fix: resolve "Bad state: no element" when in-table paragraph deleted (#471)

Author: sun-jiao

lib/src/editor/editor_component/service/shortcuts/command_shortcut_events/backspace_command.dart

@@ -67,23 +67,33 @@ CommandShortcutEventHandler _backspaceInCollapsedSelection = (editorState) {
           ),
         );
     } else {
-      // merge with the previous node contains delta.
-      final previousNodeWithDelta =
-          node.previousNodeWhere((element) => element.delta != null);
-      if (previousNodeWithDelta != null) {
-        assert(previousNodeWithDelta.delta != null);
+      Node? tableParent =
+          node.findParent((element) => element.type == TableBlockKeys.type);
+      Node? prevTableParent;
+      final prev = node.previousNodeWhere((element) {
+        prevTableParent = element
+            .findParent((element) => element.type == TableBlockKeys.type);
+        // break if only one is in a table or they're in different tables
+        return tableParent != prevTableParent ||
+            // merge with the previous node contains delta.
+            element.delta != null;
+      });
+      // table nodes should be deleted using the table menu
+      // in-table paragraphs should only be deleted inside the table
+      if (prev != null && tableParent == prevTableParent) {
+        assert(prev.delta != null);
         transaction
-          ..mergeText(previousNodeWithDelta, node)
+          ..mergeText(prev, node)
           ..insertNodes(
             // insert children to previous node
-            previousNodeWithDelta.path.next,
+            prev.path.next,
             node.children.toList(),
           )
           ..deleteNode(node)
           ..afterSelection = Selection.collapsed(
             Position(
-              path: previousNodeWithDelta.path,
-              offset: previousNodeWithDelta.delta!.length,
+              path: prev.path,
+              offset: prev.delta!.length,
             ),
           );
       } else {

lib/src/editor/editor_component/service/shortcuts/command_shortcut_events/delete_command.dart

@@ -44,10 +44,21 @@ CommandShortcutEventHandler _deleteInCollapsedSelection = (editorState) {
 
   final transaction = editorState.transaction;
 
-  // merge the next node with delta
   if (position.offset == delta.length) {
-    final next = node.findDownward((element) => element.delta != null);
-    if (next != null) {
+    Node? tableParent =
+        node.findParent((element) => element.type == TableBlockKeys.type);
+    Node? nextTableParent;
+    final next = node.findDownward((element) {
+      nextTableParent =
+          element.findParent((element) => element.type == TableBlockKeys.type);
+      // break if only one is in a table or they're in different tables
+      return tableParent != nextTableParent ||
+          // merge the next node with delta
+          element.delta != null;
+    });
+    // table nodes should be deleted using the table menu
+    // in-table paragraphs should only be deleted inside the table
+    if (next != null && tableParent == nextTableParent) {
       if (next.children.isNotEmpty) {
         final path = node.path + [node.children.length];
         transaction.insertNodes(path, next.children);

lib/src/extensions/node_extensions.dart

@@ -132,6 +132,14 @@ extension NodeExtensions on Node {
     }
     return false;
   }
+
+  Node? findParent(bool Function(Node element) test) {
+    if (test(this)) {
+      return this;
+    }
+    final parent = this.parent;
+    return parent?.findParent(test);
+  }
 }
 
 extension NodesExtensions<T extends Node> on List<T> {