Lower input validation severity for error examples

docs/source-2.0/spec/documentation-traits.rst

@@ -139,9 +139,10 @@ Each ``example`` trait value is a structure with the following members:
       - Provides an error shape ID and example error parameters for the
         operation.
 
-The values provided for the ``input`` and ``output`` members MUST be
-compatible with the shapes and constraints of the corresponding structure.
-These values use the same semantics and format as
+When ``input`` and ``output`` members are present, both MUST be compatible
+with the shapes and constraints of the corresponding structure. When ``input``
+and ``error`` members are present, any validation events for the ``input`` will
+be emitted as a ``WARNING``. These values use the same semantics and format as
 :ref:`custom trait values <trait-node-values>`.
 
 A value for ``output`` or ``error`` SHOULD be provided. However, both

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

@@ -25,6 +25,7 @@
 import software.amazon.smithy.model.traits.ExamplesTrait;
 import software.amazon.smithy.model.validation.AbstractValidator;
 import software.amazon.smithy.model.validation.NodeValidationVisitor;
+import software.amazon.smithy.model.validation.Severity;
 import software.amazon.smithy.model.validation.ValidationEvent;
 
 /**
@@ -47,15 +48,23 @@ private List<ValidationEvent> validateExamples(Model model, OperationShape shape
         List<ExamplesTrait.Example> examples = trait.getExamples();
 
         for (ExamplesTrait.Example example : examples) {
+            boolean isOutputDefined = example.getOutput().isPresent();
+            boolean isErrorDefined = example.getError().isPresent();
+
             model.getShape(shape.getInputShape()).ifPresent(input -> {
                 NodeValidationVisitor validator = createVisitor(
                         "input", example.getInput(), model, shape, example);
-                events.addAll(input.accept(validator));
+                List<ValidationEvent> inputValidationEvents = input.accept(validator);
+                // Lower severity of input validation if this is an example of an error.
+                if (isErrorDefined) {
+                    for (ValidationEvent event : inputValidationEvents) {
+                        events.add(event.toBuilder().severity(Severity.WARNING).build());
+                    }
+                } else {
+                    events.addAll(inputValidationEvents);
+                }
             });
 
-            boolean isOutputDefined = example.getOutput().isPresent();
-            boolean isErrorDefined = example.getError().isPresent();
-
             if (isOutputDefined && isErrorDefined) {
                 events.add(error(shape, trait, String.format(
                         "Example: `%s` has both output and error defined, only one should be present.",

smithy-model/src/test/resources/software/amazon/smithy/model/errorfiles/validators/examples-trait-validator.errors

@@ -6,3 +6,4 @@
 [WARNING] ns.foo#Operation: Example output of `Testing 2`: Invalid structure member `additional` found for `ns.foo#OperationOutput` | ExamplesTrait
 [ERROR] ns.foo#Operation: Example output of `Testing 2`: Missing required structure member `bam` for `ns.foo#OperationOutput` | ExamplesTrait
 [WARNING] ns.foo#Operation: Example error of `Testing 1`: Invalid structure member `extra` found for `ns.foo#OperationError` | ExamplesTrait
+[WARNING] ns.foo#Operation: Example input of `Testing 4`: Missing required structure member `foo` for `ns.foo#OperationInput` | ExamplesTrait

smithy-model/src/test/resources/software/amazon/smithy/model/errorfiles/validators/examples-trait-validator.json

@@ -53,6 +53,18 @@
                                 "bat": "baz"
                             }
                         }
+                    },
+                    {
+                        "title": "Testing 4",
+                        "input": {
+                            "baz": "baz"
+                        },
+                        "error": {
+                            "shapeId": "ns.foo#OperationError",
+                            "content": {
+                                "bat": "baz"
+                            }
+                        }
                     }
                 ]
             }