openapi3: fix validation of non-empty interface slice value against a…

…rray schema (#752)

Resolves #751

openapi3/schema.go

@@ -1120,6 +1120,17 @@ func (schema *Schema) visitJSON(settings *schemaValidationSettings, value interf
 			return schema.visitJSONObject(settings, values)
 		}
 	}
+
+	// Catch slice of non-empty interface type
+	if reflect.TypeOf(value).Kind() == reflect.Slice {
+		valueR := reflect.ValueOf(value)
+		newValue := make([]interface{}, valueR.Len())
+		for i := 0; i < valueR.Len(); i++ {
+			newValue[i] = valueR.Index(i).Interface()
+		}
+		return schema.visitJSONArray(settings, newValue)
+	}
+
 	return &SchemaError{
 		Value:                 value,
 		Schema:                schema,

openapi3/schema_test.go

@@ -1354,3 +1354,15 @@ enum:
 	err = schema.VisitJSON(map[string]interface{}{"d": "e"})
 	require.Error(t, err)
 }
+
+func TestIssue751(t *testing.T) {
+	schema := &Schema{
+		Type:        "array",
+		UniqueItems: true,
+		Items:       NewStringSchema().NewRef(),
+	}
+	validData := []string{"foo", "bar"}
+	invalidData := []string{"foo", "foo"}
+	require.NoError(t, schema.VisitJSON(validData))
+	require.ErrorContains(t, schema.VisitJSON(invalidData), "duplicate items found")
+}