Skip to content

[3.6] bpo-31232: Backport custom print rshift message #3155

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
ncoghlan merged 2 commits into from
Aug 19, 2017
Merged

[3.6] bpo-31232: Backport custom print rshift message #3155

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
b1e3512
bpo-30721: Show correct syntax hint in Py3 when using Py2 redirection…
CuriousLearner Aug 18, 2017
c6ff845
bpo-30721: Add missing '?' to new error message (GH-3131)
CuriousLearner Aug 18, 2017
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
33 changes: 33 additions & 0 deletions Lib/test/test_print.py
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -1,4 +1,5 @@
import unittest
import sys
from io import StringIO

from test import support
Expand Down Expand Up @@ -155,6 +156,38 @@ def test_string_with_excessive_whitespace(self):

self.assertIn('print("Hello World", end=" ")', str(context.exception))

def test_stream_redirection_hint_for_py2_migration(self):
# Test correct hint produced for Py2 redirection syntax
with self.assertRaises(TypeError) as context:
print >> sys.stderr, "message"
self.assertIn('Did you mean "print(<message>, '
'file=<output_stream>)"?', str(context.exception))

# Test correct hint is produced in the case where RHS implements
# __rrshift__ but returns NotImplemented
with self.assertRaises(TypeError) as context:
print >> 42
self.assertIn('Did you mean "print(<message>, '
'file=<output_stream>)"?', str(context.exception))

# Test stream redirection hint is specific to print
with self.assertRaises(TypeError) as context:
max >> sys.stderr
self.assertNotIn('Did you mean ', str(context.exception))

# Test stream redirection hint is specific to rshift
with self.assertRaises(TypeError) as context:
print << sys.stderr
self.assertNotIn('Did you mean', str(context.exception))

# Ensure right operand implementing rrshift still works
class OverrideRRShift:
def __rrshift__(self, lhs):
return 42 # Force result independent of LHS

self.assertEqual(print >> OverrideRRShift(), 42)



if __name__ == "__main__":
unittest.main()
2 changes: 2 additions & 0 deletions Misc/NEWS.d/next/Core and Builtins/2017-08-18-15-15-20.bpo-30721.Hmc56z.rst
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,2 @@
``print`` now shows correct usage hint for using Python 2 redirection
syntax. Patch by Sanyam Khurana.
15 changes: 15 additions & 0 deletions Objects/abstract.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -809,6 +809,21 @@ binary_op(PyObject *v, PyObject *w, const int op_slot, const char *op_name)
PyObject *result = binary_op1(v, w, op_slot);
if (result == Py_NotImplemented) {
Py_DECREF(result);

if (op_slot == NB_SLOT(nb_rshift) &&
PyCFunction_Check(v) &&
strcmp(((PyCFunctionObject *)v)->m_ml->ml_name, "print") == 0)
{
PyErr_Format(PyExc_TypeError,
"unsupported operand type(s) for %.100s: "
"'%.100s' and '%.100s'. Did you mean \"print(<message>, "
"file=<output_stream>)\"?",
op_name,
v->ob_type->tp_name,
w->ob_type->tp_name);
return NULL;
}

return binop_type_error(v, w, op_name);
}
return result;
Expand Down