There is a special variable `debug-ignored-errors' with the list
of error messages to ignore, and as I see it already contains
"^No dynamic expansion for .* found$". So when debug-on-error
is non-nil, `dabbrev-expand' is not disturbing due to this variable.
Do you have a test case where `debug-ignored-errors' gets ignored?
Thanks, I forgot about that variable.
No, I can't understand what happened before right now. I get no error
now. I will try to actually read the error message next time ;-)
Ah, I now see what is wrong. When `dabbrev-check-other-buffers' is nil,
the error message is "No dynamic expansion for \"%s\" found in this-buffer"
that is not matched by `debug-ignored-errors'. The following patch
fixes this. All the rest messages are already covered by this list.