fix: Fire deletion events when clearing variables. (#6827)

https://groups.google.com/g/blockly/c/l_vUnrGSJ0M

core/variable_map.ts

@@ -44,10 +44,18 @@ export class VariableMap {
   /** @param workspace The workspace this map belongs to. */
   constructor(public workspace: Workspace) {}
 
-  /** Clear the variable map. */
+  /** Clear the variable map.  Fires events for every deletion. */
   clear() {
-    this.variableMap.clear();
+    for (const variables of this.variableMap.values()) {
+      while (variables.length > 0) {
+        this.deleteVariable(variables[0]);
+      }
+    }
+    if (this.variableMap.size !== 0) {
+      throw Error('Non-empty variable map');
+    }
   }
+
   /* Begin functions for renaming variables. */
   /**
    * Rename the given variable by updating its name in the variable map.
@@ -142,6 +150,7 @@ export class VariableMap {
     // And remove it from the list.
     arrayUtils.removeElem(this.variableMap.get(type)!, variable);
   }
+
   /* End functions for renaming variables. */
   /**
    * Create a variable with a given name, optional type, and optional ID.
@@ -187,6 +196,7 @@ export class VariableMap {
 
     return variable;
   }
+
   /* Begin functions for variable deletion. */
   /**
    * Delete a variable.
@@ -203,6 +213,9 @@ export class VariableMap {
           variableList.splice(i, 1);
           eventUtils.fire(
               new (eventUtils.get(eventUtils.VAR_DELETE))(variable));
+          if (variableList.length === 0) {
+            this.variableMap.delete(variable.type);
+          }
           return;
         }
       }
@@ -306,7 +319,7 @@ export class VariableMap {
    * @returns The variable with the given ID.
    */
   getVariableById(id: string): VariableModel|null {
-    for (const [_key, variables] of this.variableMap) {
+    for (const variables of this.variableMap.values()) {
       for (const variable of variables) {
         if (variable.getId() === id) {
           return variable;