fix: have the connection previewer use the registry (#7800)

core/block_dragger.ts

@@ -31,7 +31,6 @@ import {hasBubble} from './interfaces/i_has_bubble.js';
 import * as deprecation from './utils/deprecation.js';
 import * as layers from './layers.js';
 import {ConnectionType, IConnectionPreviewer} from './blockly.js';
-import {InsertionMarkerPreviewer} from './connection_previewers/insertion_marker_previewer.js';
 import {RenderedConnection} from './rendered_connection.js';
 import {config} from './config.js';
 import {ComponentManager} from './component_manager.js';
@@ -86,12 +85,14 @@ export class BlockDragger implements IBlockDragger {
    */
   constructor(block: BlockSvg, workspace: WorkspaceSvg) {
     this.draggingBlock_ = block;
-
-    // TODO: have this access the registry instead.
-    this.connectionPreviewer = new InsertionMarkerPreviewer(block);
-
     this.workspace_ = workspace;
 
+    const previewerConstructor = registry.getClassFromOptions(
+      registry.Type.CONNECTION_PREVIEWER,
+      this.workspace_.options,
+    );
+    this.connectionPreviewer = new previewerConstructor!(block);
+
     /**
      * The location of the top left corner of the dragging block at the
      * beginning of the drag in workspace coordinates.

core/blockly.ts

@@ -128,6 +128,7 @@ import {Input} from './inputs/input.js';
 import {inputTypes} from './inputs/input_types.js';
 import * as inputs from './inputs.js';
 import {InsertionMarkerManager} from './insertion_marker_manager.js';
+import {InsertionMarkerPreviewer} from './connection_previewers/insertion_marker_previewer.js';
 import {IASTNodeLocation} from './interfaces/i_ast_node_location.js';
 import {IASTNodeLocationSvg} from './interfaces/i_ast_node_location_svg.js';
 import {IASTNodeLocationWithBlock} from './interfaces/i_ast_node_location_with_block.js';
@@ -607,6 +608,7 @@ export {IMovable};
 export {Input};
 export {inputs};
 export {InsertionMarkerManager};
+export {InsertionMarkerPreviewer};
 export {IObservable, isObservable};
 export {IPaster, isPaster};
 export {IPositionable};

core/connection_previewers/insertion_marker_previewer.ts

@@ -11,6 +11,7 @@ import {WorkspaceSvg} from '../workspace_svg.js';
 import * as eventUtils from '../events/utils.js';
 import * as constants from '../constants.js';
 import * as renderManagement from '../render_management.js';
+import * as registry from '../registry.js';
 
 /**
  * An error message to throw if the block created by createMarkerBlock_ is
@@ -247,3 +248,9 @@ export class InsertionMarkerPreviewer implements IConnectionPreviewer {
     this.hidePreview();
   }
 }
+
+registry.register(
+  registry.Type.CONNECTION_PREVIEWER,
+  registry.DEFAULT,
+  InsertionMarkerPreviewer,
+);