fix: Drag immovable and shadow blocks along with their parent. (#9281)

Author: gonfunko

core/block.ts

@@ -501,22 +501,32 @@ export class Block {
       // Detach this block from the parent's tree.
       this.previousConnection.disconnect();
     }
-    const nextBlock = this.getNextBlock();
-    if (opt_healStack && nextBlock && !nextBlock.isShadow()) {
-      // Disconnect the next statement.
-      const nextTarget = this.nextConnection?.targetConnection ?? null;
-      nextTarget?.disconnect();
-      if (
-        previousTarget &&
-        this.workspace.connectionChecker.canConnect(
-          previousTarget,
-          nextTarget,
-          false,
-        )
-      ) {
-        // Attach the next statement to the previous statement.
-        previousTarget.connect(nextTarget!);
-      }
+
+    if (!opt_healStack) return;
+
+    // Immovable or shadow next blocks need to move along with the block; keep
+    // going until we encounter a normal block or run off the end of the stack.
+    let nextBlock = this.getNextBlock();
+    while (nextBlock && (nextBlock.isShadow() || !nextBlock.isMovable())) {
+      nextBlock = nextBlock.getNextBlock();
+    }
+    if (!nextBlock) return;
+
+    // Disconnect the next statement.
+    const nextTarget =
+      nextBlock.previousConnection?.targetBlock()?.nextConnection
+        ?.targetConnection ?? null;
+    nextTarget?.disconnect();
+    if (
+      previousTarget &&
+      this.workspace.connectionChecker.canConnect(
+        previousTarget,
+        nextTarget,
+        false,
+      )
+    ) {
+      // Attach the next statement to the previous statement.
+      previousTarget.connect(nextTarget!);
     }
   }
 

tests/mocha/block_test.js

@@ -201,6 +201,35 @@ suite('Blocks', function () {
 
         assertUnpluggedHealFailed(blocks);
       });
+      test('Disconnect top of stack with immovable sibling', function () {
+        this.blocks.B.setMovable(false);
+        this.blocks.A.unplug(true);
+        assert.equal(this.blocks.A.nextConnection.targetBlock(), this.blocks.B);
+        assert.isNull(this.blocks.B.nextConnection.targetBlock());
+        assert.isNull(this.blocks.C.previousConnection.targetBlock());
+      });
+      test('Heal with immovable sibling mid-stack', function () {
+        const blockD = this.workspace.newBlock('stack_block', 'd');
+        this.blocks.C.nextConnection.connect(blockD.previousConnection);
+        this.blocks.C.setMovable(false);
+        this.blocks.B.unplug(true);
+        assert.equal(this.blocks.A.nextConnection.targetBlock(), blockD);
+        assert.equal(this.blocks.B.nextConnection.targetBlock(), this.blocks.C);
+        assert.isNull(this.blocks.C.nextConnection.targetBlock());
+      });
+      test('Heal with immovable sibling and shadow sibling mid-stack', function () {
+        const blockD = this.workspace.newBlock('stack_block', 'd');
+        const blockE = this.workspace.newBlock('stack_block', 'e');
+        this.blocks.C.nextConnection.connect(blockD.previousConnection);
+        blockD.nextConnection.connect(blockE.previousConnection);
+        this.blocks.C.setMovable(false);
+        blockD.setShadow(true);
+        this.blocks.B.unplug(true);
+        assert.equal(this.blocks.A.nextConnection.targetBlock(), blockE);
+        assert.equal(this.blocks.B.nextConnection.targetBlock(), this.blocks.C);
+        assert.equal(this.blocks.C.nextConnection.targetBlock(), blockD);
+        assert.isNull(blockD.nextConnection.targetBlock());
+      });
       test('Child is shadow', function () {
         const blocks = this.blocks;
         blocks.C.setShadow(true);