crecord: ensure that curses is False if not imported This provides no functional change but makes the next two patches easier to review.

crecord: add helper function to determine if we should use curses To fix issue5008 properly, we need a helper function to determine if curses is imported and also if the user has enabled the experimental flag.

crecord: use try/except for import of curses Not only does this improve fragility with 'if os.name == ...' it will help future patches enable the behavior to fallback to use plain record when curses is unavailable (e.g. python compiled without curses support).

histedit: only use pickle if not using the modern save format This avoids a case where PyPy's cPickle module throws a more confusing error than CPython's.

perf: close transaction in perffncachewrite This fixes a bug, and brings CPython behaviour on this test into line with PyPy.

hbisect: use tryreadlines to load state This closes the file handle after reading, which stops PyPy from leaking open file handles and thus failing test-bisect3.t.

eol: make output stable This eliminates a divergence in behaviour between PyPy and Python.

exchange: use absolute_import

localrepo: use absolute_import

httpconnection: use absolute_import