New submission from Michael Enßlin: This issue was previously addressed and fixed here:
http://bugs.python.org/issue1351692 When subclassing PrettyPrinter, overriding the format() method should allow users to define custom pretty-printers. However, for objects whose repr is short, format() is not called for the individual members. Example code that reproduces the issue is as follows: import pprint import sys pprint.pprint(sys.version_info) class MyPrettyPrinter(pprint.PrettyPrinter): def format(self, object, context, maxlevels, level): if isinstance(object, int): return hex(object), True, False else: return pprint.PrettyPrinter.format(self, object, context, maxlevels, level) MyPrettyPrinter().pprint(10) MyPrettyPrinter().pprint([10]) When run with different versions of Python: sys.version_info(major=2, minor=7, micro=11, releaselevel='final', serial=0) 0xa [0xa] (3, 0, 1, 'final', 0) 0xa [10] sys.version_info(major=3, minor=2, micro=5, releaselevel='final', serial=0) 0xa [10] sys.version_info(major=3, minor=4, micro=4, releaselevel='final', serial=0) 0xa [10] sys.version_info(major=3, minor=6, micro=0, releaselevel='beta', serial=4) 0xa [10] You'll notice that the regression exists in all versions >= 3.0, even though the commit that fixed the issue is still in the log (2008-01-20): https://hg.python.org/cpython/log/3.0/Lib/pprint.py I have not had the time to look at the source of the issue or provide a fix; I might do so tonight. ---------- components: Library (Lib) messages: 282159 nosy: anthonybaxter, doerwalter, georg.brandl, gvanrossum, markhirota, mic_e, rhettinger priority: normal severity: normal status: open title: Regression in Python 3: Subclassing PrettyPrinter.format doesn't work anymore type: behavior versions: Python 3.3, Python 3.4, Python 3.5, Python 3.6 _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue28850> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
