Previously, even if debug-on-error was non-nil, the debugger would not
trap on part renderer errors. This made debugging part renderer bugs
frustrating, so let the debugger trap these errors.
(while (and handlers
(not (condition-case err
(funcall (car handlers) msg part content-type nth depth button)
- (error (progn
+ ;; Specifying `debug' here lets the debugger
+ ;; run if `debug-on-error' is non-nil.
+ ((debug error)
+ (progn
(insert "!!! Bodypart insert error: ")
(insert (error-message-string err))
(insert " !!!\n") nil)))))