xolox#shell#highlight_urls() seems to slow down Vim

[gpakosz]

Hello,

I can't pinpoint when it started to happen but it seems xolox#shell#highlight_urls() is slowing down Vim.

Vim would hang for a while and more often than not disable syntax highlighting because redraw time its the timemout.

When it happens and I press CTRL+C, I get:

Error detected while processing function xolox#shell#highlight_urls:
line   14:
E409: Unknown group name: .*String.*
E475: Invalid argument: CommentEmail /\<\w[^@ \t\r<>]*\w@\w[^@ \t\r<>]\+\w\>/ contained containedin=.*Comment.*,.*String.*
Interrupt: Press ENTER or type command to continue

I'm using

VIM - Vi IMproved 8.2 (2019 Dec 12, compiled Mar  4 2020 22:40:59)
macOS version
Included patches: 1-350
Compiled by Homebrew

And c19945c