theonedev/onedev · error · ExplicitException

Property 'type' is reserved (class: X)

Error message

Property 'type' is reserved (class: X)

What it means

In generated JSON schemas, the 'type' property name is reserved for polymorphic type discrimination. processBean iterates a bean's properties and throws this ExplicitException if any property is literally named 'type', since it would clash with the discriminator.

Source

Thrown at server-core/src/main/java/io/onedev/server/ai/BuildSpecSchema.java:221

                            lastValueBytes = SerializationUtils.serialize((Serializable) value);
                            valueBytesMap.put(property.getPropertyName(), lastValueBytes);
                        } else if (!Arrays.equals(lastValueBytes, SerializationUtils.serialize((Serializable) value))) {
                            excludedProperties.add(property.getPropertyName());
                        }
                    }
                }
            }                        
        }
        if (bean == null) {
            bean = newBean(beanClass);
        }
        
        var dependents = new ArrayList<Pair<PropertyDescriptor, DependsOn[]>>();
        for (var groupProperties: beanDescriptor.getProperties().values()) {
            for (var property: groupProperties) {
                if (!excludedProperties.contains(property.getPropertyName()) && processedProperties.add(property.getPropertyName())) {
                    if (property.getPropertyName().equals("type"))
                        throw new ExplicitException("Property 'type' is reserved (class: " + beanClass.getName() + ")");
                    var dependsOns = property.getPropertyGetter().getAnnotationsByType(DependsOn.class);
                    if (dependsOns.length != 0) {
                        dependents.add(new Pair<>(property, dependsOns));
                    } else {
                        if (property.isPropertyRequired())
                            requiredNode.add(property.getPropertyName()); 
                        var propNode = new HashMap<String, Object>();
                        propsNode.put(property.getPropertyName(), propNode);
                        processProperty(propNode, bean, property);
                    }
                }
            }
        }
        if (!dependents.isEmpty()) {
            var allOfNode = new ArrayList<Map<String, Object>>();
            currentNode.put("allOf", allOfNode);
            for (var dependent: dependents) {
                var allOfItemNode = new HashMap<String, Object>();

View on GitHub (pinned to d44925c47c)

Solutions

1. Rename the property to something else (e.g. 'executorType', 'kind') in the bean class.
2. If 'type' must appear in the output YAML, keep the Java property name different and add an @Property/description mapping as supported by the spec framework.
3. Exclude the property from schema processing if your version exposes an exclusion mechanism (excludedProperties) for it.

Example fix

// before
private String type;
public String getType() { return type; }
// after
private String executorType;
public String getExecutorType() { return executorType; }

for (PropertyDescriptor p : beanProperties) {
    if (p.getPropertyName().equals("type"))
        throw new IllegalStateException("'type' is reserved: " + beanClass.getName());
}

try {
    schema = BuildSpecSchema.generate(specClass);
} catch (ExplicitException e) {
    if (e.getMessage().contains("Property 'type' is reserved")) {
        // rename the property in the class indicated by the message
    }
}

When it happens

Trigger: Defining a build spec bean class (processed via processType/processPolymorphic) that has a getter/property named 'type' which is not in the excludedProperties set, then generating the schema.

Common situations: Custom spec classes mirroring external YAML formats that use 'type' as a field name, or porting an existing config class into OneDev's build spec model without renaming the property.

Understand the failure class

Background: Schema validation failed / invalid input schema: payload rejected because its shape doesn't match the expected schema — this error's family across 28 libraries.

Related errors

• Unknown collection element class (bean: X, property: Y)
• Unsupported type: X
• Dependency property not found: X
• Malformed build spec
• Circular template usages (

AI-assisted analysis of theonedev/onedev@d44925c47c (2026-09-06). Data as JSON: /api/errors/25ba7508b80ea414. Report an issue: GitHub.