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Differential D5426

error: implement __str__ on RevlogError to fix some output defects on Py3
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Authored by durin42 on Dec 14 2018, 12:14 PM.

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pulkit
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rHGf732889abe0e: error: implement __str__ on RevlogError to fix some output defects on Py3
rHG248c53e169a0: error: implement __str__ on RevlogError to fix some output defects on Py3
Summary

We open-code encoding.unimethod here to avoid cycles, and do a local
import of encoding when someone str()s a RevlogError. It's not my
favorite solution, but it gets the job done.

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Event Timeline

durin42 created this revision.Dec 14 2018, 12:14 PM
pulkit accepted this revision.Dec 14 2018, 12:21 PM
Closed by commit rHG248c53e169a0: error: implement __str__ on RevlogError to fix some output defects on Py3 (authored by durin42). · Explain WhyDec 14 2018, 12:30 PM
This revision was automatically updated to reflect the committed changes.
yuja added a subscriber: yuja.Dec 14 2018, 8:10 PM

class RevlogError(StorageError):

__bytes__ = _tobytes

+ def str(self):
+ # avoid cycle, and directly implement unimethod for this
+ # str to allow delaying the import of encoding until
+ # someone actually wants the str of a RevlogError (which
+ # should be very rare).
+ from . import encoding
+ return encoding.unifromlocal(_tobytes(self))

It breaks str(err) on Python 2 because str shouldn't return a unicode
containing non-ASCII characters.

Suppose we just want to get rid of b''s on Python 3, we can add a helper
function like this:

if pycompat.ispy3:
    def _tostr(exc):
        return pycompat.sysstr(_tobytes(exc))
else:
    _tostr = Exception.__str__

It's safer than using encoding.unifromlocal() in that no other exception
will be raised on encoding error.

Revision Contents
Changeset List

PathPackages
Mmercurial/error.py (8 lines)

Diff 12851

mercurial/error.py

Usually subclassed by a storage-specific exception. Usually subclassed by a storage-specific exception.
""" """
__bytes__ = _tobytes __bytes__ = _tobytes
class RevlogError(StorageError): class RevlogError(StorageError):
__bytes__ = _tobytes __bytes__ = _tobytes
def __str__(self):
# avoid cycle, and directly implement unimethod for this
# __str__ to allow delaying the import of encoding until
# someone actually wants the __str__ of a RevlogError (which
# should be very rare).
from . import encoding
return encoding.unifromlocal(_tobytes(self))
class FilteredIndexError(IndexError): class FilteredIndexError(IndexError):
__bytes__ = _tobytes __bytes__ = _tobytes
class LookupError(RevlogError, KeyError): class LookupError(RevlogError, KeyError):
def __init__(self, name, index, message): def __init__(self, name, index, message):
self.name = name self.name = name
self.index = index self.index = index
# this can't be called 'message' because at least some installs of # this can't be called 'message' because at least some installs of