Less -w prints carriage return ^M in blank lines

[imbrish]

I have noticed a potential bug in less.

When viewing files with windows line endings (CRLF), less -w shows carriage return ^M in blank lines. Lines which are not empty display correctly, skipping the carriage returns. Without the -w option the ^M are omitted in blank lines too.

The same happens for -W. Adding -r removes the markers but is a rather unacceptable workaround.

$ printf 'A\r\n\r\nB\r\n' | LESS= less -F
A

B

$ printf 'A\r\n\r\nB\r\n' | LESS= less -Fw
A
^M
B

$ printf 'A\r\n\r\nB\r\n' | LESS= less -Fwr
A

B

When text is long enough to scroll down and then back up, the ^M disappear. So, these are only shown in the newly printed lines.

$ for ((i=0; i<40; i++)); do printf 'A\r\n\r\nB\r\n'; done | LESS= less -w
(lines scrolled back to)
A

B
(freshly printed lines)
A
^M
B

Tested with git 2.43.0.windows.1, bash 5.2.21(1), less 643.

[gwsw]

Note: this bug was introduced in 1aad5cb.

[gwsw]

Fixed in 94f1ae3.