Remove assertion reinterpretation

The assertion reinterpretation is an old backwards compatibility
mode which was no longer being maintained on feature-parity with
the assertion rewriting mode.  It was also responsible for some
dubious patching of builtins and test with side-effects would
suddenly start passing.  Since re-writing has been the default for
a long time and plugins are now also re-written it is time to
retire reinterpretation.

CHANGELOG.rst

@@ -6,6 +6,10 @@
 A number of incompatible changes were made in this release, with the intent of removing features deprecated for a long
 time or change existing behaviors in order to make them less surprising/more useful.
 
+* Reinterpretation mode has now been removed. Only plain and rewrite
+ mode are available, consequently the ``--assert=reinterp`` option is
+ no longer available. Thanks `@flub`_ for the PR.
+
 * The following deprecated commandline options were removed:
 
  * ``--genscript``: no longer supported;

_pytest/_code/__init__.py

@@ -4,9 +4,6 @@
 from .code import Frame # noqa
 from .code import Traceback # noqa
 from .code import getrawcode # noqa
-from .code import patch_builtins # noqa
-from .code import unpatch_builtins # noqa
 from .source import Source # noqa
 from .source import compile_ as compile # noqa
 from .source import getfslineno # noqa
-

_pytest/_code/code.py

@@ -179,18 +179,6 @@ def getlocals(self):
  return self.frame.f_locals
  locals = property(getlocals, None, None, "locals of underlaying frame")
 
- def reinterpret(self):
- """Reinterpret the failing statement and returns a detailed information
- about what operations are performed."""
- from _pytest.assertion.reinterpret import reinterpret
- if self.exprinfo is None:
- source = py.builtin._totext(self.statement).strip()
- x = reinterpret(source, self.frame, should_fail=True)
- if not py.builtin._istext(x):
- raise TypeError("interpret returned non-string %r" % (x,))
- self.exprinfo = x
- return self.exprinfo
-
  def getfirstlinesource(self):
  # on Jython this firstlineno can be -1 apparently
  return max(self.frame.code.firstlineno, 0)
@@ -830,29 +818,6 @@ def toterminal(self, tw):
  tw.line("")
 
 
-
-oldbuiltins = {}
-
-def patch_builtins(assertion=True, compile=True):
- """ put compile and AssertionError builtins to Python's builtins. """
- if assertion:
- from _pytest.assertion import reinterpret
- l = oldbuiltins.setdefault('AssertionError', [])
- l.append(py.builtin.builtins.AssertionError)
- py.builtin.builtins.AssertionError = reinterpret.AssertionError
- if compile:
- import _pytest._code
- l = oldbuiltins.setdefault('compile', [])
- l.append(py.builtin.builtins.compile)
- py.builtin.builtins.compile = _pytest._code.compile
-
-def unpatch_builtins(assertion=True, compile=True):
- """ remove compile and AssertionError builtins from Python builtins. """
- if assertion:
- py.builtin.builtins.AssertionError = oldbuiltins['AssertionError'].pop()
- if compile:
- py.builtin.builtins.compile = oldbuiltins['compile'].pop()
-
 def getrawcode(obj, trycall=True):
  """ return code object for given function. """
  try:

_pytest/assertion/__init__.py

@@ -14,16 +14,14 @@ def pytest_addoption(parser):
  group.addoption('--assert',
  action="store",
  dest="assertmode",
- choices=("rewrite", "reinterp", "plain",),
+ choices=("rewrite", "plain",),
  default="rewrite",
  metavar="MODE",
- help="""control assertion debugging tools. 'plain'
- performs no assertion debugging. 'reinterp'
- reinterprets assert statements after they failed
- to provide assertion expression information.
- 'rewrite' (the default) rewrites assert
- statements in test modules on import to
- provide assert expression information. """)
+ help="""Control assertion debugging tools. 'plain'
+ performs no assertion debugging. 'rewrite'
+ (the default) rewrites assert statements in
+ test modules on import to provide assert
+ expression information.""")
 
 
 def pytest_namespace():
@@ -60,37 +58,21 @@ class AssertionState:
  def __init__(self, config, mode):
  self.mode = mode
  self.trace = config.trace.root.get("assertion")
+ self.hook = None
 
 
-def install_importhook(config, mode):
- if mode == "rewrite":
- try:
- import ast # noqa
- except ImportError:
- mode = "reinterp"
- else:
- # Both Jython and CPython 2.6.0 have AST bugs that make the
- # assertion rewriting hook malfunction.
- if (sys.platform.startswith('java') or
- sys.version_info[:3] == (2, 6, 0)):
- mode = "reinterp"
-
- config._assertstate = AssertionState(config, mode)
-
- _load_modules(mode)
- from _pytest.monkeypatch import MonkeyPatch
- m = MonkeyPatch()
- config._cleanup.append(m.undo)
- m.setattr(py.builtin.builtins, 'AssertionError',
- reinterpret.AssertionError) # noqa
-
- hook = None
- if mode == "rewrite":
- hook = rewrite.AssertionRewritingHook(config) # noqa
- sys.meta_path.insert(0, hook)
-
- config._assertstate.hook = hook
- config._assertstate.trace("configured with mode set to %r" % (mode,))
+def install_importhook(config):
+ """Try to install the rewrite hook, raise SystemError if it fails."""
+ # Both Jython and CPython 2.6.0 have AST bugs that make the
+ # assertion rewriting hook malfunction.
+ if (sys.platform.startswith('java') or
+ sys.version_info[:3] == (2, 6, 0)):
+ raise SystemError('rewrite not supported')
+
+ config._assertstate = AssertionState(config, 'rewrite')
+ config._assertstate.hook = hook = rewrite.AssertionRewritingHook(config)
+ sys.meta_path.insert(0, hook)
+ config._assertstate.trace('installed rewrite import hook')
  def undo():
  hook = config._assertstate.hook
  if hook is not None and hook in sys.meta_path:
@@ -169,13 +151,5 @@ def pytest_sessionfinish(session):
  assertstate.hook.set_session(None)
 
 
-def _load_modules(mode):
- """Lazily import assertion related code."""
- global rewrite, reinterpret
- from _pytest.assertion import reinterpret # noqa
- if mode == "rewrite":
- from _pytest.assertion import rewrite # noqa
-
-
 # Expose this plugin's implementation for the pytest_assertrepr_compare hook
 pytest_assertrepr_compare = util.assertrepr_compare