mirror of
https://github.com/thegeeklab/ansible-later.git
synced 2024-11-14 17:20:39 +00:00
1081 lines
40 KiB
Python
1081 lines
40 KiB
Python
"""Rewrite assertion AST to produce nice error messages"""
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from __future__ import absolute_import
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from __future__ import division
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from __future__ import print_function
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import ast
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import errno
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import imp
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import itertools
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import marshal
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import os
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import re
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import string
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import struct
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import sys
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import types
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import atomicwrites
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import py
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import six
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from _pytest._io.saferepr import saferepr
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from _pytest.assertion import util
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from _pytest.assertion.util import ( # noqa: F401
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format_explanation as _format_explanation,
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)
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from _pytest.compat import spec_from_file_location
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from _pytest.pathlib import fnmatch_ex
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from _pytest.pathlib import PurePath
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# pytest caches rewritten pycs in __pycache__.
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if hasattr(imp, "get_tag"):
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PYTEST_TAG = imp.get_tag() + "-PYTEST"
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else:
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if hasattr(sys, "pypy_version_info"):
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impl = "pypy"
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elif sys.platform == "java":
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impl = "jython"
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else:
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impl = "cpython"
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ver = sys.version_info
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PYTEST_TAG = "%s-%s%s-PYTEST" % (impl, ver[0], ver[1])
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del ver, impl
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PYC_EXT = ".py" + (__debug__ and "c" or "o")
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PYC_TAIL = "." + PYTEST_TAG + PYC_EXT
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ASCII_IS_DEFAULT_ENCODING = sys.version_info[0] < 3
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if sys.version_info >= (3, 5):
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ast_Call = ast.Call
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else:
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def ast_Call(a, b, c):
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return ast.Call(a, b, c, None, None)
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class AssertionRewritingHook(object):
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"""PEP302 Import hook which rewrites asserts."""
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def __init__(self, config):
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self.config = config
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self.fnpats = config.getini("python_files")
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self.session = None
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self.modules = {}
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self._rewritten_names = set()
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self._register_with_pkg_resources()
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self._must_rewrite = set()
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# flag to guard against trying to rewrite a pyc file while we are already writing another pyc file,
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# which might result in infinite recursion (#3506)
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self._writing_pyc = False
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self._basenames_to_check_rewrite = {"conftest"}
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self._marked_for_rewrite_cache = {}
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self._session_paths_checked = False
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def set_session(self, session):
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self.session = session
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self._session_paths_checked = False
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def _imp_find_module(self, name, path=None):
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"""Indirection so we can mock calls to find_module originated from the hook during testing"""
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return imp.find_module(name, path)
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def find_module(self, name, path=None):
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if self._writing_pyc:
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return None
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state = self.config._assertstate
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if self._early_rewrite_bailout(name, state):
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return None
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state.trace("find_module called for: %s" % name)
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names = name.rsplit(".", 1)
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lastname = names[-1]
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pth = None
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if path is not None:
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# Starting with Python 3.3, path is a _NamespacePath(), which
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# causes problems if not converted to list.
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path = list(path)
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if len(path) == 1:
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pth = path[0]
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if pth is None:
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try:
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fd, fn, desc = self._imp_find_module(lastname, path)
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except ImportError:
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return None
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if fd is not None:
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fd.close()
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tp = desc[2]
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if tp == imp.PY_COMPILED:
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if hasattr(imp, "source_from_cache"):
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try:
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fn = imp.source_from_cache(fn)
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except ValueError:
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# Python 3 doesn't like orphaned but still-importable
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# .pyc files.
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fn = fn[:-1]
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else:
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fn = fn[:-1]
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elif tp != imp.PY_SOURCE:
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# Don't know what this is.
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return None
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else:
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fn = os.path.join(pth, name.rpartition(".")[2] + ".py")
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fn_pypath = py.path.local(fn)
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if not self._should_rewrite(name, fn_pypath, state):
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return None
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self._rewritten_names.add(name)
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# The requested module looks like a test file, so rewrite it. This is
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# the most magical part of the process: load the source, rewrite the
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# asserts, and load the rewritten source. We also cache the rewritten
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# module code in a special pyc. We must be aware of the possibility of
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# concurrent pytest processes rewriting and loading pycs. To avoid
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# tricky race conditions, we maintain the following invariant: The
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# cached pyc is always a complete, valid pyc. Operations on it must be
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# atomic. POSIX's atomic rename comes in handy.
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write = not sys.dont_write_bytecode
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cache_dir = os.path.join(fn_pypath.dirname, "__pycache__")
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if write:
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try:
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os.mkdir(cache_dir)
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except OSError:
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e = sys.exc_info()[1].errno
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if e == errno.EEXIST:
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# Either the __pycache__ directory already exists (the
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# common case) or it's blocked by a non-dir node. In the
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# latter case, we'll ignore it in _write_pyc.
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pass
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elif e in [errno.ENOENT, errno.ENOTDIR]:
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# One of the path components was not a directory, likely
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# because we're in a zip file.
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write = False
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elif e in [errno.EACCES, errno.EROFS, errno.EPERM]:
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state.trace("read only directory: %r" % fn_pypath.dirname)
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write = False
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else:
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raise
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cache_name = fn_pypath.basename[:-3] + PYC_TAIL
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pyc = os.path.join(cache_dir, cache_name)
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# Notice that even if we're in a read-only directory, I'm going
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# to check for a cached pyc. This may not be optimal...
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co = _read_pyc(fn_pypath, pyc, state.trace)
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if co is None:
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state.trace("rewriting %r" % (fn,))
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source_stat, co = _rewrite_test(self.config, fn_pypath)
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if co is None:
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# Probably a SyntaxError in the test.
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return None
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if write:
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self._writing_pyc = True
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try:
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_write_pyc(state, co, source_stat, pyc)
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finally:
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self._writing_pyc = False
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else:
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state.trace("found cached rewritten pyc for %r" % (fn,))
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self.modules[name] = co, pyc
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return self
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def _early_rewrite_bailout(self, name, state):
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"""
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This is a fast way to get out of rewriting modules. Profiling has
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shown that the call to imp.find_module (inside of the find_module
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from this class) is a major slowdown, so, this method tries to
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filter what we're sure won't be rewritten before getting to it.
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"""
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if self.session is not None and not self._session_paths_checked:
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self._session_paths_checked = True
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for path in self.session._initialpaths:
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# Make something as c:/projects/my_project/path.py ->
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# ['c:', 'projects', 'my_project', 'path.py']
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parts = str(path).split(os.path.sep)
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# add 'path' to basenames to be checked.
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self._basenames_to_check_rewrite.add(os.path.splitext(parts[-1])[0])
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# Note: conftest already by default in _basenames_to_check_rewrite.
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parts = name.split(".")
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if parts[-1] in self._basenames_to_check_rewrite:
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return False
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# For matching the name it must be as if it was a filename.
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path = PurePath(os.path.sep.join(parts) + ".py")
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for pat in self.fnpats:
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# if the pattern contains subdirectories ("tests/**.py" for example) we can't bail out based
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# on the name alone because we need to match against the full path
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if os.path.dirname(pat):
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return False
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if fnmatch_ex(pat, path):
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return False
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if self._is_marked_for_rewrite(name, state):
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return False
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state.trace("early skip of rewriting module: %s" % (name,))
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return True
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def _should_rewrite(self, name, fn_pypath, state):
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# always rewrite conftest files
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fn = str(fn_pypath)
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if fn_pypath.basename == "conftest.py":
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state.trace("rewriting conftest file: %r" % (fn,))
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return True
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if self.session is not None:
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if self.session.isinitpath(fn):
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state.trace("matched test file (was specified on cmdline): %r" % (fn,))
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return True
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# modules not passed explicitly on the command line are only
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# rewritten if they match the naming convention for test files
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for pat in self.fnpats:
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if fn_pypath.fnmatch(pat):
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state.trace("matched test file %r" % (fn,))
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return True
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return self._is_marked_for_rewrite(name, state)
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def _is_marked_for_rewrite(self, name, state):
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try:
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return self._marked_for_rewrite_cache[name]
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except KeyError:
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for marked in self._must_rewrite:
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if name == marked or name.startswith(marked + "."):
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state.trace("matched marked file %r (from %r)" % (name, marked))
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self._marked_for_rewrite_cache[name] = True
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return True
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self._marked_for_rewrite_cache[name] = False
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return False
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def mark_rewrite(self, *names):
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"""Mark import names as needing to be rewritten.
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The named module or package as well as any nested modules will
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be rewritten on import.
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"""
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already_imported = (
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set(names).intersection(sys.modules).difference(self._rewritten_names)
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)
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for name in already_imported:
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if not AssertionRewriter.is_rewrite_disabled(
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sys.modules[name].__doc__ or ""
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):
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self._warn_already_imported(name)
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self._must_rewrite.update(names)
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self._marked_for_rewrite_cache.clear()
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def _warn_already_imported(self, name):
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from _pytest.warning_types import PytestWarning
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from _pytest.warnings import _issue_warning_captured
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_issue_warning_captured(
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PytestWarning("Module already imported so cannot be rewritten: %s" % name),
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self.config.hook,
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stacklevel=5,
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)
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def load_module(self, name):
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co, pyc = self.modules.pop(name)
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if name in sys.modules:
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# If there is an existing module object named 'fullname' in
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# sys.modules, the loader must use that existing module. (Otherwise,
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# the reload() builtin will not work correctly.)
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mod = sys.modules[name]
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else:
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# I wish I could just call imp.load_compiled here, but __file__ has to
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# be set properly. In Python 3.2+, this all would be handled correctly
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# by load_compiled.
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mod = sys.modules[name] = imp.new_module(name)
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try:
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mod.__file__ = co.co_filename
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# Normally, this attribute is 3.2+.
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mod.__cached__ = pyc
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mod.__loader__ = self
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# Normally, this attribute is 3.4+
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mod.__spec__ = spec_from_file_location(name, co.co_filename, loader=self)
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six.exec_(co, mod.__dict__)
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except: # noqa
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if name in sys.modules:
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del sys.modules[name]
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raise
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return sys.modules[name]
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def is_package(self, name):
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try:
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fd, fn, desc = self._imp_find_module(name)
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except ImportError:
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return False
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if fd is not None:
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fd.close()
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tp = desc[2]
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return tp == imp.PKG_DIRECTORY
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@classmethod
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def _register_with_pkg_resources(cls):
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"""
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Ensure package resources can be loaded from this loader. May be called
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multiple times, as the operation is idempotent.
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"""
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try:
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import pkg_resources
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# access an attribute in case a deferred importer is present
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pkg_resources.__name__
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except ImportError:
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return
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# Since pytest tests are always located in the file system, the
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# DefaultProvider is appropriate.
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pkg_resources.register_loader_type(cls, pkg_resources.DefaultProvider)
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def get_data(self, pathname):
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"""Optional PEP302 get_data API.
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"""
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with open(pathname, "rb") as f:
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return f.read()
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def _write_pyc(state, co, source_stat, pyc):
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# Technically, we don't have to have the same pyc format as
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# (C)Python, since these "pycs" should never be seen by builtin
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# import. However, there's little reason deviate, and I hope
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# sometime to be able to use imp.load_compiled to load them. (See
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# the comment in load_module above.)
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try:
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with atomicwrites.atomic_write(pyc, mode="wb", overwrite=True) as fp:
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fp.write(imp.get_magic())
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# as of now, bytecode header expects 32-bit numbers for size and mtime (#4903)
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mtime = int(source_stat.mtime) & 0xFFFFFFFF
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size = source_stat.size & 0xFFFFFFFF
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# "<LL" stands for 2 unsigned longs, little-ending
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fp.write(struct.pack("<LL", mtime, size))
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fp.write(marshal.dumps(co))
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except EnvironmentError as e:
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state.trace("error writing pyc file at %s: errno=%s" % (pyc, e.errno))
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# we ignore any failure to write the cache file
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# there are many reasons, permission-denied, __pycache__ being a
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# file etc.
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return False
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return True
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RN = "\r\n".encode("utf-8")
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N = "\n".encode("utf-8")
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cookie_re = re.compile(r"^[ \t\f]*#.*coding[:=][ \t]*[-\w.]+")
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BOM_UTF8 = "\xef\xbb\xbf"
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def _rewrite_test(config, fn):
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"""Try to read and rewrite *fn* and return the code object."""
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state = config._assertstate
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try:
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stat = fn.stat()
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source = fn.read("rb")
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except EnvironmentError:
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return None, None
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if ASCII_IS_DEFAULT_ENCODING:
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# ASCII is the default encoding in Python 2. Without a coding
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# declaration, Python 2 will complain about any bytes in the file
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# outside the ASCII range. Sadly, this behavior does not extend to
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# compile() or ast.parse(), which prefer to interpret the bytes as
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# latin-1. (At least they properly handle explicit coding cookies.) To
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# preserve this error behavior, we could force ast.parse() to use ASCII
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# as the encoding by inserting a coding cookie. Unfortunately, that
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# messes up line numbers. Thus, we have to check ourselves if anything
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# is outside the ASCII range in the case no encoding is explicitly
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# declared. For more context, see issue #269. Yay for Python 3 which
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# gets this right.
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end1 = source.find("\n")
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end2 = source.find("\n", end1 + 1)
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if (
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not source.startswith(BOM_UTF8)
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and cookie_re.match(source[0:end1]) is None
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and cookie_re.match(source[end1 + 1 : end2]) is None
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):
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if hasattr(state, "_indecode"):
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# encodings imported us again, so don't rewrite.
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return None, None
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state._indecode = True
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try:
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try:
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source.decode("ascii")
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except UnicodeDecodeError:
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# Let it fail in real import.
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return None, None
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finally:
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del state._indecode
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try:
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tree = ast.parse(source, filename=fn.strpath)
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except SyntaxError:
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# Let this pop up again in the real import.
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state.trace("failed to parse: %r" % (fn,))
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return None, None
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rewrite_asserts(tree, fn, config)
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try:
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co = compile(tree, fn.strpath, "exec", dont_inherit=True)
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except SyntaxError:
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# It's possible that this error is from some bug in the
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# assertion rewriting, but I don't know of a fast way to tell.
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state.trace("failed to compile: %r" % (fn,))
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return None, None
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return stat, co
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def _read_pyc(source, pyc, trace=lambda x: None):
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"""Possibly read a pytest pyc containing rewritten code.
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Return rewritten code if successful or None if not.
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"""
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try:
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fp = open(pyc, "rb")
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except IOError:
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return None
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with fp:
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try:
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mtime = int(source.mtime())
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size = source.size()
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data = fp.read(12)
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except EnvironmentError as e:
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trace("_read_pyc(%s): EnvironmentError %s" % (source, e))
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return None
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# Check for invalid or out of date pyc file.
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if (
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len(data) != 12
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or data[:4] != imp.get_magic()
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or struct.unpack("<LL", data[4:]) != (mtime & 0xFFFFFFFF, size & 0xFFFFFFFF)
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):
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trace("_read_pyc(%s): invalid or out of date pyc" % source)
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return None
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try:
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co = marshal.load(fp)
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except Exception as e:
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trace("_read_pyc(%s): marshal.load error %s" % (source, e))
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return None
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if not isinstance(co, types.CodeType):
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trace("_read_pyc(%s): not a code object" % source)
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return None
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return co
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def rewrite_asserts(mod, module_path=None, config=None):
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"""Rewrite the assert statements in mod."""
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AssertionRewriter(module_path, config).run(mod)
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def _saferepr(obj):
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"""Get a safe repr of an object for assertion error messages.
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The assertion formatting (util.format_explanation()) requires
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newlines to be escaped since they are a special character for it.
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Normally assertion.util.format_explanation() does this but for a
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custom repr it is possible to contain one of the special escape
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sequences, especially '\n{' and '\n}' are likely to be present in
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JSON reprs.
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"""
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r = saferepr(obj)
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# only occurs in python2.x, repr must return text in python3+
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if isinstance(r, bytes):
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# Represent unprintable bytes as `\x##`
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r = u"".join(
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u"\\x{:x}".format(ord(c)) if c not in string.printable else c.decode()
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for c in r
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)
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return r.replace(u"\n", u"\\n")
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|
|
def _format_assertmsg(obj):
|
|
"""Format the custom assertion message given.
|
|
|
|
For strings this simply replaces newlines with '\n~' so that
|
|
util.format_explanation() will preserve them instead of escaping
|
|
newlines. For other objects saferepr() is used first.
|
|
|
|
"""
|
|
# reprlib appears to have a bug which means that if a string
|
|
# contains a newline it gets escaped, however if an object has a
|
|
# .__repr__() which contains newlines it does not get escaped.
|
|
# However in either case we want to preserve the newline.
|
|
replaces = [(u"\n", u"\n~"), (u"%", u"%%")]
|
|
if not isinstance(obj, six.string_types):
|
|
obj = saferepr(obj)
|
|
replaces.append((u"\\n", u"\n~"))
|
|
|
|
if isinstance(obj, bytes):
|
|
replaces = [(r1.encode(), r2.encode()) for r1, r2 in replaces]
|
|
|
|
for r1, r2 in replaces:
|
|
obj = obj.replace(r1, r2)
|
|
|
|
return obj
|
|
|
|
|
|
def _should_repr_global_name(obj):
|
|
if callable(obj):
|
|
return False
|
|
|
|
try:
|
|
return not hasattr(obj, "__name__")
|
|
except Exception:
|
|
return True
|
|
|
|
|
|
def _format_boolop(explanations, is_or):
|
|
explanation = "(" + (is_or and " or " or " and ").join(explanations) + ")"
|
|
if isinstance(explanation, six.text_type):
|
|
return explanation.replace(u"%", u"%%")
|
|
else:
|
|
return explanation.replace(b"%", b"%%")
|
|
|
|
|
|
def _call_reprcompare(ops, results, expls, each_obj):
|
|
for i, res, expl in zip(range(len(ops)), results, expls):
|
|
try:
|
|
done = not res
|
|
except Exception:
|
|
done = True
|
|
if done:
|
|
break
|
|
if util._reprcompare is not None:
|
|
custom = util._reprcompare(ops[i], each_obj[i], each_obj[i + 1])
|
|
if custom is not None:
|
|
return custom
|
|
return expl
|
|
|
|
|
|
unary_map = {ast.Not: "not %s", ast.Invert: "~%s", ast.USub: "-%s", ast.UAdd: "+%s"}
|
|
|
|
binop_map = {
|
|
ast.BitOr: "|",
|
|
ast.BitXor: "^",
|
|
ast.BitAnd: "&",
|
|
ast.LShift: "<<",
|
|
ast.RShift: ">>",
|
|
ast.Add: "+",
|
|
ast.Sub: "-",
|
|
ast.Mult: "*",
|
|
ast.Div: "/",
|
|
ast.FloorDiv: "//",
|
|
ast.Mod: "%%", # escaped for string formatting
|
|
ast.Eq: "==",
|
|
ast.NotEq: "!=",
|
|
ast.Lt: "<",
|
|
ast.LtE: "<=",
|
|
ast.Gt: ">",
|
|
ast.GtE: ">=",
|
|
ast.Pow: "**",
|
|
ast.Is: "is",
|
|
ast.IsNot: "is not",
|
|
ast.In: "in",
|
|
ast.NotIn: "not in",
|
|
}
|
|
# Python 3.5+ compatibility
|
|
try:
|
|
binop_map[ast.MatMult] = "@"
|
|
except AttributeError:
|
|
pass
|
|
|
|
# Python 3.4+ compatibility
|
|
if hasattr(ast, "NameConstant"):
|
|
_NameConstant = ast.NameConstant
|
|
else:
|
|
|
|
def _NameConstant(c):
|
|
return ast.Name(str(c), ast.Load())
|
|
|
|
|
|
def set_location(node, lineno, col_offset):
|
|
"""Set node location information recursively."""
|
|
|
|
def _fix(node, lineno, col_offset):
|
|
if "lineno" in node._attributes:
|
|
node.lineno = lineno
|
|
if "col_offset" in node._attributes:
|
|
node.col_offset = col_offset
|
|
for child in ast.iter_child_nodes(node):
|
|
_fix(child, lineno, col_offset)
|
|
|
|
_fix(node, lineno, col_offset)
|
|
return node
|
|
|
|
|
|
class AssertionRewriter(ast.NodeVisitor):
|
|
"""Assertion rewriting implementation.
|
|
|
|
The main entrypoint is to call .run() with an ast.Module instance,
|
|
this will then find all the assert statements and rewrite them to
|
|
provide intermediate values and a detailed assertion error. See
|
|
http://pybites.blogspot.be/2011/07/behind-scenes-of-pytests-new-assertion.html
|
|
for an overview of how this works.
|
|
|
|
The entry point here is .run() which will iterate over all the
|
|
statements in an ast.Module and for each ast.Assert statement it
|
|
finds call .visit() with it. Then .visit_Assert() takes over and
|
|
is responsible for creating new ast statements to replace the
|
|
original assert statement: it rewrites the test of an assertion
|
|
to provide intermediate values and replace it with an if statement
|
|
which raises an assertion error with a detailed explanation in
|
|
case the expression is false.
|
|
|
|
For this .visit_Assert() uses the visitor pattern to visit all the
|
|
AST nodes of the ast.Assert.test field, each visit call returning
|
|
an AST node and the corresponding explanation string. During this
|
|
state is kept in several instance attributes:
|
|
|
|
:statements: All the AST statements which will replace the assert
|
|
statement.
|
|
|
|
:variables: This is populated by .variable() with each variable
|
|
used by the statements so that they can all be set to None at
|
|
the end of the statements.
|
|
|
|
:variable_counter: Counter to create new unique variables needed
|
|
by statements. Variables are created using .variable() and
|
|
have the form of "@py_assert0".
|
|
|
|
:on_failure: The AST statements which will be executed if the
|
|
assertion test fails. This is the code which will construct
|
|
the failure message and raises the AssertionError.
|
|
|
|
:explanation_specifiers: A dict filled by .explanation_param()
|
|
with %-formatting placeholders and their corresponding
|
|
expressions to use in the building of an assertion message.
|
|
This is used by .pop_format_context() to build a message.
|
|
|
|
:stack: A stack of the explanation_specifiers dicts maintained by
|
|
.push_format_context() and .pop_format_context() which allows
|
|
to build another %-formatted string while already building one.
|
|
|
|
This state is reset on every new assert statement visited and used
|
|
by the other visitors.
|
|
|
|
"""
|
|
|
|
def __init__(self, module_path, config):
|
|
super(AssertionRewriter, self).__init__()
|
|
self.module_path = module_path
|
|
self.config = config
|
|
|
|
def run(self, mod):
|
|
"""Find all assert statements in *mod* and rewrite them."""
|
|
if not mod.body:
|
|
# Nothing to do.
|
|
return
|
|
# Insert some special imports at the top of the module but after any
|
|
# docstrings and __future__ imports.
|
|
aliases = [
|
|
ast.alias(six.moves.builtins.__name__, "@py_builtins"),
|
|
ast.alias("_pytest.assertion.rewrite", "@pytest_ar"),
|
|
]
|
|
doc = getattr(mod, "docstring", None)
|
|
expect_docstring = doc is None
|
|
if doc is not None and self.is_rewrite_disabled(doc):
|
|
return
|
|
pos = 0
|
|
lineno = 1
|
|
for item in mod.body:
|
|
if (
|
|
expect_docstring
|
|
and isinstance(item, ast.Expr)
|
|
and isinstance(item.value, ast.Str)
|
|
):
|
|
doc = item.value.s
|
|
if self.is_rewrite_disabled(doc):
|
|
return
|
|
expect_docstring = False
|
|
elif (
|
|
not isinstance(item, ast.ImportFrom)
|
|
or item.level > 0
|
|
or item.module != "__future__"
|
|
):
|
|
lineno = item.lineno
|
|
break
|
|
pos += 1
|
|
else:
|
|
lineno = item.lineno
|
|
imports = [
|
|
ast.Import([alias], lineno=lineno, col_offset=0) for alias in aliases
|
|
]
|
|
mod.body[pos:pos] = imports
|
|
# Collect asserts.
|
|
nodes = [mod]
|
|
while nodes:
|
|
node = nodes.pop()
|
|
for name, field in ast.iter_fields(node):
|
|
if isinstance(field, list):
|
|
new = []
|
|
for i, child in enumerate(field):
|
|
if isinstance(child, ast.Assert):
|
|
# Transform assert.
|
|
new.extend(self.visit(child))
|
|
else:
|
|
new.append(child)
|
|
if isinstance(child, ast.AST):
|
|
nodes.append(child)
|
|
setattr(node, name, new)
|
|
elif (
|
|
isinstance(field, ast.AST)
|
|
# Don't recurse into expressions as they can't contain
|
|
# asserts.
|
|
and not isinstance(field, ast.expr)
|
|
):
|
|
nodes.append(field)
|
|
|
|
@staticmethod
|
|
def is_rewrite_disabled(docstring):
|
|
return "PYTEST_DONT_REWRITE" in docstring
|
|
|
|
def variable(self):
|
|
"""Get a new variable."""
|
|
# Use a character invalid in python identifiers to avoid clashing.
|
|
name = "@py_assert" + str(next(self.variable_counter))
|
|
self.variables.append(name)
|
|
return name
|
|
|
|
def assign(self, expr):
|
|
"""Give *expr* a name."""
|
|
name = self.variable()
|
|
self.statements.append(ast.Assign([ast.Name(name, ast.Store())], expr))
|
|
return ast.Name(name, ast.Load())
|
|
|
|
def display(self, expr):
|
|
"""Call saferepr on the expression."""
|
|
return self.helper("saferepr", expr)
|
|
|
|
def helper(self, name, *args):
|
|
"""Call a helper in this module."""
|
|
py_name = ast.Name("@pytest_ar", ast.Load())
|
|
attr = ast.Attribute(py_name, "_" + name, ast.Load())
|
|
return ast_Call(attr, list(args), [])
|
|
|
|
def builtin(self, name):
|
|
"""Return the builtin called *name*."""
|
|
builtin_name = ast.Name("@py_builtins", ast.Load())
|
|
return ast.Attribute(builtin_name, name, ast.Load())
|
|
|
|
def explanation_param(self, expr):
|
|
"""Return a new named %-formatting placeholder for expr.
|
|
|
|
This creates a %-formatting placeholder for expr in the
|
|
current formatting context, e.g. ``%(py0)s``. The placeholder
|
|
and expr are placed in the current format context so that it
|
|
can be used on the next call to .pop_format_context().
|
|
|
|
"""
|
|
specifier = "py" + str(next(self.variable_counter))
|
|
self.explanation_specifiers[specifier] = expr
|
|
return "%(" + specifier + ")s"
|
|
|
|
def push_format_context(self):
|
|
"""Create a new formatting context.
|
|
|
|
The format context is used for when an explanation wants to
|
|
have a variable value formatted in the assertion message. In
|
|
this case the value required can be added using
|
|
.explanation_param(). Finally .pop_format_context() is used
|
|
to format a string of %-formatted values as added by
|
|
.explanation_param().
|
|
|
|
"""
|
|
self.explanation_specifiers = {}
|
|
self.stack.append(self.explanation_specifiers)
|
|
|
|
def pop_format_context(self, expl_expr):
|
|
"""Format the %-formatted string with current format context.
|
|
|
|
The expl_expr should be an ast.Str instance constructed from
|
|
the %-placeholders created by .explanation_param(). This will
|
|
add the required code to format said string to .on_failure and
|
|
return the ast.Name instance of the formatted string.
|
|
|
|
"""
|
|
current = self.stack.pop()
|
|
if self.stack:
|
|
self.explanation_specifiers = self.stack[-1]
|
|
keys = [ast.Str(key) for key in current.keys()]
|
|
format_dict = ast.Dict(keys, list(current.values()))
|
|
form = ast.BinOp(expl_expr, ast.Mod(), format_dict)
|
|
name = "@py_format" + str(next(self.variable_counter))
|
|
self.on_failure.append(ast.Assign([ast.Name(name, ast.Store())], form))
|
|
return ast.Name(name, ast.Load())
|
|
|
|
def generic_visit(self, node):
|
|
"""Handle expressions we don't have custom code for."""
|
|
assert isinstance(node, ast.expr)
|
|
res = self.assign(node)
|
|
return res, self.explanation_param(self.display(res))
|
|
|
|
def visit_Assert(self, assert_):
|
|
"""Return the AST statements to replace the ast.Assert instance.
|
|
|
|
This rewrites the test of an assertion to provide
|
|
intermediate values and replace it with an if statement which
|
|
raises an assertion error with a detailed explanation in case
|
|
the expression is false.
|
|
|
|
"""
|
|
if isinstance(assert_.test, ast.Tuple) and len(assert_.test.elts) >= 1:
|
|
from _pytest.warning_types import PytestWarning
|
|
import warnings
|
|
|
|
warnings.warn_explicit(
|
|
PytestWarning("assertion is always true, perhaps remove parentheses?"),
|
|
category=None,
|
|
filename=str(self.module_path),
|
|
lineno=assert_.lineno,
|
|
)
|
|
|
|
self.statements = []
|
|
self.variables = []
|
|
self.variable_counter = itertools.count()
|
|
self.stack = []
|
|
self.on_failure = []
|
|
self.push_format_context()
|
|
# Rewrite assert into a bunch of statements.
|
|
top_condition, explanation = self.visit(assert_.test)
|
|
# If in a test module, check if directly asserting None, in order to warn [Issue #3191]
|
|
if self.module_path is not None:
|
|
self.statements.append(
|
|
self.warn_about_none_ast(
|
|
top_condition, module_path=self.module_path, lineno=assert_.lineno
|
|
)
|
|
)
|
|
# Create failure message.
|
|
body = self.on_failure
|
|
negation = ast.UnaryOp(ast.Not(), top_condition)
|
|
self.statements.append(ast.If(negation, body, []))
|
|
if assert_.msg:
|
|
assertmsg = self.helper("format_assertmsg", assert_.msg)
|
|
explanation = "\n>assert " + explanation
|
|
else:
|
|
assertmsg = ast.Str("")
|
|
explanation = "assert " + explanation
|
|
template = ast.BinOp(assertmsg, ast.Add(), ast.Str(explanation))
|
|
msg = self.pop_format_context(template)
|
|
fmt = self.helper("format_explanation", msg)
|
|
err_name = ast.Name("AssertionError", ast.Load())
|
|
exc = ast_Call(err_name, [fmt], [])
|
|
if sys.version_info[0] >= 3:
|
|
raise_ = ast.Raise(exc, None)
|
|
else:
|
|
raise_ = ast.Raise(exc, None, None)
|
|
body.append(raise_)
|
|
# Clear temporary variables by setting them to None.
|
|
if self.variables:
|
|
variables = [ast.Name(name, ast.Store()) for name in self.variables]
|
|
clear = ast.Assign(variables, _NameConstant(None))
|
|
self.statements.append(clear)
|
|
# Fix line numbers.
|
|
for stmt in self.statements:
|
|
set_location(stmt, assert_.lineno, assert_.col_offset)
|
|
return self.statements
|
|
|
|
def warn_about_none_ast(self, node, module_path, lineno):
|
|
"""
|
|
Returns an AST issuing a warning if the value of node is `None`.
|
|
This is used to warn the user when asserting a function that asserts
|
|
internally already.
|
|
See issue #3191 for more details.
|
|
"""
|
|
|
|
# Using parse because it is different between py2 and py3.
|
|
AST_NONE = ast.parse("None").body[0].value
|
|
val_is_none = ast.Compare(node, [ast.Is()], [AST_NONE])
|
|
send_warning = ast.parse(
|
|
"""
|
|
from _pytest.warning_types import PytestWarning
|
|
from warnings import warn_explicit
|
|
warn_explicit(
|
|
PytestWarning('asserting the value None, please use "assert is None"'),
|
|
category=None,
|
|
filename={filename!r},
|
|
lineno={lineno},
|
|
)
|
|
""".format(
|
|
filename=module_path.strpath, lineno=lineno
|
|
)
|
|
).body
|
|
return ast.If(val_is_none, send_warning, [])
|
|
|
|
def visit_Name(self, name):
|
|
# Display the repr of the name if it's a local variable or
|
|
# _should_repr_global_name() thinks it's acceptable.
|
|
locs = ast_Call(self.builtin("locals"), [], [])
|
|
inlocs = ast.Compare(ast.Str(name.id), [ast.In()], [locs])
|
|
dorepr = self.helper("should_repr_global_name", name)
|
|
test = ast.BoolOp(ast.Or(), [inlocs, dorepr])
|
|
expr = ast.IfExp(test, self.display(name), ast.Str(name.id))
|
|
return name, self.explanation_param(expr)
|
|
|
|
def visit_BoolOp(self, boolop):
|
|
res_var = self.variable()
|
|
expl_list = self.assign(ast.List([], ast.Load()))
|
|
app = ast.Attribute(expl_list, "append", ast.Load())
|
|
is_or = int(isinstance(boolop.op, ast.Or))
|
|
body = save = self.statements
|
|
fail_save = self.on_failure
|
|
levels = len(boolop.values) - 1
|
|
self.push_format_context()
|
|
# Process each operand, short-circuting if needed.
|
|
for i, v in enumerate(boolop.values):
|
|
if i:
|
|
fail_inner = []
|
|
# cond is set in a prior loop iteration below
|
|
self.on_failure.append(ast.If(cond, fail_inner, [])) # noqa
|
|
self.on_failure = fail_inner
|
|
self.push_format_context()
|
|
res, expl = self.visit(v)
|
|
body.append(ast.Assign([ast.Name(res_var, ast.Store())], res))
|
|
expl_format = self.pop_format_context(ast.Str(expl))
|
|
call = ast_Call(app, [expl_format], [])
|
|
self.on_failure.append(ast.Expr(call))
|
|
if i < levels:
|
|
cond = res
|
|
if is_or:
|
|
cond = ast.UnaryOp(ast.Not(), cond)
|
|
inner = []
|
|
self.statements.append(ast.If(cond, inner, []))
|
|
self.statements = body = inner
|
|
self.statements = save
|
|
self.on_failure = fail_save
|
|
expl_template = self.helper("format_boolop", expl_list, ast.Num(is_or))
|
|
expl = self.pop_format_context(expl_template)
|
|
return ast.Name(res_var, ast.Load()), self.explanation_param(expl)
|
|
|
|
def visit_UnaryOp(self, unary):
|
|
pattern = unary_map[unary.op.__class__]
|
|
operand_res, operand_expl = self.visit(unary.operand)
|
|
res = self.assign(ast.UnaryOp(unary.op, operand_res))
|
|
return res, pattern % (operand_expl,)
|
|
|
|
def visit_BinOp(self, binop):
|
|
symbol = binop_map[binop.op.__class__]
|
|
left_expr, left_expl = self.visit(binop.left)
|
|
right_expr, right_expl = self.visit(binop.right)
|
|
explanation = "(%s %s %s)" % (left_expl, symbol, right_expl)
|
|
res = self.assign(ast.BinOp(left_expr, binop.op, right_expr))
|
|
return res, explanation
|
|
|
|
def visit_Call_35(self, call):
|
|
"""
|
|
visit `ast.Call` nodes on Python3.5 and after
|
|
"""
|
|
new_func, func_expl = self.visit(call.func)
|
|
arg_expls = []
|
|
new_args = []
|
|
new_kwargs = []
|
|
for arg in call.args:
|
|
res, expl = self.visit(arg)
|
|
arg_expls.append(expl)
|
|
new_args.append(res)
|
|
for keyword in call.keywords:
|
|
res, expl = self.visit(keyword.value)
|
|
new_kwargs.append(ast.keyword(keyword.arg, res))
|
|
if keyword.arg:
|
|
arg_expls.append(keyword.arg + "=" + expl)
|
|
else: # **args have `arg` keywords with an .arg of None
|
|
arg_expls.append("**" + expl)
|
|
|
|
expl = "%s(%s)" % (func_expl, ", ".join(arg_expls))
|
|
new_call = ast.Call(new_func, new_args, new_kwargs)
|
|
res = self.assign(new_call)
|
|
res_expl = self.explanation_param(self.display(res))
|
|
outer_expl = "%s\n{%s = %s\n}" % (res_expl, res_expl, expl)
|
|
return res, outer_expl
|
|
|
|
def visit_Starred(self, starred):
|
|
# From Python 3.5, a Starred node can appear in a function call
|
|
res, expl = self.visit(starred.value)
|
|
new_starred = ast.Starred(res, starred.ctx)
|
|
return new_starred, "*" + expl
|
|
|
|
def visit_Call_legacy(self, call):
|
|
"""
|
|
visit `ast.Call nodes on 3.4 and below`
|
|
"""
|
|
new_func, func_expl = self.visit(call.func)
|
|
arg_expls = []
|
|
new_args = []
|
|
new_kwargs = []
|
|
new_star = new_kwarg = None
|
|
for arg in call.args:
|
|
res, expl = self.visit(arg)
|
|
new_args.append(res)
|
|
arg_expls.append(expl)
|
|
for keyword in call.keywords:
|
|
res, expl = self.visit(keyword.value)
|
|
new_kwargs.append(ast.keyword(keyword.arg, res))
|
|
arg_expls.append(keyword.arg + "=" + expl)
|
|
if call.starargs:
|
|
new_star, expl = self.visit(call.starargs)
|
|
arg_expls.append("*" + expl)
|
|
if call.kwargs:
|
|
new_kwarg, expl = self.visit(call.kwargs)
|
|
arg_expls.append("**" + expl)
|
|
expl = "%s(%s)" % (func_expl, ", ".join(arg_expls))
|
|
new_call = ast.Call(new_func, new_args, new_kwargs, new_star, new_kwarg)
|
|
res = self.assign(new_call)
|
|
res_expl = self.explanation_param(self.display(res))
|
|
outer_expl = "%s\n{%s = %s\n}" % (res_expl, res_expl, expl)
|
|
return res, outer_expl
|
|
|
|
# ast.Call signature changed on 3.5,
|
|
# conditionally change which methods is named
|
|
# visit_Call depending on Python version
|
|
if sys.version_info >= (3, 5):
|
|
visit_Call = visit_Call_35
|
|
else:
|
|
visit_Call = visit_Call_legacy
|
|
|
|
def visit_Attribute(self, attr):
|
|
if not isinstance(attr.ctx, ast.Load):
|
|
return self.generic_visit(attr)
|
|
value, value_expl = self.visit(attr.value)
|
|
res = self.assign(ast.Attribute(value, attr.attr, ast.Load()))
|
|
res_expl = self.explanation_param(self.display(res))
|
|
pat = "%s\n{%s = %s.%s\n}"
|
|
expl = pat % (res_expl, res_expl, value_expl, attr.attr)
|
|
return res, expl
|
|
|
|
def visit_Compare(self, comp):
|
|
self.push_format_context()
|
|
left_res, left_expl = self.visit(comp.left)
|
|
if isinstance(comp.left, (ast.Compare, ast.BoolOp)):
|
|
left_expl = "({})".format(left_expl)
|
|
res_variables = [self.variable() for i in range(len(comp.ops))]
|
|
load_names = [ast.Name(v, ast.Load()) for v in res_variables]
|
|
store_names = [ast.Name(v, ast.Store()) for v in res_variables]
|
|
it = zip(range(len(comp.ops)), comp.ops, comp.comparators)
|
|
expls = []
|
|
syms = []
|
|
results = [left_res]
|
|
for i, op, next_operand in it:
|
|
next_res, next_expl = self.visit(next_operand)
|
|
if isinstance(next_operand, (ast.Compare, ast.BoolOp)):
|
|
next_expl = "({})".format(next_expl)
|
|
results.append(next_res)
|
|
sym = binop_map[op.__class__]
|
|
syms.append(ast.Str(sym))
|
|
expl = "%s %s %s" % (left_expl, sym, next_expl)
|
|
expls.append(ast.Str(expl))
|
|
res_expr = ast.Compare(left_res, [op], [next_res])
|
|
self.statements.append(ast.Assign([store_names[i]], res_expr))
|
|
left_res, left_expl = next_res, next_expl
|
|
# Use pytest.assertion.util._reprcompare if that's available.
|
|
expl_call = self.helper(
|
|
"call_reprcompare",
|
|
ast.Tuple(syms, ast.Load()),
|
|
ast.Tuple(load_names, ast.Load()),
|
|
ast.Tuple(expls, ast.Load()),
|
|
ast.Tuple(results, ast.Load()),
|
|
)
|
|
if len(comp.ops) > 1:
|
|
res = ast.BoolOp(ast.And(), load_names)
|
|
else:
|
|
res = load_names[0]
|
|
return res, self.explanation_param(self.pop_format_context(expl_call))
|