From 43be0edf5d2836ded59d083138674a4fd8b3aa7d Mon Sep 17 00:00:00 2001
From: Aaron Dodson <adodson@google.com>
Date: Thu, 2 Apr 2026 11:01:29 -0700
Subject: [PATCH] fix!: Fix types on `BlockSvg` connections (#9669)

---
 packages/blockly/blocks/text.ts                  |  6 ++++--
 packages/blockly/core/block_svg.ts               |  9 +++------
 .../blockly/core/dragging/block_drag_strategy.ts | 16 +++++++++++-----
 packages/blockly/core/renderers/common/drawer.ts |  2 +-
 4 files changed, 19 insertions(+), 14 deletions(-)

diff --git a/packages/blockly/blocks/text.ts b/packages/blockly/blocks/text.ts
index a7ad5374a..8ab961ee5 100644
--- a/packages/blockly/blocks/text.ts
+++ b/packages/blockly/blocks/text.ts
@@ -757,13 +757,15 @@ const JOIN_MUTATOR_MIXIN = {
       'text_create_join_container',
     ) as BlockSvg;
     containerBlock.initSvg();
-    let connection = containerBlock.getInput('STACK')!.connection!;
+    let connection = containerBlock.getInput('STACK')?.connection;
     for (let i = 0; i < this.itemCount_; i++) {
       const itemBlock = workspace.newBlock(
         'text_create_join_item',
       ) as JoinItemBlock;
       itemBlock.initSvg();
-      connection.connect(itemBlock.previousConnection);
+      if (itemBlock.previousConnection) {
+        connection?.connect(itemBlock.previousConnection);
+      }
       connection = itemBlock.nextConnection;
     }
     return containerBlock;
diff --git a/packages/blockly/core/block_svg.ts b/packages/blockly/core/block_svg.ts
index 666436c1e..051d7ace5 100644
--- a/packages/blockly/core/block_svg.ts
+++ b/packages/blockly/core/block_svg.ts
@@ -160,12 +160,9 @@ export class BlockSvg
   private visuallyDisabled = false;
 
   override workspace: WorkspaceSvg;
-  // TODO(b/109816955): remove '!', see go/strict-prop-init-fix.
-  override outputConnection!: RenderedConnection;
-  // TODO(b/109816955): remove '!', see go/strict-prop-init-fix.
-  override nextConnection!: RenderedConnection;
-  // TODO(b/109816955): remove '!', see go/strict-prop-init-fix.
-  override previousConnection!: RenderedConnection;
+  override outputConnection: RenderedConnection | null = null;
+  override nextConnection: RenderedConnection | null = null;
+  override previousConnection: RenderedConnection | null = null;
 
   private translation = '';
 
diff --git a/packages/blockly/core/dragging/block_drag_strategy.ts b/packages/blockly/core/dragging/block_drag_strategy.ts
index f4578a941..c521e8b11 100644
--- a/packages/blockly/core/dragging/block_drag_strategy.ts
+++ b/packages/blockly/core/dragging/block_drag_strategy.ts
@@ -366,7 +366,7 @@ export class BlockDragStrategy implements IDragStrategy {
           };
         }
 
-        this.startChildConn = nextTargetConn;
+        this.startChildConn = nextTargetConn ?? null;
       }
     }
   }
@@ -627,7 +627,7 @@ export class BlockDragStrategy implements IDragStrategy {
       draggingBlock.outputConnection,
       draggingBlock.previousConnection,
       draggingBlock.nextConnection,
-    ].filter(Boolean); // Removes falsy (null) values.
+    ].filter((c) => !!c); // Removes falsy (null) values.
     const inputConnections: RenderedConnection[] = [];
 
     for (const conn of available) {
@@ -727,14 +727,20 @@ export class BlockDragStrategy implements IDragStrategy {
     this.connectionPreviewer?.hidePreview();
     this.connectionCandidate = null;
 
-    this.startChildConn?.connect(this.block.nextConnection);
+    if (this.block.nextConnection) {
+      this.startChildConn?.connect(this.block.nextConnection);
+    }
     if (this.startParentConn) {
       switch (this.startParentConn.type) {
         case ConnectionType.INPUT_VALUE:
-          this.startParentConn.connect(this.block.outputConnection);
+          if (this.block.outputConnection) {
+            this.startParentConn.connect(this.block.outputConnection);
+          }
           break;
         case ConnectionType.NEXT_STATEMENT:
-          this.startParentConn.connect(this.block.previousConnection);
+          if (this.block.previousConnection) {
+            this.startParentConn.connect(this.block.previousConnection);
+          }
       }
     } else {
       this.block.moveTo(this.startLoc!, ['drag']);
diff --git a/packages/blockly/core/renderers/common/drawer.ts b/packages/blockly/core/renderers/common/drawer.ts
index c474bc8c3..f70462fa2 100644
--- a/packages/blockly/core/renderers/common/drawer.ts
+++ b/packages/blockly/core/renderers/common/drawer.ts
@@ -422,7 +422,7 @@ export class Drawer {
       const x =
         this.info_.startX + this.info_.outputConnection.connectionOffsetX;
       const connX = this.info_.RTL ? -x : x;
-      this.block_.outputConnection.setOffsetInBlock(
+      this.block_.outputConnection?.setOffsetInBlock(
         connX,
         this.info_.outputConnection.connectionOffsetY,
       );