fix: dynamic blocks finalizing connections when children are deleted

plugins/block-dynamic-connection/README.md

@@ -15,7 +15,7 @@ npm install @blockly/block-dynamic-connection --save
 import * as Blockly from 'blockly';
 import * as BlockDynamicConnection from '@blockly/block-dynamic-connection';
 
-const ws = Blockly.inject({
+const myWorkspace = Blockly.inject({
     // options...
     plugins: {
       connectionPreviewer:
@@ -26,6 +26,9 @@ const ws = Blockly.inject({
         ),
     },
   };
+
+// Add the change listener so connections will be finalized on deletion.
+workspace.addChangeListener(BlockDynamicConnection.finalizeConnections);
 ```
 
 ## API

plugins/block-dynamic-connection/src/connection_previewer.ts

@@ -15,7 +15,11 @@
   finalizeConnections(): void;
 }
 
-function blockIsDynamic(block: Blockly.BlockSvg): block is DynamicBlock {
+/**
+ * A type guard that checks if the given block fulfills the DynamicBlock
+ * interface.
+ */
+export function blockIsDynamic(block: Blockly.BlockSvg): block is DynamicBlock {
   return (
     (block as DynamicBlock)['onPendingConnection'] !== undefined &&
     (block as DynamicBlock)['finalizeConnections'] !== undefined

plugins/block-dynamic-connection/src/index.ts

@@ -13,12 +13,28 @@
 import './dynamic_if';
 import './dynamic_text_join';
 import './dynamic_list_create';
-import {decoratePreviewer} from './connection_previewer';
+import {decoratePreviewer, blockIsDynamic} from './connection_previewer';
 
-export {decoratePreviewer};
+export {decoratePreviewer, blockIsDynamic};
 
 export const overrideOldBlockDefinitions = function (): void {
   Blockly.Blocks['lists_create_with'] = Blockly.Blocks['dynamic_list_create'];
   Blockly.Blocks['text_join'] = Blockly.Blocks['dynamic_text_join'];
   Blockly.Blocks['controls_if'] = Blockly.Blocks['dynamic_if'];
 };
+
+/**
+ * Finalizes connections when certain events (such as block deletion) are
+ * detected.
+ */
+export function finalizeConnections(e: Blockly.Events.Abstract) {
+  if (e.type === Blockly.Events.BLOCK_DELETE) {
+    const ws = Blockly.Workspace.getById(e.workspaceId ?? '');
+    if (!ws) return;
+    for (const block of ws.getAllBlocks() as Blockly.BlockSvg[]) {
+      if (blockIsDynamic(block)) {
+        block.finalizeConnections();
+      }
+    }
+  }
+}

plugins/block-dynamic-connection/test/index.ts

@@ -23,7 +23,9 @@ function createWorkspace(
   blocklyDiv: HTMLElement,
   options: Blockly.BlocklyOptions,
 ): Blockly.WorkspaceSvg {
-  return Blockly.inject(blocklyDiv, options);
+  const ws = Blockly.inject(blocklyDiv, options);
+  ws.addChangeListener(BlockDynamicConnection.finalizeConnections);
+  return ws;
 }
 
 document.addEventListener('DOMContentLoaded', function () {