matplotlib's experiences porting to Python 3.
- Easy things (that 2to3 handles pretty well):
- - print function - "in" vs. "has_key" - "except Exception as exc" syntax - stdlib stuff
- Unicode
- - Unicode literals by default - no implicit conversion between Unicode and bytes (encoding must be explicit) - files must have explicit Unicode encoding, or be binary -- hard to do both at same time
- Exceptions
exceptions_found = []
try:
do_something()
except Exception as e:
exceptions_found.append(e)Since e now has a traceback member, this creates a cycle e -> traceback -> current stack frame -> e. This cycle will keep alive all local variables in all frames beneath the source of the exception.
- C/C++ issues
- - For us, mostly hidden by using CXX
- PyCObject was dropped in Python 3.2 -- had to port CXX to use its replacement PyCapsule