Commit 43882ade authored by Committed by GitHub
Fix substraction underflow with IL sequence
The IL escape sequence (CSI Ps L) allows inserting blank, uninitialized lines. `Ps` is a placeholder for the number of lines that should be inserted. Before this change Alacritty would crash when a large number of lines was passed as `Ps` parameter. The issue was caused whenever the current line of the cursor plus the lines that should be inserted would leave the bottom of the terminal, since this makes indexing impossible. This patch makes sure that the biggest amount of lines inserted does never exceed the end of the visible region minus the current line of the curser, which fixes the underflow issue. This fixes #1515.
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