Newlines gets eaten on right margin on window resize if preceeded by an escape code

[kar1]

Describe the bug

This issue is a corner case on issue #971 - text wrap on resize. I was unsure if I should necromance the old closed issue.

If I cat a file to the terminal containing lines equal to the term column width, and then grow the terminal window, the lines equal to the former width will be concatenated with the next line.

The #971 bug still persist if the glyphs are enclosed in special escape codes like:
The #971 bug still persist if there is a escape code before the newline. This often happens with the folowing escape sequences:

DEC Special Graphics character set
␛(0 - Start DEC special graphics set
␛(B - Start ASCII, i.e. end DEC special graphics

DEC CSI DECTCEM
␛[?25l - Hides the cursor
␛[?25h - Shows the cursor

DEC Reset
␛0m - Resets cell attributes

DEC Special Graphics character set is often used to draw tables and boxes.
DEC CSI DECTCEM is often used to enclose ansi-art.

There may be other cases like these, but these are the ones that hit me. Let me know if I should test for more cases.

Environment (please complete the following information):

• OS: Linux X11
• Version: wezterm 20210722-094608-dcbbda77
• The active keyboard layout name: DA

To Reproduce

1. Make a file containing the escape codes:

echo -e "\e(0qqqq\e(B\nSS" > test-rsmacs.txt
echo -e "\e[?25l====\e[?25h\nSS" > test-dectcem.txt

2. Resize the terminal window to 4 columns and cat the files

cat test-rmacs.txt
cat test-dectcem.txt

3. Resize the terminal window to >6 columns and observe the lines "────SS" and "====SS".

Test cases

#[test]
fn test_resize_wrap_SGC_issue_978() {
    const LINES: usize = 4;
    let mut term = TestTerm::new(LINES, 4, 0);
    term.print("\u{1b}(0qqqq\u{1b}(B\nSS\n");
    assert_visible_contents(&term, file!(), line!(), &["────", "SS", "", ""]);
    term.resize(LINES, 6, 0, 0);
    assert_visible_contents(&term, file!(), line!(), &["────", "SS", "", ""]);
}

#[test]
fn test_resize_wrap_DECTCM_issue_978() {
    const LINES: usize = 4;
    let mut term = TestTerm::new(LINES, 4, 0);
    term.print("\u{1b}[?25l====\u{1b}[?25h\nSS\n");
    assert_visible_contents(&term, file!(), line!(), &["====", "SS", "", ""]);
    term.resize(LINES, 6, 0, 0);
    assert_visible_contents(&term, file!(), line!(), &["====", "SS", "", ""]);
}

#[test]
fn test_resize_wrap_escape_code_issue_978() {
    const LINES: usize = 4;
    let mut term = TestTerm::new(LINES, 4, 0);
    term.print("====\u{1b}0m\nSS\n");
    assert_visible_contents(&term, file!(), line!(), &["====", "SS", "", ""]);
    term.resize(LINES, 6, 0, 0);
    assert_visible_contents(&term, file!(), line!(), &["====", "SS", "", ""]);
}

Configuration

Default config

Expected behavior

Newlines on margin right edge be preserved on terminal resize even when they are enclosed in special escape codes like hide cursor (DECTCEM) and box drawing mode (DEC Special Graphics character set: smacs, rmacs)
Newlines on margin right edge be preserved on terminal resize even when there is an escape code before the newline.

[kar1]

It seems to be an issue if the there is an escape sequence before the newline

#[test]
fn test_resize_wrap_escape_code_issue_978() {
    const LINES: usize = 4;
    let mut term = TestTerm::new(LINES, 4, 0);
    term.print("====\u{1b}0m\nSS\n");
    assert_visible_contents(&term, file!(), line!(), &["====", "SS", "", ""]);
    term.resize(LINES, 6, 0, 0);
    assert_visible_contents(&term, file!(), line!(), &["====", "SS", "", ""]);
}

I think my original report was incorrect. It's not when the text is enclosed in special escape codes, but if there is an escape code before the newline.

I have edited the wording on the issue above.

[kar1]

This fixes it. Thank you for your hard work.

[github-actions]

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