python-hglib and vimdiff

[Yuya Nishihara]

On Thu, 15 Oct 2020 13:02:12 +0000, Frankie Fisher wrote:
> We're running into some issues with hglib and I wonder if anyone has seen a similar issue before. When we trigger some merges within hglib, the library freezes (on user input) if vimdiff is the merge tool that hg selects, but operate as normal if gvimdiff or meld is selected.

In python-hglib session, hg can't access to tty, so any interactive CLI
programs wouldn't work. In perfect world, such programs will either exit
immediately or fall back to non-interactive mode, but maybe vimdiff tries
hard to obtain a tty?