profile: properly propagate exception from the sub-context manager Context manager has a mechanism to control extension propagation. It is not used by profiling right now, but making the code correct will help prevent bug in the future.

profile: close 'fp' in all cases There are no way for this to happen today, but better be safe than sorry, no one know how the code will evolve. We now make sure the file pointer is closed even is profiler is None.

profile: close 'fp' on error within '__enter__' Previously, error when initialying the profiler would forgot to explicitly close the file. Thank goes to Yuya Nishihara for spotting this.

profile: indent part of '__enter__' We are about to introduce a try except. We start with adding the indent to make the next patch clearer.

profile: remove now useless indent We no longer rely on the value of '_output' so we can remove this conditional.

profile: use explicit logic to control file closing We make the decision to close 'fp' more explicit instead of relying on the implication of other variable. This makes the overall logic more robust.