Add validation events decorators

smithy-cli/src/main/java/software/amazon/smithy/cli/ColorTheme.java

@@ -47,5 +47,7 @@ public final class ColorTheme {
     public static final Style DIFF_TITLE = Style.of(Style.BG_BRIGHT_BLACK, Style.WHITE);
     public static final Style DIFF_EVENT_TITLE = Style.of(Style.BG_BRIGHT_BLUE, Style.BLACK);
 
+    public static final Style HINT_TITLE = Style.of(Style.BRIGHT_GREEN);
+
     private ColorTheme() {}
 }

smithy-cli/src/main/java/software/amazon/smithy/cli/commands/PrettyAnsiValidationFormatter.java

@@ -104,6 +104,13 @@ public String format(ValidationEvent event) {
 
             writeMessage(writer, event.getMessage());
             writer.append(ls);
+            event.getHint().ifPresent(hint -> {
+                String hintLabel = "HINT: ";
+                writer.append(ls);
+                colors.style(writer, hintLabel, ColorTheme.HINT_TITLE);
+                writer.append(StyleHelper.formatMessage(hint, LINE_LENGTH - hintLabel.length(), colors));
+                writer.append(ls);
+            });
 
             return writer.toString();
         }

smithy-cli/src/test/java/software/amazon/smithy/cli/commands/PrettyAnsiValidationFormatterTest.java

@@ -51,23 +51,60 @@ public void formatsEventsWithNoColors() {
     }
 
     @Test
-    public void formatsEventsWithColors() {
-        PrettyAnsiValidationFormatter pretty = createFormatter(AnsiColorFormatter.FORCE_COLOR);
-        String formatted = formatTestEventWithSeverity(pretty, Severity.ERROR);
+    public void formatsEventsWithHintWithNoColors() {
+        PrettyAnsiValidationFormatter pretty = createFormatter(AnsiColorFormatter.NO_COLOR);
+        String formatted = formatTestEventWithSeverity(pretty, Severity.ERROR, "Some hint");
 
         assertThat(formatted, equalTo(
                 "\n"
-                + "\u001B[31m── \u001B[0m\u001B[41;30m ERROR \u001B[0m\u001B[31m ───────────────────────────────────────────────────────────────── \u001B[0mFoo\n"
-                + "\u001B[90mShape: \u001B[0m\u001B[95msmithy.example#Foo\u001B[0m\n"
-                + "\u001B[90mFile:  \u001B[0m\u001B[90mbuild/resources/test/software/amazon/smithy/cli/commands/valid-model.smithy:5:1\u001B[0m\n"
+                + "──  ERROR  ───────────────────────────────────────────────────────────────── Foo\n"
+                + "Shape: smithy.example#Foo\n"
+                + "File:  build/resources/test/software/amazon/smithy/cli/commands/valid-model.smithy:5:1\n"
                 + "\n"
-                + "\u001B[90m4| \u001B[0m\n"
-                + "\u001B[90m5| \u001B[0mresource Foo {\n"
-                + "\u001B[90m |\u001B[0m \u001B[31m^\u001B[0m\n"
+                + "4| \n"
+                + "5| resource Foo {\n"
+                + " | ^\n"
                 + "\n"
-                + "Hello, \u001B[36mthere\u001B[0m\n"));
+                + "Hello, `there`\n\n"
+                + "HINT: Some hint\n")); // keeps ticks because formatting is disabled.
+    }
+
+    @Test
+    public void formatsEventsWithColors() {
+        PrettyAnsiValidationFormatter pretty = createFormatter(AnsiColorFormatter.FORCE_COLOR);
+        String formatted = formatTestEventWithSeverity(pretty, Severity.ERROR);
+
+        assertThat(formatted, equalTo(
+            "\n"
+            + "\u001B[31m── \u001B[0m\u001B[41;30m ERROR \u001B[0m\u001B[31m ───────────────────────────────────────────────────────────────── \u001B[0mFoo\n"
+            + "\u001B[90mShape: \u001B[0m\u001B[95msmithy.example#Foo\u001B[0m\n"
+            + "\u001B[90mFile:  \u001B[0m\u001B[90mbuild/resources/test/software/amazon/smithy/cli/commands/valid-model.smithy:5:1\u001B[0m\n"
+            + "\n"
+            + "\u001B[90m4| \u001B[0m\n"
+            + "\u001B[90m5| \u001B[0mresource Foo {\n"
+            + "\u001B[90m |\u001B[0m \u001B[31m^\u001B[0m\n"
+            + "\n"
+            + "Hello, \u001B[36mthere\u001B[0m\n"));
     }
 
+    @Test
+    public void formatsEventsWithHintWithColors() {
+        PrettyAnsiValidationFormatter pretty = createFormatter(AnsiColorFormatter.FORCE_COLOR);
+        String formatted = formatTestEventWithSeverity(pretty, Severity.ERROR, "Some hint");
+
+        assertThat(formatted, equalTo(
+            "\n"
+            + "\u001B[31m── \u001B[0m\u001B[41;30m ERROR \u001B[0m\u001B[31m ───────────────────────────────────────────────────────────────── \u001B[0mFoo\n"
+            + "\u001B[90mShape: \u001B[0m\u001B[95msmithy.example#Foo\u001B[0m\n"
+            + "\u001B[90mFile:  \u001B[0m\u001B[90mbuild/resources/test/software/amazon/smithy/cli/commands/valid-model.smithy:5:1\u001B[0m\n"
+            + "\n"
+            + "\u001B[90m4| \u001B[0m\n"
+            + "\u001B[90m5| \u001B[0mresource Foo {\n"
+            + "\u001B[90m |\u001B[0m \u001B[31m^\u001B[0m\n"
+            + "\n"
+            + "Hello, \u001B[36mthere\u001B[0m\n\n"
+            + "\u001B[92mHINT: \u001B[0mSome hint\n"));
+    }
     @Test
     public void doesNotIncludeSourceLocationNoneInOutput() {
         PrettyAnsiValidationFormatter pretty = createFormatter(AnsiColorFormatter.NO_COLOR);
@@ -116,12 +153,17 @@ private PrettyAnsiValidationFormatter createFormatter(ColorFormatter colors) {
     }
 
     private String formatTestEventWithSeverity(PrettyAnsiValidationFormatter pretty, Severity severity) {
+        return formatTestEventWithSeverity(pretty, severity, null);
+    }
+
+    private String formatTestEventWithSeverity(PrettyAnsiValidationFormatter pretty, Severity severity, String hint) {
         Model model = Model.assembler().addImport(getClass().getResource("valid-model.smithy")).assemble().unwrap();
         ValidationEvent event = ValidationEvent.builder()
                 .id("Foo")
                 .severity(severity)
                 .shape(model.expectShape(ShapeId.from("smithy.example#Foo")))
                 .message("Hello, `there`")
+                .hint(hint)
                 .build();
         return normalizeLinesAndFiles(pretty.format(event));
     }

smithy-model/src/main/java/software/amazon/smithy/model/loader/LoaderTraitMap.java

@@ -38,6 +38,7 @@
 final class LoaderTraitMap {
 
     private static final Logger LOGGER = Logger.getLogger(LoaderTraitMap.class.getName());
+    private static final String UNRESOLVED_TRAIT_SUFFIX = ".UnresolvedTrait";
 
     private final TraitFactory traitFactory;
     private final Map<ShapeId, Map<ShapeId, Node>> traits = new HashMap<>();
@@ -114,7 +115,7 @@ private void validateTraitIsKnown(ShapeId target, ShapeId traitId, Trait trait,
         if (!shapeMap.isRootShapeDefined(traitId) && (trait == null || !trait.isSynthetic())) {
             Severity severity = allowUnknownTraits ? Severity.WARNING : Severity.ERROR;
             events.add(ValidationEvent.builder()
-                    .id(Validator.MODEL_ERROR)
+                    .id(Validator.MODEL_ERROR + UNRESOLVED_TRAIT_SUFFIX)
                     .severity(severity)
                     .sourceLocation(sourceLocation)
                     .shapeId(target)

smithy-model/src/main/java/software/amazon/smithy/model/loader/ModelAssembler.java

@@ -50,6 +50,8 @@
 import software.amazon.smithy.model.validation.Severity;
 import software.amazon.smithy.model.validation.ValidatedResult;
 import software.amazon.smithy.model.validation.ValidationEvent;
+import software.amazon.smithy.model.validation.ValidationEventDecorator;
+import software.amazon.smithy.model.validation.ValidationEventDecoratorFactory;
 import software.amazon.smithy.model.validation.Validator;
 import software.amazon.smithy.model.validation.ValidatorFactory;
 import software.amazon.smithy.utils.Pair;
@@ -93,9 +95,11 @@ public final class ModelAssembler {
 
     private TraitFactory traitFactory;
     private ValidatorFactory validatorFactory;
+    private ValidationEventDecoratorFactory validationEventDecoratorFactory;
     private boolean disableValidation;
     private final Map<String, Supplier<InputStream>> inputStreamModels = new LinkedHashMap<>();
     private final List<Validator> validators = new ArrayList<>();
+    private final List<ValidationEventDecorator> validationEventDecorators = new ArrayList<>();
     private final List<Node> documentNodes = new ArrayList<>();
     private final List<Model> mergeModels = new ArrayList<>();
     private final List<Shape> shapes = new ArrayList<>();
@@ -111,6 +115,12 @@ static final class LazyTraitFactoryHolder {
         static final TraitFactory INSTANCE = TraitFactory.createServiceFactory(ModelAssembler.class.getClassLoader());
     }
 
+    // Lazy initialization holder class idiom to hold a default event validation decorator factory.
+    static final class LazyValidationEventDecoratorFactoryHolder {
+        static final ValidationEventDecoratorFactory INSTANCE =
+            ValidationEventDecoratorFactory.createServiceFactory(ModelAssembler.class.getClassLoader());
+    }
+
     /**
      * Creates a copy of the current model assembler.
      *
@@ -120,8 +130,10 @@ public ModelAssembler copy() {
         ModelAssembler assembler = new ModelAssembler();
         assembler.traitFactory = traitFactory;
         assembler.validatorFactory = validatorFactory;
+        assembler.validationEventDecoratorFactory = validationEventDecoratorFactory;
         assembler.inputStreamModels.putAll(inputStreamModels);
         assembler.validators.addAll(validators);
+        assembler.validationEventDecorators.addAll(validationEventDecorators);
         assembler.documentNodes.addAll(documentNodes);
         assembler.mergeModels.addAll(mergeModels);
         assembler.shapes.addAll(shapes);
@@ -165,6 +177,7 @@ public ModelAssembler reset() {
         mergeModels.clear();
         inputStreamModels.clear();
         validators.clear();
+        validationEventDecorators.clear();
         documentNodes.clear();
         disablePrelude = false;
         disableValidation = false;
@@ -198,6 +211,22 @@ public ModelAssembler validatorFactory(ValidatorFactory validatorFactory) {
         return this;
     }
 
+    /**
+     * Sets a custom {@link ValidationEventDecoratorFactory} used to resolve validation event decorator definitions.
+     *
+     * <p>Note that if you do not provide an explicit decoratorFactory, a
+     * default factory is utilized that uses service discovery.
+     *
+     * @param validationEventDecoratorFactory ValidationEventDecorator factory to use.
+     * @return Returns the assembler.
+     */
+    public ModelAssembler validationEventDecoratorFactory(
+        ValidationEventDecoratorFactory validationEventDecoratorFactory
+    ) {
+        this.validationEventDecoratorFactory = Objects.requireNonNull(validationEventDecoratorFactory);
+        return this;
+    }
+
     /**
      * Registers a validator to be used when validating the model.
      *
@@ -209,6 +238,17 @@ public ModelAssembler addValidator(Validator validator) {
         return this;
     }
 
+    /**
+     * Registers a validation event decorator to be used when validating the model.
+     *
+     * @param decorator Decorator to register.
+     * @return Returns the assembler.
+     */
+    public ModelAssembler addValidationEventDecorator(ValidationEventDecorator decorator) {
+        validationEventDecorators.add(Objects.requireNonNull(decorator));
+        return this;
+    }
+
     /**
      * Adds a string containing an unparsed model to the assembler.
      *
@@ -509,6 +549,9 @@ public ValidatedResult<Model> assemble() {
         if (traitFactory == null) {
             traitFactory = LazyTraitFactoryHolder.INSTANCE;
         }
+        if (validationEventDecoratorFactory == null) {
+            validationEventDecoratorFactory = LazyValidationEventDecoratorFactoryHolder.INSTANCE;
+        }
 
         Model prelude = disablePrelude ? null : Prelude.getPreludeModel();
         LoadOperationProcessor processor = new LoadOperationProcessor(
@@ -572,7 +615,7 @@ public ValidatedResult<Model> assemble() {
         // If ERROR validation events occur while loading, then performing more
         // granular semantic validation will only obscure the root cause of errors.
         if (LoaderUtils.containsErrorEvents(events)) {
-            return returnOnlyErrors(transformed, events);
+            return returnOnlyErrors(transformed, events, resolveDecorators());
         }
 
         if (disableValidation) {
@@ -587,23 +630,36 @@ public ValidatedResult<Model> assemble() {
         }
     }
 
+    private List<ValidationEventDecorator> resolveDecorators() {
+        List<ValidationEventDecorator> resolvedDecorators =
+            new ArrayList<>(validationEventDecoratorFactory.loadDecorators());
+        resolvedDecorators.addAll(validationEventDecorators);
+        return resolvedDecorators;
+    }
+
     private void addMetadataToProcessor(Map<String, Node> metadataMap, LoadOperationProcessor processor) {
         for (Map.Entry<String, Node> entry : metadataMap.entrySet()) {
             processor.accept(new LoadOperation.PutMetadata(Version.UNKNOWN, entry.getKey(), entry.getValue()));
         }
     }
 
-    private ValidatedResult<Model> returnOnlyErrors(Model model, List<ValidationEvent> events) {
-        return new ValidatedResult<>(model, events.stream()
-                .filter(event -> event.getSeverity() == Severity.ERROR)
-                .collect(Collectors.toList()));
+    private ValidatedResult<Model> returnOnlyErrors(
+        Model model,
+        List<ValidationEvent> events,
+        List<ValidationEventDecorator> decorators
+    ) {
+        List<ValidationEvent> filteredEvents = events.stream()
+                  .filter(event -> event.getSeverity() == Severity.ERROR)
+                  .collect(Collectors.toList());
+        return new ValidatedResult<>(model, ModelValidator.decorateEvents(decorators, filteredEvents));
     }
 
     private ValidatedResult<Model> validate(Model model, List<ValidationEvent> events) {
         // Validate the model based on the explicit validators and model metadata.
         // Note the ModelValidator handles emitting events to the validationEventListener.
         List<ValidationEvent> mergedEvents = new ModelValidator()
                 .validators(validators)
+                .validationEventDecorators(resolveDecorators())
                 .validatorFactory(validatorFactory)
                 .eventListener(validationEventListener)
                 .includeEvents(events)