585 lines
20 KiB
Python
585 lines
20 KiB
Python
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import unittest
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from test.support import use_old_parser
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GLOBAL_VAR = None
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class NamedExpressionInvalidTest(unittest.TestCase):
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def test_named_expression_invalid_01(self):
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code = """x := 0"""
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with self.assertRaisesRegex(SyntaxError, "invalid syntax"):
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exec(code, {}, {})
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def test_named_expression_invalid_02(self):
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code = """x = y := 0"""
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with self.assertRaisesRegex(SyntaxError, "invalid syntax"):
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exec(code, {}, {})
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def test_named_expression_invalid_03(self):
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code = """y := f(x)"""
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with self.assertRaisesRegex(SyntaxError, "invalid syntax"):
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exec(code, {}, {})
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def test_named_expression_invalid_04(self):
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code = """y0 = y1 := f(x)"""
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with self.assertRaisesRegex(SyntaxError, "invalid syntax"):
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exec(code, {}, {})
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def test_named_expression_invalid_06(self):
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code = """((a, b) := (1, 2))"""
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with self.assertRaisesRegex(SyntaxError, "cannot use assignment expressions with tuple"):
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exec(code, {}, {})
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def test_named_expression_invalid_07(self):
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code = """def spam(a = b := 42): pass"""
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with self.assertRaisesRegex(SyntaxError, "invalid syntax"):
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exec(code, {}, {})
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def test_named_expression_invalid_08(self):
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code = """def spam(a: b := 42 = 5): pass"""
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with self.assertRaisesRegex(SyntaxError, "invalid syntax"):
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exec(code, {}, {})
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def test_named_expression_invalid_09(self):
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code = """spam(a=b := 'c')"""
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with self.assertRaisesRegex(SyntaxError, "invalid syntax"):
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exec(code, {}, {})
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def test_named_expression_invalid_10(self):
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code = """spam(x = y := f(x))"""
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with self.assertRaisesRegex(SyntaxError, "invalid syntax"):
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exec(code, {}, {})
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def test_named_expression_invalid_11(self):
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code = """spam(a=1, b := 2)"""
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with self.assertRaisesRegex(SyntaxError,
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"positional argument follows keyword argument"):
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exec(code, {}, {})
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def test_named_expression_invalid_12(self):
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code = """spam(a=1, (b := 2))"""
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with self.assertRaisesRegex(SyntaxError,
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"positional argument follows keyword argument"):
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exec(code, {}, {})
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def test_named_expression_invalid_13(self):
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code = """spam(a=1, (b := 2))"""
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with self.assertRaisesRegex(SyntaxError,
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"positional argument follows keyword argument"):
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exec(code, {}, {})
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def test_named_expression_invalid_14(self):
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code = """(x := lambda: y := 1)"""
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with self.assertRaisesRegex(SyntaxError, "invalid syntax"):
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exec(code, {}, {})
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def test_named_expression_invalid_15(self):
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code = """(lambda: x := 1)"""
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with self.assertRaisesRegex(SyntaxError,
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"cannot use assignment expressions with lambda"):
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exec(code, {}, {})
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def test_named_expression_invalid_16(self):
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code = "[i + 1 for i in i := [1,2]]"
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with self.assertRaisesRegex(SyntaxError, "invalid syntax"):
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exec(code, {}, {})
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def test_named_expression_invalid_17(self):
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code = "[i := 0, j := 1 for i, j in [(1, 2), (3, 4)]]"
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with self.assertRaisesRegex(SyntaxError, "invalid syntax"):
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exec(code, {}, {})
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def test_named_expression_invalid_in_class_body(self):
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code = """class Foo():
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[(42, 1 + ((( j := i )))) for i in range(5)]
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"""
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with self.assertRaisesRegex(SyntaxError,
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"assignment expression within a comprehension cannot be used in a class body"):
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exec(code, {}, {})
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def test_named_expression_invalid_rebinding_list_comprehension_iteration_variable(self):
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cases = [
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("Local reuse", 'i', "[i := 0 for i in range(5)]"),
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("Nested reuse", 'j', "[[(j := 0) for i in range(5)] for j in range(5)]"),
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("Reuse inner loop target", 'j', "[(j := 0) for i in range(5) for j in range(5)]"),
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("Unpacking reuse", 'i', "[i := 0 for i, j in [(0, 1)]]"),
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("Reuse in loop condition", 'i', "[i+1 for i in range(5) if (i := 0)]"),
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("Unreachable reuse", 'i', "[False or (i:=0) for i in range(5)]"),
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("Unreachable nested reuse", 'i',
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"[(i, j) for i in range(5) for j in range(5) if True or (i:=10)]"),
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]
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for case, target, code in cases:
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msg = f"assignment expression cannot rebind comprehension iteration variable '{target}'"
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with self.subTest(case=case):
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with self.assertRaisesRegex(SyntaxError, msg):
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exec(code, {}, {})
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def test_named_expression_invalid_rebinding_list_comprehension_inner_loop(self):
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cases = [
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("Inner reuse", 'j', "[i for i in range(5) if (j := 0) for j in range(5)]"),
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("Inner unpacking reuse", 'j', "[i for i in range(5) if (j := 0) for j, k in [(0, 1)]]"),
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]
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for case, target, code in cases:
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msg = f"comprehension inner loop cannot rebind assignment expression target '{target}'"
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with self.subTest(case=case):
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with self.assertRaisesRegex(SyntaxError, msg):
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exec(code, {}) # Module scope
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with self.assertRaisesRegex(SyntaxError, msg):
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exec(code, {}, {}) # Class scope
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with self.assertRaisesRegex(SyntaxError, msg):
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exec(f"lambda: {code}", {}) # Function scope
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def test_named_expression_invalid_list_comprehension_iterable_expression(self):
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cases = [
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("Top level", "[i for i in (i := range(5))]"),
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("Inside tuple", "[i for i in (2, 3, i := range(5))]"),
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("Inside list", "[i for i in [2, 3, i := range(5)]]"),
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("Different name", "[i for i in (j := range(5))]"),
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("Lambda expression", "[i for i in (lambda:(j := range(5)))()]"),
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("Inner loop", "[i for i in range(5) for j in (i := range(5))]"),
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("Nested comprehension", "[i for i in [j for j in (k := range(5))]]"),
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("Nested comprehension condition", "[i for i in [j for j in range(5) if (j := True)]]"),
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("Nested comprehension body", "[i for i in [(j := True) for j in range(5)]]"),
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]
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msg = "assignment expression cannot be used in a comprehension iterable expression"
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for case, code in cases:
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with self.subTest(case=case):
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with self.assertRaisesRegex(SyntaxError, msg):
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exec(code, {}) # Module scope
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with self.assertRaisesRegex(SyntaxError, msg):
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exec(code, {}, {}) # Class scope
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with self.assertRaisesRegex(SyntaxError, msg):
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exec(f"lambda: {code}", {}) # Function scope
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@unittest.skipIf(use_old_parser(), "Old parser does not support walruses in set comprehensions")
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def test_named_expression_invalid_rebinding_set_comprehension_iteration_variable(self):
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cases = [
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("Local reuse", 'i', "{i := 0 for i in range(5)}"),
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("Nested reuse", 'j', "{{(j := 0) for i in range(5)} for j in range(5)}"),
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("Reuse inner loop target", 'j', "{(j := 0) for i in range(5) for j in range(5)}"),
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("Unpacking reuse", 'i', "{i := 0 for i, j in {(0, 1)}}"),
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("Reuse in loop condition", 'i', "{i+1 for i in range(5) if (i := 0)}"),
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("Unreachable reuse", 'i', "{False or (i:=0) for i in range(5)}"),
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("Unreachable nested reuse", 'i',
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"{(i, j) for i in range(5) for j in range(5) if True or (i:=10)}"),
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]
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for case, target, code in cases:
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msg = f"assignment expression cannot rebind comprehension iteration variable '{target}'"
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with self.subTest(case=case):
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with self.assertRaisesRegex(SyntaxError, msg):
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exec(code, {}, {})
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def test_named_expression_invalid_rebinding_set_comprehension_inner_loop(self):
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cases = [
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("Inner reuse", 'j', "{i for i in range(5) if (j := 0) for j in range(5)}"),
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("Inner unpacking reuse", 'j', "{i for i in range(5) if (j := 0) for j, k in {(0, 1)}}"),
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]
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for case, target, code in cases:
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msg = f"comprehension inner loop cannot rebind assignment expression target '{target}'"
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with self.subTest(case=case):
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with self.assertRaisesRegex(SyntaxError, msg):
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exec(code, {}) # Module scope
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with self.assertRaisesRegex(SyntaxError, msg):
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exec(code, {}, {}) # Class scope
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with self.assertRaisesRegex(SyntaxError, msg):
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exec(f"lambda: {code}", {}) # Function scope
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@unittest.skipIf(use_old_parser(), "Old parser does not support walruses in set comprehensions")
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def test_named_expression_invalid_set_comprehension_iterable_expression(self):
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cases = [
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("Top level", "{i for i in (i := range(5))}"),
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("Inside tuple", "{i for i in (2, 3, i := range(5))}"),
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("Inside list", "{i for i in {2, 3, i := range(5)}}"),
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("Different name", "{i for i in (j := range(5))}"),
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("Lambda expression", "{i for i in (lambda:(j := range(5)))()}"),
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("Inner loop", "{i for i in range(5) for j in (i := range(5))}"),
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("Nested comprehension", "{i for i in {j for j in (k := range(5))}}"),
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("Nested comprehension condition", "{i for i in {j for j in range(5) if (j := True)}}"),
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("Nested comprehension body", "{i for i in {(j := True) for j in range(5)}}"),
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]
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msg = "assignment expression cannot be used in a comprehension iterable expression"
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for case, code in cases:
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with self.subTest(case=case):
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with self.assertRaisesRegex(SyntaxError, msg):
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exec(code, {}) # Module scope
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with self.assertRaisesRegex(SyntaxError, msg):
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exec(code, {}, {}) # Class scope
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with self.assertRaisesRegex(SyntaxError, msg):
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exec(f"lambda: {code}", {}) # Function scope
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class NamedExpressionAssignmentTest(unittest.TestCase):
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def test_named_expression_assignment_01(self):
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(a := 10)
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self.assertEqual(a, 10)
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def test_named_expression_assignment_02(self):
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a = 20
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(a := a)
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self.assertEqual(a, 20)
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def test_named_expression_assignment_03(self):
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(total := 1 + 2)
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self.assertEqual(total, 3)
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def test_named_expression_assignment_04(self):
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(info := (1, 2, 3))
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self.assertEqual(info, (1, 2, 3))
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def test_named_expression_assignment_05(self):
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(x := 1, 2)
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self.assertEqual(x, 1)
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def test_named_expression_assignment_06(self):
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(z := (y := (x := 0)))
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self.assertEqual(x, 0)
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self.assertEqual(y, 0)
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self.assertEqual(z, 0)
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def test_named_expression_assignment_07(self):
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(loc := (1, 2))
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self.assertEqual(loc, (1, 2))
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def test_named_expression_assignment_08(self):
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if spam := "eggs":
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self.assertEqual(spam, "eggs")
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else: self.fail("variable was not assigned using named expression")
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def test_named_expression_assignment_09(self):
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if True and (spam := True):
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self.assertTrue(spam)
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else: self.fail("variable was not assigned using named expression")
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def test_named_expression_assignment_10(self):
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if (match := 10) == 10:
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pass
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else: self.fail("variable was not assigned using named expression")
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def test_named_expression_assignment_11(self):
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def spam(a):
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return a
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input_data = [1, 2, 3]
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res = [(x, y, x/y) for x in input_data if (y := spam(x)) > 0]
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self.assertEqual(res, [(1, 1, 1.0), (2, 2, 1.0), (3, 3, 1.0)])
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def test_named_expression_assignment_12(self):
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def spam(a):
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return a
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res = [[y := spam(x), x/y] for x in range(1, 5)]
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self.assertEqual(res, [[1, 1.0], [2, 1.0], [3, 1.0], [4, 1.0]])
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def test_named_expression_assignment_13(self):
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length = len(lines := [1, 2])
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self.assertEqual(length, 2)
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self.assertEqual(lines, [1,2])
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def test_named_expression_assignment_14(self):
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"""
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Where all variables are positive integers, and a is at least as large
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as the n'th root of x, this algorithm returns the floor of the n'th
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root of x (and roughly doubling the number of accurate bits per
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iteration):
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"""
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a = 9
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n = 2
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x = 3
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while a > (d := x // a**(n-1)):
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a = ((n-1)*a + d) // n
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self.assertEqual(a, 1)
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def test_named_expression_assignment_15(self):
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while a := False:
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pass # This will not run
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self.assertEqual(a, False)
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def test_named_expression_assignment_16(self):
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a, b = 1, 2
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fib = {(c := a): (a := b) + (b := a + c) - b for __ in range(6)}
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self.assertEqual(fib, {1: 2, 2: 3, 3: 5, 5: 8, 8: 13, 13: 21})
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class NamedExpressionScopeTest(unittest.TestCase):
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def test_named_expression_scope_01(self):
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code = """def spam():
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(a := 5)
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print(a)"""
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with self.assertRaisesRegex(NameError, "name 'a' is not defined"):
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exec(code, {}, {})
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def test_named_expression_scope_02(self):
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total = 0
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|
partial_sums = [total := total + v for v in range(5)]
|
||
|
|
|
||
|
|
self.assertEqual(partial_sums, [0, 1, 3, 6, 10])
|
||
|
|
self.assertEqual(total, 10)
|
||
|
|
|
||
|
|
def test_named_expression_scope_03(self):
|
||
|
|
containsOne = any((lastNum := num) == 1 for num in [1, 2, 3])
|
||
|
|
|
||
|
|
self.assertTrue(containsOne)
|
||
|
|
self.assertEqual(lastNum, 1)
|
||
|
|
|
||
|
|
def test_named_expression_scope_04(self):
|
||
|
|
def spam(a):
|
||
|
|
return a
|
||
|
|
res = [[y := spam(x), x/y] for x in range(1, 5)]
|
||
|
|
|
||
|
|
self.assertEqual(y, 4)
|
||
|
|
|
||
|
|
def test_named_expression_scope_05(self):
|
||
|
|
def spam(a):
|
||
|
|
return a
|
||
|
|
input_data = [1, 2, 3]
|
||
|
|
res = [(x, y, x/y) for x in input_data if (y := spam(x)) > 0]
|
||
|
|
|
||
|
|
self.assertEqual(res, [(1, 1, 1.0), (2, 2, 1.0), (3, 3, 1.0)])
|
||
|
|
self.assertEqual(y, 3)
|
||
|
|
|
||
|
|
def test_named_expression_scope_06(self):
|
||
|
|
res = [[spam := i for i in range(3)] for j in range(2)]
|
||
|
|
|
||
|
|
self.assertEqual(res, [[0, 1, 2], [0, 1, 2]])
|
||
|
|
self.assertEqual(spam, 2)
|
||
|
|
|
||
|
|
def test_named_expression_scope_07(self):
|
||
|
|
len(lines := [1, 2])
|
||
|
|
|
||
|
|
self.assertEqual(lines, [1, 2])
|
||
|
|
|
||
|
|
def test_named_expression_scope_08(self):
|
||
|
|
def spam(a):
|
||
|
|
return a
|
||
|
|
|
||
|
|
def eggs(b):
|
||
|
|
return b * 2
|
||
|
|
|
||
|
|
res = [spam(a := eggs(b := h)) for h in range(2)]
|
||
|
|
|
||
|
|
self.assertEqual(res, [0, 2])
|
||
|
|
self.assertEqual(a, 2)
|
||
|
|
self.assertEqual(b, 1)
|
||
|
|
|
||
|
|
def test_named_expression_scope_09(self):
|
||
|
|
def spam(a):
|
||
|
|
return a
|
||
|
|
|
||
|
|
def eggs(b):
|
||
|
|
return b * 2
|
||
|
|
|
||
|
|
res = [spam(a := eggs(a := h)) for h in range(2)]
|
||
|
|
|
||
|
|
self.assertEqual(res, [0, 2])
|
||
|
|
self.assertEqual(a, 2)
|
||
|
|
|
||
|
|
def test_named_expression_scope_10(self):
|
||
|
|
res = [b := [a := 1 for i in range(2)] for j in range(2)]
|
||
|
|
|
||
|
|
self.assertEqual(res, [[1, 1], [1, 1]])
|
||
|
|
self.assertEqual(a, 1)
|
||
|
|
self.assertEqual(b, [1, 1])
|
||
|
|
|
||
|
|
def test_named_expression_scope_11(self):
|
||
|
|
res = [j := i for i in range(5)]
|
||
|
|
|
||
|
|
self.assertEqual(res, [0, 1, 2, 3, 4])
|
||
|
|
self.assertEqual(j, 4)
|
||
|
|
|
||
|
|
def test_named_expression_scope_17(self):
|
||
|
|
b = 0
|
||
|
|
res = [b := i + b for i in range(5)]
|
||
|
|
|
||
|
|
self.assertEqual(res, [0, 1, 3, 6, 10])
|
||
|
|
self.assertEqual(b, 10)
|
||
|
|
|
||
|
|
def test_named_expression_scope_18(self):
|
||
|
|
def spam(a):
|
||
|
|
return a
|
||
|
|
|
||
|
|
res = spam(b := 2)
|
||
|
|
|
||
|
|
self.assertEqual(res, 2)
|
||
|
|
self.assertEqual(b, 2)
|
||
|
|
|
||
|
|
def test_named_expression_scope_19(self):
|
||
|
|
def spam(a):
|
||
|
|
return a
|
||
|
|
|
||
|
|
res = spam((b := 2))
|
||
|
|
|
||
|
|
self.assertEqual(res, 2)
|
||
|
|
self.assertEqual(b, 2)
|
||
|
|
|
||
|
|
def test_named_expression_scope_20(self):
|
||
|
|
def spam(a):
|
||
|
|
return a
|
||
|
|
|
||
|
|
res = spam(a=(b := 2))
|
||
|
|
|
||
|
|
self.assertEqual(res, 2)
|
||
|
|
self.assertEqual(b, 2)
|
||
|
|
|
||
|
|
def test_named_expression_scope_21(self):
|
||
|
|
def spam(a, b):
|
||
|
|
return a + b
|
||
|
|
|
||
|
|
res = spam(c := 2, b=1)
|
||
|
|
|
||
|
|
self.assertEqual(res, 3)
|
||
|
|
self.assertEqual(c, 2)
|
||
|
|
|
||
|
|
def test_named_expression_scope_22(self):
|
||
|
|
def spam(a, b):
|
||
|
|
return a + b
|
||
|
|
|
||
|
|
res = spam((c := 2), b=1)
|
||
|
|
|
||
|
|
self.assertEqual(res, 3)
|
||
|
|
self.assertEqual(c, 2)
|
||
|
|
|
||
|
|
def test_named_expression_scope_23(self):
|
||
|
|
def spam(a, b):
|
||
|
|
return a + b
|
||
|
|
|
||
|
|
res = spam(b=(c := 2), a=1)
|
||
|
|
|
||
|
|
self.assertEqual(res, 3)
|
||
|
|
self.assertEqual(c, 2)
|
||
|
|
|
||
|
|
def test_named_expression_scope_24(self):
|
||
|
|
a = 10
|
||
|
|
def spam():
|
||
|
|
nonlocal a
|
||
|
|
(a := 20)
|
||
|
|
spam()
|
||
|
|
|
||
|
|
self.assertEqual(a, 20)
|
||
|
|
|
||
|
|
def test_named_expression_scope_25(self):
|
||
|
|
ns = {}
|
||
|
|
code = """a = 10
|
||
|
|
def spam():
|
||
|
|
global a
|
||
|
|
(a := 20)
|
||
|
|
spam()"""
|
||
|
|
|
||
|
|
exec(code, ns, {})
|
||
|
|
|
||
|
|
self.assertEqual(ns["a"], 20)
|
||
|
|
|
||
|
|
def test_named_expression_variable_reuse_in_comprehensions(self):
|
||
|
|
# The compiler is expected to raise syntax error for comprehension
|
||
|
|
# iteration variables, but should be fine with rebinding of other
|
||
|
|
# names (e.g. globals, nonlocals, other assignment expressions)
|
||
|
|
|
||
|
|
# The cases are all defined to produce the same expected result
|
||
|
|
# Each comprehension is checked at both function scope and module scope
|
||
|
|
rebinding = "[x := i for i in range(3) if (x := i) or not x]"
|
||
|
|
filter_ref = "[x := i for i in range(3) if x or not x]"
|
||
|
|
body_ref = "[x for i in range(3) if (x := i) or not x]"
|
||
|
|
nested_ref = "[j for i in range(3) if x or not x for j in range(3) if (x := i)][:-3]"
|
||
|
|
cases = [
|
||
|
|
("Rebind global", f"x = 1; result = {rebinding}"),
|
||
|
|
("Rebind nonlocal", f"result, x = (lambda x=1: ({rebinding}, x))()"),
|
||
|
|
("Filter global", f"x = 1; result = {filter_ref}"),
|
||
|
|
("Filter nonlocal", f"result, x = (lambda x=1: ({filter_ref}, x))()"),
|
||
|
|
("Body global", f"x = 1; result = {body_ref}"),
|
||
|
|
("Body nonlocal", f"result, x = (lambda x=1: ({body_ref}, x))()"),
|
||
|
|
("Nested global", f"x = 1; result = {nested_ref}"),
|
||
|
|
("Nested nonlocal", f"result, x = (lambda x=1: ({nested_ref}, x))()"),
|
||
|
|
]
|
||
|
|
for case, code in cases:
|
||
|
|
with self.subTest(case=case):
|
||
|
|
ns = {}
|
||
|
|
exec(code, ns)
|
||
|
|
self.assertEqual(ns["x"], 2)
|
||
|
|
self.assertEqual(ns["result"], [0, 1, 2])
|
||
|
|
|
||
|
|
def test_named_expression_global_scope(self):
|
||
|
|
sentinel = object()
|
||
|
|
global GLOBAL_VAR
|
||
|
|
def f():
|
||
|
|
global GLOBAL_VAR
|
||
|
|
[GLOBAL_VAR := sentinel for _ in range(1)]
|
||
|
|
self.assertEqual(GLOBAL_VAR, sentinel)
|
||
|
|
try:
|
||
|
|
f()
|
||
|
|
self.assertEqual(GLOBAL_VAR, sentinel)
|
||
|
|
finally:
|
||
|
|
GLOBAL_VAR = None
|
||
|
|
|
||
|
|
def test_named_expression_global_scope_no_global_keyword(self):
|
||
|
|
sentinel = object()
|
||
|
|
def f():
|
||
|
|
GLOBAL_VAR = None
|
||
|
|
[GLOBAL_VAR := sentinel for _ in range(1)]
|
||
|
|
self.assertEqual(GLOBAL_VAR, sentinel)
|
||
|
|
f()
|
||
|
|
self.assertEqual(GLOBAL_VAR, None)
|
||
|
|
|
||
|
|
def test_named_expression_nonlocal_scope(self):
|
||
|
|
sentinel = object()
|
||
|
|
def f():
|
||
|
|
nonlocal_var = None
|
||
|
|
def g():
|
||
|
|
nonlocal nonlocal_var
|
||
|
|
[nonlocal_var := sentinel for _ in range(1)]
|
||
|
|
g()
|
||
|
|
self.assertEqual(nonlocal_var, sentinel)
|
||
|
|
f()
|
||
|
|
|
||
|
|
def test_named_expression_nonlocal_scope_no_nonlocal_keyword(self):
|
||
|
|
sentinel = object()
|
||
|
|
def f():
|
||
|
|
nonlocal_var = None
|
||
|
|
def g():
|
||
|
|
[nonlocal_var := sentinel for _ in range(1)]
|
||
|
|
g()
|
||
|
|
self.assertEqual(nonlocal_var, None)
|
||
|
|
f()
|
||
|
|
|
||
|
|
def test_named_expression_scope_in_genexp(self):
|
||
|
|
a = 1
|
||
|
|
b = [1, 2, 3, 4]
|
||
|
|
genexp = (c := i + a for i in b)
|
||
|
|
|
||
|
|
self.assertNotIn("c", locals())
|
||
|
|
for idx, elem in enumerate(genexp):
|
||
|
|
self.assertEqual(elem, b[idx] + a)
|
||
|
|
|
||
|
|
|
||
|
|
if __name__ == "__main__":
|
||
|
|
unittest.main()
|