flowable/flowable-engine · error · FlowableException

The deployment contains decisions with the same key (decisio

Error message

The deployment contains decisions with the same key (decision id attribute), this is not allowed

What it means

DmnDeploymentHelper.verifyDecisionTablesDoNotShareKeys enforces that all decisions in one deployment have distinct keys (the DMN <decision id> attribute). A duplicate key makes per-key version resolution ambiguous, so deployment fails with FlowableException.

Source

Thrown at modules/flowable-dmn-engine/src/main/java/org/flowable/dmn/engine/impl/deployer/DmnDeploymentHelper.java:48

import org.flowable.dmn.engine.impl.util.CommandContextUtil;

/**
 * Methods for working with deployments. Much of the actual work of {@link DmnDeployer} is done by orchestrating the different pieces of work this class does; by having them here, we allow other
 * deployers to make use of them.
 */
public class DmnDeploymentHelper {

    /**
     * Verifies that no two decisions share the same key, to prevent database unique index violation.
     * 
     * @throws FlowableException
     *             if any two decisions have the same key
     */
    public void verifyDecisionTablesDoNotShareKeys(Collection<DecisionEntity> decisionTables) {
        Set<String> keySet = new LinkedHashSet<>();
        for (DecisionEntity decisionTable : decisionTables) {
            if (keySet.contains(decisionTable.getKey())) {
                throw new FlowableException(
                        "The deployment contains decisions with the same key (decision id attribute), this is not allowed");
            }
            keySet.add(decisionTable.getKey());
        }
    }

    /**
     * Updates all the decision entities to match the deployment's values for tenant, engine version, and deployment id.
     */
    public void copyDeploymentValuesToDecisions(DmnDeploymentEntity deployment, List<DecisionEntity> decisions) {
        String tenantId = deployment.getTenantId();
        String deploymentId = deployment.getId();

        for (DecisionEntity decision : decisions) {
            // decision inherits the tenant id
            if (tenantId != null) {
                decision.setTenantId(tenantId);
            }

View on GitHub (pinned to d6d39ce1c6)

Solutions

1. Rename the duplicate <decision id="..."> to a unique key within the deployment.
2. Split colliding decisions into separate deployments if they must keep identical keys (versions are per-key across deployments).
3. Lint DMN resources with an XML check for duplicate ids before deploying.
4. If versions differ, ensure each decision's id attribute is unique and reference decisions via DRD accordingly.

Example fix

// before (in .dmn XML)
<decision id="myDecision" name="A">...</decision>
<decision id="myDecision" name="B">...</decision>
// after
<decision id="myDecisionA" name="A">...</decision>
<decision id="myDecisionB" name="B">...</decision>

Set<String> seen = new HashSet<>();
for (String id : allDecisionIdsInResources) {
    if (!seen.add(id)) throw new IllegalStateException("Duplicate decision id: " + id);
}

try {
    repositoryService.createDeployment().addClasspathResource("decision.dmn").deploy();
} catch (FlowableException e) {
    if (e.getMessage().contains("same key")) { /* fix duplicate ids */ }
}

When it happens

Trigger: Deploying a .dmn file (or set of resources) containing two <decision> elements with the same id attribute; merging DMN files that each define a decision with the same id; case-insensitive collisions across included resources in one deployment.

Common situations: Copy-pasting a decision table inside one DMN file to tweak it without renaming the id; concatenating DRD files from different sources that reuse ids like "decision1"; auto-generated DMN from tooling that emits fixed ids.

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

• The deployment contains case definitions with the same key (
• version must be positive
• Required decision <decisionId> is not available
• decision table does not contain a hit policy
• deploymentId is null

AI-assisted analysis of flowable/flowable-engine@d6d39ce1c6 (2026-09-11). Data as JSON: /api/errors/289be803308da2a5. Report an issue: GitHub.