`workspace.dispose()` throws "Non-empty variable map" error after `changeVariableType`

[michaelnixonau]

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Description

Calling workspace.dispose() after using workspace.getVariableMap().changeVariableType() can trigger a "Non-empty variable map" error when the variable being changed is the last of its original type.

The issue stems from changeVariableType in variable_map.ts. When a variable’s type changes, it is removed from the old type’s map, but the code does not remove the map itself if it becomes empty. As a result, VariableMap.clear() removes all variables but leaves behind the empty map. Its final check if (this.variableMap.size !== 0) then fails, causing the error.

Suggested fix

in variable_map.ts:

 if (oldType === newType) return variable;

 // start of fix -- delete old type map if our var was the last of its type
 const oldTypeVariables = this.variableMap.get(oldType);
 oldTypeVariables?.delete(variable.getId());
 if (oldTypeVariables?.size === 0) {
 this.variableMap.delete(oldType);
 }
 // end of fix

 variable.setType(newType);

Reproduction steps

1. Create a workspace.
2. Create a single variable of a custom type, for example, "typeA".
3. Change the type of this variable to a new type, for instance, "typeB".
4. Attempt to dispose of the workspace.
5. Observe the error thrown from the clear() method in variable_map.ts.

Stack trace

Screenshots

Error: Non-empty variable map
at VariableMap.clear (variable_map.ts:X:X)
at Workspace.dispose (workspace.ts:X:X)
at ...

Browsers

No response