From 5175f564f954de9a74f36b33a1a635678e747f27 Mon Sep 17 00:00:00 2001
From: Beka Westberg <bwestberg@google.com>
Date: Wed, 28 Feb 2024 19:34:19 +0000
Subject: [PATCH 1/2] fix: shouldPreventMove not being respected

---
 core/block_dragger.ts | 56 +++++++++++++++++++++++++++++++++++--------
 1 file changed, 46 insertions(+), 10 deletions(-)

diff --git a/core/block_dragger.ts b/core/block_dragger.ts
index 8d57344ea2e..c2acb08b64e 100644
--- a/core/block_dragger.ts
+++ b/core/block_dragger.ts
@@ -71,8 +71,18 @@ export class BlockDragger implements IBlockDragger {
 
   /** Whether the block would be deleted if dropped immediately. */
   protected wouldDeleteBlock_ = false;
+
   protected startXY_: Coordinate;
 
+  /** The parent block at the start of the drag. */
+  private startParentConn: RenderedConnection | null = null;
+
+  /**
+   * The child block at the start of the drag. Only gets set if
+   * `healStack` is true.
+   */
+  private startChildConn: RenderedConnection | null = null;
+
   /**
    * @deprecated To be removed in v11. Updating icons is now handled by the
    *     block's `moveDuringDrag` method.
@@ -137,6 +147,13 @@ export class BlockDragger implements IBlockDragger {
     blockAnimation.disconnectUiStop();
 
     if (this.shouldDisconnect_(healStack)) {
+      this.startParentConn =
+        this.draggingBlock_.outputConnection?.targetConnection ??
+        this.draggingBlock_.previousConnection?.targetConnection;
+      if (healStack) {
+        this.startChildConn =
+          this.draggingBlock_.nextConnection?.targetConnection;
+      }
       this.disconnectBlock_(healStack, currentDragDeltaXY);
     }
     this.draggingBlock_.setDragging(true);
@@ -424,17 +441,10 @@ export class BlockDragger implements IBlockDragger {
         .getLayerManager()
         ?.moveOffDragLayer(this.draggingBlock_, layers.BLOCK);
       this.draggingBlock_.setDragging(false);
-      if (delta) {
-        // !preventMove
+      if (preventMove) {
+        this.moveToOriginalPosition();
+      } else if (delta) {
         this.updateBlockAfterMove_();
-      } else {
-        // Blocks dragged directly from a flyout may need to be bumped into
-        // bounds.
-        bumpObjects.bumpIntoBounds(
-          this.draggingBlock_.workspace,
-          this.workspace_.getMetricsManager().getScrollMetrics(true),
-          this.draggingBlock_,
-        );
       }
     }
     // Must dispose after `updateBlockAfterMove_` is called to not break the
@@ -445,6 +455,32 @@ export class BlockDragger implements IBlockDragger {
     eventUtils.setGroup(false);
   }
 
+  /**
+   * Moves the dragged block back to its original position before the start of
+   * the drag. Reconnects any parent and child blocks.\
+   */
+  private moveToOriginalPosition() {
+    this.startChildConn?.connect(this.draggingBlock_.nextConnection);
+    if (this.startParentConn) {
+      switch (this.startParentConn?.type) {
+        case ConnectionType.INPUT_VALUE:
+          this.startParentConn?.connect(this.draggingBlock_.outputConnection);
+          break;
+        case ConnectionType.NEXT_STATEMENT:
+          this.startParentConn?.connect(this.draggingBlock_.previousConnection);
+      }
+    } else {
+      this.draggingBlock_.moveTo(this.startXY_, ['drag']);
+      // Blocks dragged directly from a flyout may need to be bumped into
+      // bounds.
+      bumpObjects.bumpIntoBounds(
+        this.draggingBlock_.workspace,
+        this.workspace_.getMetricsManager().getScrollMetrics(true),
+        this.draggingBlock_,
+      );
+    }
+  }
+
   /**
    * Calculates the drag delta and new location values after a block is dragged.
    *

From 9a7ec3a3beda0ef31ee24e5807a8795c0d88d9e7 Mon Sep 17 00:00:00 2001
From: Beka Westberg <bwestberg@google.com>
Date: Tue, 5 Mar 2024 21:50:30 +0000
Subject: [PATCH 2/2] fix: PR comments

---
 core/block_dragger.ts | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/core/block_dragger.ts b/core/block_dragger.ts
index c2acb08b64e..972c5fa2bea 100644
--- a/core/block_dragger.ts
+++ b/core/block_dragger.ts
@@ -457,17 +457,17 @@ export class BlockDragger implements IBlockDragger {
 
   /**
    * Moves the dragged block back to its original position before the start of
-   * the drag. Reconnects any parent and child blocks.\
+   * the drag. Reconnects any parent and child blocks.
    */
   private moveToOriginalPosition() {
     this.startChildConn?.connect(this.draggingBlock_.nextConnection);
     if (this.startParentConn) {
-      switch (this.startParentConn?.type) {
+      switch (this.startParentConn.type) {
         case ConnectionType.INPUT_VALUE:
-          this.startParentConn?.connect(this.draggingBlock_.outputConnection);
+          this.startParentConn.connect(this.draggingBlock_.outputConnection);
           break;
         case ConnectionType.NEXT_STATEMENT:
-          this.startParentConn?.connect(this.draggingBlock_.previousConnection);
+          this.startParentConn.connect(this.draggingBlock_.previousConnection);
       }
     } else {
       this.draggingBlock_.moveTo(this.startXY_, ['drag']);