When an Xnest instance is not viewable it will crash when a client in
that instance calls GetImage. This is because the Xnest server will
itself receives a BadMatch error.
This patch ignores the error. The application which has requested the
image will receive garbage - this however is fully legal according
to the specs as obscured areas will always contain garbage if there
isn't some sort of backing store as discussed in
https://bugs.freedesktop.org/show_bug.cgi?id=9488
The applied patch is a version from Dadek Doulik.
v2: Call XSync() before changing error handlers as suggested by
Daniel Stone <daniel@fooishbar.org>.
Reviewed-by: Daniel Stone <daniel@fooishbar.org>
Signed-off-by: Egbert Eich <eich@freedesktop.org>
65fca55884