On Thu, Feb 27, 2020 at 09:09:09PM +0100, Robert Smith wrote:
> * gnu/packages/patches/anki-mpv-args.patch: New file.
> * gnu/packages/education.scm (anki): Adjust accordingly.
Please add the new file to gnu/local.mk

> @@ -779,6 +780,9 @@ adjust the level of difficulty.")
>                             (wrap-program program
>                               `("QTWEBENGINEPROCESS_PATH" =
>                                 (,qtwebengineprocess))
> +                             `("PATH" prefix (,(string-append
> +                                                (assoc-ref inputs "mpv")
> +                                                "/bin")))
>                               `("PYTHONPATH" = ,site-packages)))
>                           (find-files bin ".")))
>               #t)))))
Please mention this in the commit message.

> diff --git a/gnu/packages/patches/anki-mpv-args.patch b/gnu/packages/patches/anki-mpv-args.patch
> new file mode 100644
> index 0000000000..a66632c0e0
> --- /dev/null
> +++ b/gnu/packages/patches/anki-mpv-args.patch
> @@ -0,0 +1,30 @@
> +From 0e2c723f2b920f96937725a12e3db13c14795117 Mon Sep 17 00:00:00 2001
> +From: Robert Smith <robertsmith@posteo.net>
> +Date: Thu, 27 Feb 2020 20:07:08 +0100
> +Subject: [PATCH] Fix mpv argument formatting
> +
> +---
> +mpv now requires that the input-ipc-server argument be passed with an
> +equals sign and without any spaces.  This is a slightly out-of-date
> +version of anki, so presumably mpv used to be more lenient with
> +command line arguments.
> +---
> + anki/mpv.py | 2 +-
> + 1 file changed, 1 insertion(+), 1 deletion(-)
I don't know how I feel about this header for the patch.

> +--- a/anki/mpv.py
> ++++ b/anki/mpv.py
> +@@ -104,7 +104,7 @@ class MPVBase:
> +         """
> +         self.argv = [self.executable]
> +         self.argv += self.default_argv
> +-        self.argv += ["--input-ipc-server", self._sock_filename]
> ++        self.argv += ["--input-ipc-server=" + self._sock_filename]
> +         if self.window_id is not None:
> +             self.argv += ["--wid", str(self.window_id)]
It seems that this is not the only place that should be modified,
considering the upstream commit that fixes the same issue:
https://github.com/ankitects/anki/commit/ccd715013609133c55e83924734efa78abc03326