fix: Fix bug that prevented the first block change event in a flyout from being dispatched

core/flyout_base.ts

@@ -135,6 +135,12 @@ export abstract class Flyout
    */
   private reflowWrapper: ((e: AbstractEvent) => void) | null = null;
 
+  /**
+   * If true, prevents the reflow wrapper from running. Used to prevent infinite
+   * recursion.
+   */
+  private inhibitReflowWrapper = false;
+
   /**
    * List of flyout elements.
    */
@@ -647,6 +653,7 @@ export abstract class Flyout
     // accommodates e.g. resizing a non-autoclosing flyout in response to the
     // user typing long strings into fields on the blocks in the flyout.
     this.reflowWrapper = (event) => {
+      if (this.inhibitReflowWrapper) return;
       if (
         event.type === EventType.BLOCK_CHANGE ||
         event.type === EventType.BLOCK_FIELD_INTERMEDIATE_CHANGE
@@ -844,13 +851,9 @@ export abstract class Flyout
    * Reflow flyout contents.
    */
   reflow() {
-    if (this.reflowWrapper) {
-      this.workspace_.removeChangeListener(this.reflowWrapper);
-    }
+    this.inhibitReflowWrapper = true;
     this.reflowInternal_();
-    if (this.reflowWrapper) {
-      this.workspace_.addChangeListener(this.reflowWrapper);
-    }
+    this.inhibitReflowWrapper = false;
   }
 
   /**

tests/mocha/flyout_test.js

@@ -43,6 +43,26 @@ suite('Flyout', function () {
     sharedTestTeardown.call(this);
   });
 
+  suite('workspace change listeners', function () {
+    test('are triggered when a child block changes', function () {
+      let listenerTriggered = false;
+      const listener = (e) => {
+        if (e.type === Blockly.Events.BLOCK_CHANGE) {
+          listenerTriggered = true;
+        }
+      };
+      this.workspace.getFlyout().getWorkspace().addChangeListener(listener);
+      const boolBlock = this.workspace
+        .getFlyout()
+        .getWorkspace()
+        .getBlocksByType('logic_compare')[0];
+      boolBlock.getField('OP').setValue('LTE');
+      this.clock.tick(1000);
+      assert.isTrue(listenerTriggered);
+      this.workspace.getFlyout().getWorkspace().removeChangeListener(listener);
+    });
+  });
+
   suite('position', function () {
     suite('vertical flyout', function () {
       suite('simple flyout', function () {