Merge pull request #1358 from dgageot/editor-backspace-bug

Fix one more issue with the editor

Author: dgageot

pkg/tui/components/editor/backspace_cursor_test.go

@@ -101,3 +101,55 @@ func TestBackspaceCursorPosition(t *testing.T) {
 		assert.Equal(t, "CCC", lines[2])
 	})
 }
+
+func TestBackspaceOnSoftWrappedLine(t *testing.T) {
+	t.Parallel()
+
+	t.Run("backspace after newline on soft-wrapped text", func(t *testing.T) {
+		t.Parallel()
+
+		ta := textarea.New()
+		ta.SetWidth(20) // Small width to force wrapping
+		ta.SetHeight(10)
+		ta.Focus()
+
+		e := &editor{
+			textarea:  ta,
+			userTyped: true,
+		}
+
+		// Enter text that overflows to line 2 (soft-wraps)
+		longText := "this is a long text that wraps"
+		e.textarea.SetValue(longText)
+		e.textarea.MoveToEnd()
+
+		t.Logf("After long text - Line: %d, LineInfo: %+v, Value: %q",
+			e.textarea.Line(), e.textarea.LineInfo(), e.textarea.Value())
+
+		// Press shift+enter to add a newline (simulated by directly adding \n)
+		e.textarea.InsertString("\n")
+
+		t.Logf("After newline - Line: %d, LineInfo: %+v, Value: %q",
+			e.textarea.Line(), e.textarea.LineInfo(), e.textarea.Value())
+
+		// Type a few characters
+		e.textarea.InsertString("abc")
+
+		t.Logf("After typing abc - Line: %d, LineInfo: %+v, Value: %q",
+			e.textarea.Line(), e.textarea.LineInfo(), e.textarea.Value())
+
+		// Now backspace
+		_, _ = e.handleGraphemeBackspace()
+
+		value := e.textarea.Value()
+		t.Logf("After backspace - Line: %d, LineInfo: %+v, Value: %q",
+			e.textarea.Line(), e.textarea.LineInfo(), value)
+
+		// The value should be the long text + newline + "ab"
+		expectedValue := longText + "\nab"
+		assert.Equal(t, expectedValue, value, "value should have one char removed")
+
+		// Cursor should still be on logical line 1 (the line after the newline)
+		assert.Equal(t, 1, e.textarea.Line(), "cursor should stay on line 1")
+	})
+}

pkg/tui/components/editor/editor.go

@@ -837,18 +837,40 @@ func (e *editor) handleGraphemeBackspace() (layout.Model, tea.Cmd) {
 	lines[currentLine] = newBeforeCursor + afterCursor
 	newValue := strings.Join(lines, "\n")
 
-	// Calculate new cursor position
+	// Calculate new cursor column position within the current line
 	newCol := len([]rune(newBeforeCursor))
 
-	e.textarea.SetValue(newValue)
-	// Position cursor on the correct line and column.
-	// SetValue does not reset cursor position, so we must first go to the
-	// beginning of the input, then navigate down to the target line.
-	e.textarea.MoveToBegin()
-	for range currentLine {
-		e.textarea.CursorDown()
+	// Build text before cursor position (all lines before current + new before cursor)
+	var beforeParts []string
+	for i := range currentLine {
+		beforeParts = append(beforeParts, lines[i])
+	}
+	beforeParts = append(beforeParts, newBeforeCursor)
+	textBeforeCursor := strings.Join(beforeParts, "\n")
+
+	// Build text after cursor position (after cursor on current line + remaining lines)
+	var textAfterCursor string
+	textAfterCursor = afterCursor
+	for i := currentLine + 1; i < len(lines); i++ {
+		textAfterCursor += "\n" + lines[i]
+	}
+
+	// Set the text before cursor and move to end
+	e.textarea.SetValue(textBeforeCursor)
+	e.textarea.MoveToEnd()
+
+	// Now insert the text after cursor - this positions cursor correctly
+	if textAfterCursor != "" {
+		e.textarea.SetValue(newValue)
+		e.textarea.MoveToBegin()
+
+		// Keep calling CursorDown until we're on the target logical line
+		for e.textarea.Line() < currentLine {
+			e.textarea.CursorDown()
+		}
+
+		e.textarea.SetCursorColumn(newCol)
 	}
-	e.textarea.SetCursorColumn(newCol)
 
 	e.refreshSuggestion()
 	return e, tea.Batch(textarea.Blink, e.updateCompletionQuery())