regression in 1.13.0-beta1: incorrect region highlighting in the REPL #60762
Description
Write some text in the REPL, go back to the middle of the text and then press Shift-Right. In Julia 1.12, each Shift-Right would add one character to the text displayed in reverse (initially just the character where the cursor is). In Julia 1.13.0-beta1 and master, the first Shift-Right also reverses the character to the left of the cursor position. It stays inverted on subsequent Shift-Right. In the following picture, the cursor was at "m" when I started pressing Shift-Right:
The first time one presses Shift-Left in 1.12, the character underneath the cursor changes from reverse to normal display, so that no character at all is in reverse. Subsequent Shift-Left invert the characters to the left of the original cursor position. In Julia 1.13 and master, the first Shift-Left moves the character displayed in reverse two positions to the left. Afterwards the inverted region grows, but there will always be one character (the one to the right of the first inverted character) that is not displayed in reverse. In the following picture, the cursor was again at "m" when I started pressing Shift-Left:
In all, this looks like a classical off-by-one error.
Tested with xterm 372 and rxvt-unicode 9.22.