Fix/issue 2593 cursor resets to end of paragraph after paste

super_editor/lib/src/default_editor/common_editor_operations.dart

@@ -100,7 +100,8 @@ class CommonEditorOperations {
   }) {
     DocumentPosition? position;
     if (findNearestPosition) {
-      position = documentLayoutResolver().getDocumentPositionNearestToOffset(documentOffset);
+      position = documentLayoutResolver()
+          .getDocumentPositionNearestToOffset(documentOffset);
     } else {
       position = documentLayoutResolver().getDocumentPositionAtOffset(documentOffset);
     }
@@ -2510,17 +2511,31 @@ class PasteEditorCommand extends EditCommand {
       ]);
     }
 
-    // Place the caret at the end of the pasted content.
-    final pastedNode = document.getNodeById(previousNode.id)!;
-    // ^ re-query the node where we pasted content because nodes are immutable.
-
+    late DocumentPosition documentPositionAfterPaste;
+    if (parsedContent.length > 1) {
+      // Place the caret at the end of the pasted content.
+      final pastedNode = document.getNodeById(previousNode.id)!;
+      // ^ re-query the node where we pasted content because nodes are immutable.
+      documentPositionAfterPaste = DocumentPosition(
+        nodeId: pastedNode.id,
+        nodePosition: pastedNode.endPosition,
+      );
+    } else {
+      // The user only pasted content without any newlines in it. Place the
+      // caret in the existing node at the end of the pasted text. This is
+      // guaranteed to be a TextNode.
+      documentPositionAfterPaste = DocumentPosition(
+        nodeId: _pastePosition.nodeId,
+        nodePosition: TextNodePosition(
+          offset:
+              pasteTextOffset + (_parsedContent!.first as TextNode).text.length,
+        ),
+      );
+    }
     executor.executeCommand(
       ChangeSelectionCommand(
         DocumentSelection.collapsed(
-          position: DocumentPosition(
-            nodeId: pastedNode.id,
-            nodePosition: pastedNode.endPosition,
-          ),
+          position: documentPositionAfterPaste,
         ),
         SelectionChangeType.insertContent,
         SelectionReason.userInteraction,

super_editor/test/super_editor/supereditor_copy_and_paste_test.dart

@@ -7,6 +7,7 @@ import 'package:super_editor/super_editor.dart';
 import 'package:super_editor/super_editor_test.dart';
 
 import '../test_runners.dart';
+import '../test_tools.dart';
 import 'supereditor_test_tools.dart';
 
 void main() {
@@ -36,6 +37,56 @@ void main() {
       expect(SuperEditorInspector.findTextInComponent(nodeId).toPlainText(), "Pasted text: This was pasted here");
     });
 
+    testAllInputsOnDesktop(
+        'pastes some text in the middle of a paragraph, correctly placing the caret at the end of the pasted text',
+        (
+      tester, {
+      required TextInputSource inputSource,
+    }) async {
+      final testContext = await tester //
+          .createDocument()
+          .withSingleEmptyParagraph()
+          .withInputSource(inputSource)
+          .pump();
+
+      // Place the caret at the empty paragraph.
+      await tester.placeCaretInParagraph('1', 0);
+
+      // Type some text.
+      switch (inputSource) {
+        case TextInputSource.keyboard:
+          await tester.typeKeyboardText('This is a paragraph');
+        case TextInputSource.ime:
+          await tester.typeImeText('This is a paragraph');
+      }
+
+      // Place the cursor somewhere in the middle of the text.
+      await tester.placeCaretInParagraph('1', 8);
+
+      // Simulate pasting multiple lines.
+      tester
+        ..simulateClipboard()
+        ..setSimulatedClipboardContent('some content in ');
+      if (defaultTargetPlatform == TargetPlatform.macOS) {
+        await tester.pressCmdV();
+      } else {
+        await tester.pressCtlV();
+      }
+
+      // Ensure the text is correctly pasted and the caret is placed at the
+      // end of the pasted text.
+      final doc = testContext.document;
+      expect(doc.nodeCount, 1);
+      expect((doc.getNodeAt(0)! as ParagraphNode).text.toPlainText(), 'This is some content in a paragraph');
+      expect(testContext.composer.selection, selectionEquivalentTo(const DocumentSelection.collapsed(
+        position: DocumentPosition(
+          nodeId: '1',
+          nodePosition: TextNodePosition(offset: 24),
+        ),
+      )));
+    });
+
+
     testWidgetsOnApple('pastes within a list item', (tester) async {
       await tester //
           .createDocument()