fix: don't collapse emptied columns when moving blocks

Moves are rearrangements rather than deletions, so columns that a move
empties out are deliberately left as-is instead of being collapsed. This
keeps moves free of side effects (and reversible by moving back), matches
dragging a block out of a column, and fixes the original error: collapsing
a transiently-empty column mid-move broke the re-insertion.

Also simplifies `removeAndInsertBlocks` (plain `fixColumns` opt-out, no
`affectedColumnLists` return) and removes the columnList reference
anchoring workaround in `moveBlocks`, which guarded against mid-move
collapsing that can no longer happen.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Author: YousefED

packages/core/src/api/blockManipulation/commands/moveBlocks/moveBlocks.ts

@@ -13,7 +13,6 @@ import { getNearestBlockPos } from "../../../getBlockInfoFromPos.js";
 import { getNodeById } from "../../../nodeUtil.js";
 import { insertBlocks } from "../insertBlocks/insertBlocks.js";
 import { removeAndInsertBlocks } from "../replaceBlocks/replaceBlocks.js";
-import { fixColumnList } from "../replaceBlocks/util/fixColumnList.js";
 
 type BlockSelectionData = (
   | {
@@ -152,40 +151,20 @@ export function moveBlocks(
   placement: "before" | "after",
 ) {
   editor.transact((tr) => {
-    // A `columnList` reference can be dissolved by `fixColumnList` when its
-    // `column`s are removed, leaving its ID invalid for re-insertion. Anchor
-    // to an adjacent block instead, which is unaffected by the removal.
-    const refBlock = editor.getBlock(referenceBlock);
-    if (refBlock?.type === "columnList") {
-      const adjacent =
-        placement === "after"
-          ? editor.getNextBlock(refBlock)
-          : editor.getPrevBlock(refBlock);
-      if (adjacent) {
-        referenceBlock = adjacent;
-        placement = placement === "after" ? "before" : "after";
-      }
-    }
-
-    // Don't fix columns/columnLists in the removal step. Otherwise, the
-    // following case breaks:
+    // Don't fix columns/columnLists in the removal step. Since a move is a
+    // rearrangement rather than a deletion, columns that it empties out are
+    // deliberately left as-is instead of being collapsed - this keeps moves
+    // free of side effects (and reversible by moving back), and matches
+    // dragging a block out of a column, which doesn't collapse it either.
+    // Fixing them mid-move also broke the following case:
     // <column>
     //  <paragraph></paragraph>
     //  <paragraph>Paragraph</paragraph>
     // </column>
-    // When the non-empty block is moved up, the column is now seen as empty
-    // and collapsed in the removal step, so the following insertion fails.
-    const { affectedColumnLists } = removeAndInsertBlocks(tr, blocks, [], {
-      fixColumns: false,
-    });
+    // When the non-empty block is moved up, the column is seen as empty and
+    // collapsed in the removal step, so the following insertion fails.
+    removeAndInsertBlocks(tr, blocks, [], { fixColumns: false });
     insertBlocks(tr, flattenColumns(blocks), referenceBlock, placement);
-
-    affectedColumnLists.forEach((id) => {
-      const posInfo = getNodeById(id, tr.doc);
-      if (posInfo) {
-        fixColumnList(tr, posInfo.posBeforeNode);
-      }
-    });
   });
 }
 

packages/core/src/api/blockManipulation/commands/replaceBlocks/replaceBlocks.ts

@@ -26,7 +26,6 @@ export function removeAndInsertBlocks<
 ): {
   insertedBlocks: Block<BSchema, I, S>[];
   removedBlocks: Block<BSchema, I, S>[];
-  affectedColumnLists: string[];
 } {
   const pmSchema = getPmSchema(tr);
   // Converts the `PartialBlock`s to ProseMirror nodes to insert them into the
@@ -116,17 +115,9 @@ export function removeAndInsertBlocks<
     );
   }
 
-  // Saves IDs of columnLists containing removed blocks. If `fixColumns` is
-  // explicitly false, these are needed to run `fixColumnList` manually later.
-  const affectedColumnLists: string[] = [];
-  columnListPositions.forEach((pos) => {
-    const columnList = tr.doc.resolve(pos).nodeAfter;
-    if (columnList?.type.name === "columnList") {
-      affectedColumnLists.push(columnList.attrs.id);
-    }
-  });
-
-  // Collapses empty columns/columnLists
+  // Collapses empty columns/columnLists. Callers where the removal isn't a
+  // deletion can opt out - e.g. `moveBlocks` re-inserts the blocks elsewhere
+  // and deliberately leaves emptied columns as-is.
   if (options.fixColumns !== false) {
     columnListPositions.forEach((pos) => fixColumnList(tr, pos));
   }
@@ -136,5 +127,5 @@ export function removeAndInsertBlocks<
     nodeToBlock(node, pmSchema),
   ) as Block<BSchema, I, S>[];
 
-  return { insertedBlocks, removedBlocks, affectedColumnLists };
+  return { insertedBlocks, removedBlocks };
 }