Don't recommend deprecated `xvfb-run -a`

[micheljung]

-a is deprecated:

-a        --auto-servernum          try to get a free server number, starting at
                                    --server-num (deprecated, use --auto-display
                                    instead)
-d        --auto-display            use the X server to find a display number
                                    automatically

and can cause problems. See https://github.com/plotly/orca/issues/239#issuecomment-561553654

[antoinerg]

Thank you @micheljung for reporting this. It does seem like -a is deprecated in recent version of xvfb-run but it hasn't made its way into Ubuntu. Even in version 20.04 I get:

xvfb-run: usage error: need a command to run

Usage: xvfb-run [OPTION ...] COMMAND
Run COMMAND (usually an X client) in a virtual X server environment.
Options:
-a        --auto-servernum          try to get a free server number, starting at
                                    --server-num
-e FILE   --error-file=FILE         file used to store xauth errors and Xvfb
                                    output (default: /dev/null)
-f FILE   --auth-file=FILE          file used to store auth cookie
                                    (default: ./.Xauthority)
-h        --help                    display this usage message and exit
-n NUM    --server-num=NUM          server number to use (default: 99)
-l        --listen-tcp              enable TCP port listening in the X server
-p PROTO  --xauth-protocol=PROTO    X authority protocol name to use
                                    (default: xauth command's default)
-s ARGS   --server-args=ARGS        arguments (other than server number and
                                    "-nolisten tcp") to pass to the Xvfb server
                                    (default: "-screen 0 1280x1024x24")

I'm curious to know whether you installed xvfb-run via your distro's package manger? If so, what distro/version are you using?

[micheljung]

After xvfb-run --version didn't exist I gave up looking for its version :) We're on RHEL7. I'll try to gather some more info tomorrow.

[antoinerg]

We're on RHEL7. I'll try to gather some more info tomorrow.

Good to know :) I am also using a more recent version like you are.

After xvfb-run --version didn't exist I gave up looking for its version :)

I understand! It's a weird omission on their part. It looks like xvfb-run is a one file project. Here's how it's packaged in NixOS.

Anyway, in your PR just mention -d is recommended on newer versions. I would keep mentioning -a for all the Ubuntu users out there who may not get updated for a while.

Thanks again @micheljung

[tjaalton]

note that xvfb-run was forked from Debian in 2008, and this '-d' thing was added in the Fedora fork 4y ago...