Fix Backspace deleting entire previous line in <textarea> (#36112)

* test(textinput): Add test for backspace at beginning of line in textarea

Introduce a test to reproduce and verify the fix for backspacing at the
beginning of a line in a multiline textarea. This ensures that pressing
Backspace when the cursor is at the start of a line correctly removes the
newline without deleting the entire previous line’s content.

Related to: #27523

Signed-off-by: Emmanuel Elom <elomemmanuel007@gmail.com>

* fix(textinput): Preserve selection origin when adjusting vertical position

Fixes an issue where pressing Backspace at the beginning of a line in a
textarea incorrectly deleted the entire previous line's content. This happened
because `self.adjust_vertical(-1, select)` modified `selection_origin` and
`edit_point`, but `selection_origin` was not restored before performing the
horizontal adjustment. As a result, `self.selection_start()` and
`self.selection_end()` were inconsistent, leading to `replace_operation`
erasing the entire line.

Now, we temporarily store `selection_origin` before adjusting vertical
position and restore it afterward to ensure proper cursor and selection
behavior.

Fixes: #27523
Signed-off-by: Emmanuel Elom <elomemmanuel007@gmail.com>

---------

Signed-off-by: Emmanuel Elom <elomemmanuel007@gmail.com>
Co-authored-by: Josh Matthews <josh@joshmatthews.net>
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elomscansio 2025-03-26 19:37:48 +01:00 committed by GitHub
parent 4f33f31c86
commit 30a2a89d16
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@ -856,3 +856,11 @@ fn test_select_all() {
textinput.selection_end()
);
}
#[test]
fn test_backspace_in_textarea_at_beginning_of_line() {
let mut textinput = text_input(Lines::Multiple, "first line\n");
textinput.handle_keydown_aux(Key::ArrowDown, Modifiers::empty(), false);
textinput.handle_keydown_aux(Key::Backspace, Modifiers::empty(), false);
assert_eq!(textinput.get_content(), DOMString::from("first line"));
}