Sometimes a problem with a function is due to a wrong setting of a variable. Setting up the debugger to trigger whenever the variable is changed is a quick way to find the origin of the setting.
debug-on-variable-change
variable ¶This function arranges for the debugger to be called whenever variable is modified.
It is implemented using the watchpoint mechanism, so it inherits the same characteristics and limitations: all aliases of variable will be watched together, only dynamic variables can be watched, and changes to the objects referenced by variables are not detected. For details, see Running a function when a variable is changed..
cancel-debug-on-variable-change
&optional variable ¶This function undoes the effect of debug-on-variable-change
on
variable. When called interactively, it prompts for
variable in the minibuffer. If variable is omitted or
nil
, it cancels break-on-change for all variables. Calling
cancel-debug-on-variable-change
does nothing to a variable
which is not currently set up to break on change.