.traits.DefaultTrait;
+import software.amazon.smithy.model.traits.InputTrait;
+import software.amazon.smithy.model.traits.RequiredTrait;
+import software.amazon.smithy.model.validation.Severity;
+
+public class RemovedRequiredTraitTest {
+    @Test
+    public void replacingRequiredTraitWithDefaultIsOk() {
+        StringShape s = StringShape.builder().id("smithy.example#Str").build();
+        StructureShape a = StructureShape.builder()
+                .id("smithy.example#A")
+                .addMember("foo", s.getId(), b1 -> b1.addTrait(new RequiredTrait()))
+                .build();
+        StructureShape b = StructureShape.builder()
+                .id("smithy.example#A")
+                .addMember("foo", s.getId(), b2 -> b2.addTrait(new DefaultTrait()))
+                .build();
+        Model model1 = Model.builder().addShapes(s, a).build();
+        Model model2 = Model.builder().addShapes(s, b).build();
+        ModelDiff.Result result = ModelDiff.builder().oldModel(model1).newModel(model2).compare();
+
+        assertThat(result.getDiffEvents().stream()
+                           .filter(event -> event.getId().equals("RemovedRequiredTrait"))
+                           .count(), equalTo(0L));
+    }
+
+    @Test
+    public void removingTheRequiredTraitOnInputStructureIsOk() {
+        StringShape s = StringShape.builder().id("smithy.example#Str").build();
+        StructureShape a = StructureShape.builder()
+                .addTrait(new InputTrait())
+                .id("smithy.example#A")
+                .addMember("foo", s.getId(), b1 -> b1.addTrait(new RequiredTrait()))
+                .build();
+        StructureShape b = StructureShape.builder()
+                .addTrait(new InputTrait())
+                .id("smithy.example#A")
+                .addMember("foo", s.getId())
+                .build();
+        Model model1 = Model.builder().addShapes(s, a).build();
+        Model model2 = Model.builder().addShapes(s, b).build();
+        ModelDiff.Result result = ModelDiff.builder().oldModel(model1).newModel(model2).compare();
+
+        assertThat(result.getDiffEvents().stream()
+                           .filter(event -> event.getId().equals("RemovedRequiredTrait"))
+                           .count(), equalTo(0L));
+    }
+
+    @Test
+    public void detectsInvalidRemovalOfRequired() {
+        StringShape s = StringShape.builder().id("smithy.example#Str").build();
+        StructureShape a = StructureShape.builder()
+                .id("smithy.example#A")
+                .addMember("foo", s.getId(), b1 -> b1.addTrait(new RequiredTrait()))
+                .build();
+        StructureShape b = StructureShape.builder()
+                .id("smithy.example#A")
+                .addMember("foo", s.getId())
+                .build();
+        Model model1 = Model.builder().addShapes(s, a).build();
+        Model model2 = Model.builder().addShapes(s, b).build();
+        ModelDiff.Result result = ModelDiff.builder().oldModel(model1).newModel(model2).compare();
+
+        assertThat(result.isDiffBreaking(), is(true));
+        assertThat(result.getDiffEvents().stream()
+                           .filter(event -> event.getSeverity() == Severity.ERROR)
+                           .filter(event -> event.getId().equals("RemovedRequiredTrait"))
+                           .filter(event -> event.getShapeId().get().equals(a.getAllMembers().get("foo").getId()))
+                           .filter(event -> event.getMessage().contains("Removed the @required trait"))
+                           .count(), equalTo(1L));
+    }
+}