Mercurial > hg
view hgext/win32text.py @ 33807:b70029f355a3
tests: verify that peer instances only expose interface members
Our abstract interfaces are more useful if we guarantee that
implementations conform to certain rules. Namely, we want to ensure
that objects implementing interfaces don't expose new public
attributes that aren't part of the interface. That way, as long as
consumers don't access "internal" attributes (those beginning with
"_") then (in theory) objects implementing interfaces can be swapped
out and everything will "just work."
We add a test that enforces our "no public attributes not part
of the abstract interface" rule.
We /could/ implement "interface compliance detection" at run-time.
However, that is littered with problems.
The obvious solutions are custom __new__ and __init__ methods.
These rely on derived types actually calling the parent's
implementation, which is no sure bet. Furthermore, __new__ and
__init__ will likely be called before instance-specific attributes
are assigned. In other words, they won't detect public attributes
set on self.__dict__. This means public attribute detection won't
be robust.
We could work around lack of robust self.__dict__ public attribute
detection by having our interfaces implement a custom __getattribute__,
__getattr__, and/or __setattr__. However, this incurs an undesirable
run-time penalty. And, subclasses could override our custom
method, bypassing the check.
The most robust solution is a non-runtime test. So that's what this
commit implements. We have a generic function for validating that an
object only has public attributes defined by abstract classes. Then,
we instantiate some peers and verify a newly constructed object
plays by the rules.
Differential Revision: https://phab.mercurial-scm.org/D339
author | Gregory Szorc <gregory.szorc@gmail.com> |
---|---|
date | Thu, 10 Aug 2017 21:00:30 -0700 |
parents | ec7831675867 |
children | f84358f75978 |
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# win32text.py - LF <-> CRLF/CR translation utilities for Windows/Mac users # # Copyright 2005, 2007-2009 Matt Mackall <mpm@selenic.com> and others # # This software may be used and distributed according to the terms of the # GNU General Public License version 2 or any later version. '''perform automatic newline conversion (DEPRECATED) Deprecation: The win32text extension requires each user to configure the extension again and again for each clone since the configuration is not copied when cloning. We have therefore made the ``eol`` as an alternative. The ``eol`` uses a version controlled file for its configuration and each clone will therefore use the right settings from the start. To perform automatic newline conversion, use:: [extensions] win32text = [encode] ** = cleverencode: # or ** = macencode: [decode] ** = cleverdecode: # or ** = macdecode: If not doing conversion, to make sure you do not commit CRLF/CR by accident:: [hooks] pretxncommit.crlf = python:hgext.win32text.forbidcrlf # or pretxncommit.cr = python:hgext.win32text.forbidcr To do the same check on a server to prevent CRLF/CR from being pushed or pulled:: [hooks] pretxnchangegroup.crlf = python:hgext.win32text.forbidcrlf # or pretxnchangegroup.cr = python:hgext.win32text.forbidcr ''' from __future__ import absolute_import import re from mercurial.i18n import _ from mercurial.node import ( short, ) from mercurial import ( util, ) # Note for extension authors: ONLY specify testedwith = 'ships-with-hg-core' for # extensions which SHIP WITH MERCURIAL. Non-mainline extensions should # be specifying the version(s) of Mercurial they are tested with, or # leave the attribute unspecified. testedwith = 'ships-with-hg-core' # regexp for single LF without CR preceding. re_single_lf = re.compile('(^|[^\r])\n', re.MULTILINE) newlinestr = {'\r\n': 'CRLF', '\r': 'CR'} filterstr = {'\r\n': 'clever', '\r': 'mac'} def checknewline(s, newline, ui=None, repo=None, filename=None): # warn if already has 'newline' in repository. # it might cause unexpected eol conversion. # see issue 302: # https://bz.mercurial-scm.org/302 if newline in s and ui and filename and repo: ui.warn(_('WARNING: %s already has %s line endings\n' 'and does not need EOL conversion by the win32text plugin.\n' 'Before your next commit, please reconsider your ' 'encode/decode settings in \nMercurial.ini or %s.\n') % (filename, newlinestr[newline], repo.vfs.join('hgrc'))) def dumbdecode(s, cmd, **kwargs): checknewline(s, '\r\n', **kwargs) # replace single LF to CRLF return re_single_lf.sub('\\1\r\n', s) def dumbencode(s, cmd): return s.replace('\r\n', '\n') def macdumbdecode(s, cmd, **kwargs): checknewline(s, '\r', **kwargs) return s.replace('\n', '\r') def macdumbencode(s, cmd): return s.replace('\r', '\n') def cleverdecode(s, cmd, **kwargs): if not util.binary(s): return dumbdecode(s, cmd, **kwargs) return s def cleverencode(s, cmd): if not util.binary(s): return dumbencode(s, cmd) return s def macdecode(s, cmd, **kwargs): if not util.binary(s): return macdumbdecode(s, cmd, **kwargs) return s def macencode(s, cmd): if not util.binary(s): return macdumbencode(s, cmd) return s _filters = { 'dumbdecode:': dumbdecode, 'dumbencode:': dumbencode, 'cleverdecode:': cleverdecode, 'cleverencode:': cleverencode, 'macdumbdecode:': macdumbdecode, 'macdumbencode:': macdumbencode, 'macdecode:': macdecode, 'macencode:': macencode, } def forbidnewline(ui, repo, hooktype, node, newline, **kwargs): halt = False seen = set() # we try to walk changesets in reverse order from newest to # oldest, so that if we see a file multiple times, we take the # newest version as canonical. this prevents us from blocking a # changegroup that contains an unacceptable commit followed later # by a commit that fixes the problem. tip = repo['tip'] for rev in xrange(len(repo) - 1, repo[node].rev() - 1, -1): c = repo[rev] for f in c.files(): if f in seen or f not in tip or f not in c: continue seen.add(f) data = c[f].data() if not util.binary(data) and newline in data: if not halt: ui.warn(_('attempt to commit or push text file(s) ' 'using %s line endings\n') % newlinestr[newline]) ui.warn(_('in %s: %s\n') % (short(c.node()), f)) halt = True if halt and hooktype == 'pretxnchangegroup': crlf = newlinestr[newline].lower() filter = filterstr[newline] ui.warn(_('\nTo prevent this mistake in your local repository,\n' 'add to Mercurial.ini or .hg/hgrc:\n' '\n' '[hooks]\n' 'pretxncommit.%s = python:hgext.win32text.forbid%s\n' '\n' 'and also consider adding:\n' '\n' '[extensions]\n' 'win32text =\n' '[encode]\n' '** = %sencode:\n' '[decode]\n' '** = %sdecode:\n') % (crlf, crlf, filter, filter)) return halt def forbidcrlf(ui, repo, hooktype, node, **kwargs): return forbidnewline(ui, repo, hooktype, node, '\r\n', **kwargs) def forbidcr(ui, repo, hooktype, node, **kwargs): return forbidnewline(ui, repo, hooktype, node, '\r', **kwargs) def reposetup(ui, repo): if not repo.local(): return for name, fn in _filters.iteritems(): repo.adddatafilter(name, fn) def extsetup(ui): # deprecated config: win32text.warn if ui.configbool('win32text', 'warn', True): ui.warn(_("win32text is deprecated: " "https://mercurial-scm.org/wiki/Win32TextExtension\n"))