Error message "Invalid MIT-MAGIC-COOKIE-1 key" not followed by a newline character
After the X server has shut down, I get:
$ DISPLAY=:0 xterm Invalid MIT-MAGIC-COOKIE-1 key/usr/bin/xterm: Xt error: Can't open display: :0
The error message "Invalid MIT-MAGIC-COOKIE-1 key" is not followed by a newline character; this breaks parsing of the output (I initially got this error in a
make check). Ditto with other applications linked against libX11 (so that I suppose that this is the culprit).
Moreover, the error message should be preceded by the library name, otherwise one needs to guess where it comes from.
I also reported the bug in the Debian BTS: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=914949