bug#30019: 26.0.90; Invalid specification of parent-frame with desktop-read

[martin rudalics <rudalics@gmx.at>]

 >> When you put a breakpoint at the last line I suppose it's the
 >> FRAME_X_P (p) call that failed. Can you confirm that?
 >
 > Confirmed, it was FRAME_X_P (p) that came back false.

In practice this means that with desktop in use I have to install some
sort of hook or timer that triggers when the parent frame has been
mapped and reparent the (until then probably hidden and not yet
parented) child frame.  This is not entirely trivial and is not suited
for the release branch.  Meanwhile could you try putting a
`condition-case-unless-debug' around the two

(set-frame-parameter frame 'parent-frame parent-frame)

calls in frameset.el and tell me whether restoring the other frames
completes normally then?

Thanks, martin