Author: Armin Rigo <ar...@tunes.org>
Branch: py3.5
Changeset: r89045:d86691a0c3ca
Date: 2016-12-13 15:48 +0100
http://bitbucket.org/pypy/pypy/changeset/d86691a0c3ca/
Log: CPython's ``sys.settrace()`` sometimes reports an ``exception`` at
the end of ``for`` or ``yield from`` lines for the
``StopIteration``, and sometimes not. The problem is that it occurs
in an ill-defined subset of cases. PyPy attempts to emulate that but
the precise set of cases is not exactly the same.
diff --git a/pypy/doc/cpython_differences.rst b/pypy/doc/cpython_differences.rst
--- a/pypy/doc/cpython_differences.rst
+++ b/pypy/doc/cpython_differences.rst
@@ -478,6 +478,12 @@
from the Makefile used to build the interpreter. PyPy should bake the values
in during compilation, but does not do that yet.
+* CPython's ``sys.settrace()`` sometimes reports an ``exception`` at the
+ end of ``for`` or ``yield from`` lines for the ``StopIteration``, and
+ sometimes not. The problem is that it occurs in an ill-defined subset
+ of cases. PyPy attempts to emulate that but the precise set of cases
+ is not exactly the same.
+
.. _`is ignored in PyPy`: http://bugs.python.org/issue14621
.. _`little point`:
http://events.ccc.de/congress/2012/Fahrplan/events/5152.en.html
.. _`#2072`: https://bitbucket.org/pypy/pypy/issue/2072/
diff --git a/pypy/interpreter/error.py b/pypy/interpreter/error.py
--- a/pypy/interpreter/error.py
+++ b/pypy/interpreter/error.py
@@ -309,6 +309,9 @@
tb.frame.mark_as_escaped()
return tb
+ def has_any_traceback(self):
+ return self._application_traceback is not None
+
def set_cause(self, space, w_cause):
if w_cause is None:
return
diff --git a/pypy/interpreter/generator.py b/pypy/interpreter/generator.py
--- a/pypy/interpreter/generator.py
+++ b/pypy/interpreter/generator.py
@@ -185,7 +185,7 @@
if not e.match(space, space.w_StopIteration):
raise
e.normalize_exception(space)
- space.getexecutioncontext().exception_trace(frame, e)
+ frame._report_stopiteration_sometimes(w_yf, e)
try:
w_stop_value = space.getattr(e.get_w_value(space),
space.wrap("value"))
diff --git a/pypy/interpreter/pyopcode.py b/pypy/interpreter/pyopcode.py
--- a/pypy/interpreter/pyopcode.py
+++ b/pypy/interpreter/pyopcode.py
@@ -1154,13 +1154,31 @@
if not e.match(self.space, self.space.w_StopIteration):
raise
# iterator exhausted
- self.space.getexecutioncontext().exception_trace(self, e)
+ self._report_stopiteration_sometimes(w_iterator, e)
self.popvalue()
next_instr += jumpby
else:
self.pushvalue(w_nextitem)
return next_instr
+ def _report_stopiteration_sometimes(self, w_iterator, operr):
+ # CPython 3.5 calls the exception trace in an ill-defined subset
+ # of cases: only if tp_iternext returned NULL and set a
+ # StopIteration exception, but not if tp_iternext returned NULL
+ # *without* setting an exception. We can't easily emulate that
+ # behavior at this point. For example, the generator's
+ # tp_iternext uses one or other case depending on whether the
+ # generator is already exhausted or just exhausted now. We'll
+ # classify that as a CPython incompatibility and use an
+ # approximative rule: if w_iterator is a generator-iterator,
+ # we always report it; if operr has already a stack trace
+ # attached (likely from a custom __iter__() method), we also
+ # report it; in other cases, we don't.
+ from pypy.interpreter.generator import GeneratorOrCoroutine
+ if (isinstance(w_iterator, GeneratorOrCoroutine) or
+ operr.has_any_traceback()):
+ self.space.getexecutioncontext().exception_trace(self, operr)
+
def FOR_LOOP(self, oparg, next_instr):
raise BytecodeCorruption("old opcode, no longer in use")
diff --git a/pypy/interpreter/test/test_pyframe.py
b/pypy/interpreter/test/test_pyframe.py
--- a/pypy/interpreter/test/test_pyframe.py
+++ b/pypy/interpreter/test/test_pyframe.py
@@ -666,10 +666,33 @@
sys.settrace(None)
print('seen:', seen)
# on Python 3 we get an extra 'exception' when 'for' catches
- # StopIteration
+ # StopIteration (but not always! mess)
assert seen == ['call', 'line', 'call', 'return', 'exception',
'return']
assert frames[-2].f_code.co_name == 'g'
+ def test_nongenerator_trace_stopiteration(self):
+ import sys
+ gen = iter([5])
+ assert next(gen) == 5
+ seen = []
+ frames = []
+ def trace_func(frame, event, *args):
+ print('TRACE:', frame, event, args)
+ seen.append(event)
+ frames.append(frame)
+ return trace_func
+ def g():
+ for x in gen:
+ never_entered
+ sys.settrace(trace_func)
+ g()
+ sys.settrace(None)
+ print('seen:', seen)
+ # hack: don't report the StopIteration for some "simple"
+ # iterators.
+ assert seen == ['call', 'line', 'return']
+ assert frames[-2].f_code.co_name == 'g'
+
def test_yieldfrom_trace_stopiteration(self): """
import sys
def f2():
@@ -726,6 +749,30 @@
assert frames[-2].f_code.co_name == 'g'
"""
+ def test_yieldfrom_trace_stopiteration_3(self): """
+ import sys
+ def f():
+ yield from []
+ gen = f()
+ seen = []
+ frames = []
+ def trace_func(frame, event, *args):
+ print('TRACE:', frame, event, args)
+ seen.append(event)
+ frames.append(frame)
+ return trace_func
+ def g():
+ for x in gen:
+ never_entered
+ sys.settrace(trace_func)
+ g() # invokes next_yield_from() from YIELD_FROM()
+ sys.settrace(None)
+ print('seen:', seen)
+ assert seen == ['call', 'line', 'call', 'line',
+ 'return', 'exception', 'return']
+ assert frames[-4].f_code.co_name == 'f'
+ """
+
def test_clear_locals(self):
def make_frames():
def outer():
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