Current pdb and bdb didn't have the ability to create a watchpoint for variable.
Such in gdb, it have a series of watchpoint function*:
* watch : break when expression value changed * rwatch : break when read value from expression * awatch: breka when read or write value to expression
In Python, there have some problem in rwatch implement, that we can't directly know what variable is been read or not. This will need to used the dis module to get the bytecode and to know if the variable is been read (load) or not.
The b.p.o issue is open at here: http://bugs.python.org/issue30429
And the current implement is at: https://github.com/python/cpython/pull/1756
How do you think about this ability to put in pdb/bdb?