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bpo-46167: Allow assert statements with parentheses #30247

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bpo-46167: Allow assert statements with parentheses #30247

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4 changes: 3 additions & 1 deletion Grammar/python.gram
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Original file line number Diff line number Diff line change
Expand Up @@ -192,7 +192,9 @@ del_stmt[stmt_ty]:

yield_stmt[stmt_ty]: y=yield_expr { _PyAST_Expr(y, EXTRA) }

assert_stmt[stmt_ty]: 'assert' a=expression b=[',' z=expression { z }] { _PyAST_Assert(a, b, EXTRA) }
assert_stmt[stmt_ty]:
| 'assert' '(' a=expression ',' b=expression [','] ')' &(NEWLINE | '&') { _PyAST_Assert(a, b, EXTRA) }
| 'assert' a=expression b=[',' z=expression { z }] { _PyAST_Assert(a, b, EXTRA) }

import_stmt[stmt_ty]: import_name | import_from

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26 changes: 22 additions & 4 deletions Lib/test/test_grammar.py
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Original file line number Diff line number Diff line change
Expand Up @@ -1275,6 +1275,9 @@ def test_assert(self):
assert 1, 1
assert lambda x:x
assert 1, lambda x:x+1
assert (1, "Oh no")
assert (1,
"Oh no")

try:
assert True
Expand Down Expand Up @@ -1304,12 +1307,27 @@ def test_assert_failures(self):
else:
self.fail("AssertionError not raised by 'assert False'")

try:
assert (0, "msg")
except AssertionError as e:
self.assertEqual(e.args[0], "msg")
else:
self.fail("AssertionError not raised by assert 0")

try:
assert (0,
"msg")
except AssertionError as e:
self.assertEqual(e.args[0], "msg")
else:
self.fail("AssertionError not raised by assert 0")

def test_assert_syntax_warnings(self):
# Ensure that we warn users if they provide a non-zero length tuple as
# the assertion test.
self.check_syntax_warning('assert(x, "msg")',
self.check_syntax_warning('assert(x, y, "msg")',
'assertion is always true')
self.check_syntax_warning('assert(False, "msg")',
self.check_syntax_warning('assert(False, 2, "msg")',
'assertion is always true')
self.check_syntax_warning('assert(False,)',
'assertion is always true')
Expand All @@ -1329,9 +1347,9 @@ def test_assert_warning_promotes_to_syntax_error(self):
except SyntaxError:
self.fail('SyntaxError incorrectly raised for \'assert x, "msg"\'')
with self.assertRaises(SyntaxError):
compile('assert(x, "msg")', '<testcase>', 'exec')
compile('assert(x, "msg", 3)', '<testcase>', 'exec')
with self.assertRaises(SyntaxError):
compile('assert(False, "msg")', '<testcase>', 'exec')
compile('assert(False, "msg", 4)', '<testcase>', 'exec')
with self.assertRaises(SyntaxError):
compile('assert(False,)', '<testcase>', 'exec')

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