fix: Fix bug that could caused variable map to be left in an inconsistent state. (#9339)

Author: gonfunko

core/variable_map.ts

@@ -112,7 +112,11 @@ export class VariableMap
     const oldType = variable.getType();
     if (oldType === newType) return variable;
 
-    this.variableMap.get(variable.getType())?.delete(variable.getId());
+    const oldTypeVariables = this.variableMap.get(oldType);
+    oldTypeVariables?.delete(variable.getId());
+    if (oldTypeVariables?.size === 0) {
+      this.variableMap.delete(oldType);
+    }
     variable.setType(newType);
     const newTypeVariables =
       this.variableMap.get(newType) ??

tests/mocha/variable_map_test.js

@@ -258,6 +258,13 @@ suite('Variable Map', function () {
         assert.deepEqual(newTypeVariables, [variable]);
         assert.equal(variable.getType(), '');
       });
+
+      test('removes the type from the map when the last instance is changed', function () {
+        const var1 = this.variableMap.createVariable('name1', 'type1');
+        const var2 = this.variableMap.createVariable('name2', 'type2');
+        this.variableMap.changeVariableType(var1, 'type2');
+        assert.deepEqual(this.variableMap.getTypes(), ['type2']);
+      });
     },
   );