[Bug] [UI] Clicking edit on a task throws "Cannot read properties of undefined (reading 'releaseState')" when workflowDefinition is undefined

[nanxiuzi]

Summary

When clicking "Edit" on a task node in the DAG editor, the browser console throws Uncaught (in promise) TypeError: Cannot read properties of undefined (reading 'releaseState') and the page stops rendering. Two computed properties in dag/index.tsx (startDisplay and menuDisplay) access props.definition.workflowDefinition.releaseState without null-checking workflowDefinition.

Expected Behavior

Clicking "Edit" on a task should open the task editor without throwing. If workflowDefinition is undefined (e.g., the workflow is in a transient state), the relevant UI controls (start button, "other" menu) should be hidden, but the page should keep rendering.

How to Reproduce

1. Open a workflow definition that contains task nodes.
2. Get into a state where props.definition.workflowDefinition is undefined. This can happen when:
   • The workflow definition has not been saved yet (draft state)
   • The workflow definition was deleted but task instances still reference it
   • The API response is missing the workflowDefinition field for some reason
3. Right-click a task node and click "Edit".
4. Observe the browser console: Uncaught (in promise) TypeError: Cannot read properties of undefined (reading 'releaseState') at index-XXX.js:1:NNNN.
5. The DAG page stops rendering (or part of the right-click menu doesn't appear).

Root Cause

In dolphinscheduler-ui/src/views/projects/workflow/components/dag/index.tsx, two computed properties use the TypeScript non-null assertion operator on props.definition but skip any null check on workflowDefinition:

// Line 126-135
const startDisplay = computed(() => {
  if (props.definition) {
    return (
      route.name === 'workflow-definition-detail' &&
      props.definition!.workflowDefinition.releaseState === 'ONLINE'
    )
  } else {
    return false
  }
})

// Line 143-156
const menuDisplay = computed(() => {
  if (props.instance) {
    return (
      props.instance.state === 'SUCCESS' ||
      props.instance.state === 'PAUSE' ||
      props.instance.state === 'FAILURE' ||
      props.instance.state === 'STOP'
    )
  } else if (props.definition) {
    return props.definition!.workflowDefinition.releaseState === 'OFFLINE'
  } else {
    return false
  }
})

The ! is a TypeScript-only non-null assertion — it has no runtime effect. When props.definition.workflowDefinition is undefined, accessing .releaseState throws TypeError: Cannot read properties of undefined (reading 'releaseState').

Note: dag-toolbar.tsx (lines 276 and 512) already uses the safe pattern props.definition?.workflowDefinition?.releaseState, so this is an inconsistency within the same module.

Environment

• DolphinScheduler 3.4.2 release (also reproduced on the latest dev branch, commit 3752346650)
• Browser: any (the error is a JavaScript runtime error, not browser-specific)

[SbloodyS]

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