"""This module tests SyntaxErrors. Here's an example of the sort of thing that is tested. >>> def f(x): ... global x Traceback (most recent call last): SyntaxError: name 'x' is parameter and global The tests are all raise SyntaxErrors. They were created by checking each C call that raises SyntaxError. There are several modules that raise these exceptions-- ast.c, compile.c, future.c, pythonrun.c, and symtable.c. The parser itself outlaws a lot of invalid syntax. None of these errors are tested here at the moment. We should add some tests; since there are infinitely many programs with invalid syntax, we would need to be judicious in selecting some. The compiler generates a synthetic module name for code executed by doctest. Since all the code comes from the same module, a suffix like [1] is appended to the module name, As a consequence, changing the order of tests in this module means renumbering all the errors after it. (Maybe we should enable the ellipsis option for these tests.) In ast.c, syntax errors are raised by calling ast_error(). Errors from set_context(): >>> obj.None = 1 Traceback (most recent call last): SyntaxError: invalid syntax >>> None = 1 Traceback (most recent call last): SyntaxError: can't assign to keyword >>> f() = 1 Traceback (most recent call last): SyntaxError: can't assign to function call >>> del f() Traceback (most recent call last): SyntaxError: can't delete function call >>> a + 1 = 2 Traceback (most recent call last): SyntaxError: can't assign to operator >>> (x for x in x) = 1 Traceback (most recent call last): SyntaxError: can't assign to generator expression >>> 1 = 1 Traceback (most recent call last): SyntaxError: can't assign to literal >>> "abc" = 1 Traceback (most recent call last): SyntaxError: can't assign to literal >>> b"" = 1 Traceback (most recent call last): SyntaxError: can't assign to literal >>> `1` = 1 Traceback (most recent call last): SyntaxError: invalid syntax If the left-hand side of an assignment is a list or tuple, an illegal expression inside that contain should still cause a syntax error. This test just checks a couple of cases rather than enumerating all of them. >>> (a, "b", c) = (1, 2, 3) Traceback (most recent call last): SyntaxError: can't assign to literal >>> [a, b, c + 1] = [1, 2, 3] Traceback (most recent call last): SyntaxError: can't assign to operator >>> a if 1 else b = 1 Traceback (most recent call last): SyntaxError: can't assign to conditional expression From compiler_complex_args(): >>> def f(None=1): ... pass Traceback (most recent call last): SyntaxError: invalid syntax From ast_for_arguments(): >>> def f(x, y=1, z): ... pass Traceback (most recent call last): SyntaxError: non-default argument follows default argument >>> def f(x, None): ... pass Traceback (most recent call last): SyntaxError: invalid syntax >>> def f(*None): ... pass Traceback (most recent call last): SyntaxError: invalid syntax >>> def f(**None): ... pass Traceback (most recent call last): SyntaxError: invalid syntax From ast_for_funcdef(): >>> def None(x): ... pass Traceback (most recent call last): SyntaxError: invalid syntax From ast_for_call(): >>> def f(it, *varargs): ... return list(it) >>> L = range(10) >>> f(x for x in L) [0, 1, 2, 3, 4, 5, 6, 7, 8, 9] >>> f(x for x in L, 1) Traceback (most recent call last): SyntaxError: Generator expression must be parenthesized if not sole argument >>> f(x for x in L, y for y in L) Traceback (most recent call last): SyntaxError: Generator expression must be parenthesized if not sole argument >>> f((x for x in L), 1) [0, 1, 2, 3, 4, 5, 6, 7, 8, 9] >>> def g(*args, **kwargs): ... print(args, sorted(kwargs.items())) >>> g(0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, ... 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, ... 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, ... 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, ... 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, ... 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, ... 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121, ... 122, 123, 124, 125, 126, 127, 128, 129, 130, 131, 132, 133, 134, 135, ... 136, 137, 138, 139, 140, 141, 142, 143, 144, 145, 146, 147, 148, 149, ... 150, 151, 152, 153, 154, 155, 156, 157, 158, 159, 160, 161, 162, 163, ... 164, 165, 166, 167, 168, 169, 170, 171, 172, 173, 174, 175, 176, 177, ... 178, 179, 180, 181, 182, 183, 184, 185, 186, 187, 188, 189, 190, 191, ... 192, 193, 194, 195, 196, 197, 198, 199, 200, 201, 202, 203, 204, 205, ... 206, 207, 208, 209, 210, 211, 212, 213, 214, 215, 216, 217, 218, 219, ... 220, 221, 222, 223, 224, 225, 226, 227, 228, 229, 230, 231, 232, 233, ... 234, 235, 236, 237, 238, 239, 240, 241, 242, 243, 244, 245, 246, 247, ... 248, 249, 250, 251, 252, 253, 254, 255, 256, 257, 258, 259, 260, 261, ... 262, 263, 264, 265, 266, 267, 268, 269, 270, 271, 272, 273, 274, 275, ... 276, 277, 278, 279, 280, 281, 282, 283, 284, 285, 286, 287, 288, 289, ... 290, 291, 292, 293, 294, 295, 296, 297, 298, 299) # doctest: +ELLIPSIS (0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, ..., 297, 298, 299) [] >>> g(a000=0, a001=1, a002=2, a003=3, a004=4, a005=5, a006=6, a007=7, a008=8, ... a009=9, a010=10, a011=11, a012=12, a013=13, a014=14, a015=15, a016=16, ... a017=17, a018=18, a019=19, a020=20, a021=21, a022=22, a023=23, a024=24, ... a025=25, a026=26, a027=27, a028=28, a029=29, a030=30, a031=31, a032=32, ... a033=33, a034=34, a035=35, a036=36, a037=37, a038=38, a039=39, a040=40, ... a041=41, a042=42, a043=43, a044=44, a045=45, a046=46, a047=47, a048=48, ... a049=49, a050=50, a051=51, a052=52, a053=53, a054=54, a055=55, a056=56, ... a057=57, a058=58, a059=59, a060=60, a061=61, a062=62, a063=63, a064=64, ... a065=65, a066=66, a067=67, a068=68, a069=69, a070=70, a071=71, a072=72, ... a073=73, a074=74, a075=75, a076=76, a077=77, a078=78, a079=79, a080=80, ... a081=81, a082=82, a083=83, a084=84, a085=85, a086=86, a087=87, a088=88, ... a089=89, a090=90, a091=91, a092=92, a093=93, a094=94, a095=95, a096=96, ... a097=97, a098=98, a099=99, a100=100, a101=101, a102=102, a103=103, ... a104=104, a105=105, a106=106, a107=107, a108=108, a109=109, a110=110, ... a111=111, a112=112, a113=113, a114=114, a115=115, a116=116, a117=117, ... a118=118, a119=119, a120=120, a121=121, a122=122, a123=123, a124=124, ... a125=125, a126=126, a127=127, a128=128, a129=129, a130=130, a131=131, ... a132=132, a133=133, a134=134, a135=135, a136=136, a137=137, a138=138, ... a139=139, a140=140, a141=141, a142=142, a143=143, a144=144, a145=145, ... a146=146, a147=147, a148=148, a149=149, a150=150, a151=151, a152=152, ... a153=153, a154=154, a155=155, a156=156, a157=157, a158=158, a159=159, ... a160=160, a161=161, a162=162, a163=163, a164=164, a165=165, a166=166, ... a167=167, a168=168, a169=169, a170=170, a171=171, a172=172, a173=173, ... a174=174, a175=175, a176=176, a177=177, a178=178, a179=179, a180=180, ... a181=181, a182=182, a183=183, a184=184, a185=185, a186=186, a187=187, ... a188=188, a189=189, a190=190, a191=191, a192=192, a193=193, a194=194, ... a195=195, a196=196, a197=197, a198=198, a199=199, a200=200, a201=201, ... a202=202, a203=203, a204=204, a205=205, a206=206, a207=207, a208=208, ... a209=209, a210=210, a211=211, a212=212, a213=213, a214=214, a215=215, ... a216=216, a217=217, a218=218, a219=219, a220=220, a221=221, a222=222, ... a223=223, a224=224, a225=225, a226=226, a227=227, a228=228, a229=229, ... a230=230, a231=231, a232=232, a233=233, a234=234, a235=235, a236=236, ... a237=237, a238=238, a239=239, a240=240, a241=241, a242=242, a243=243, ... a244=244, a245=245, a246=246, a247=247, a248=248, a249=249, a250=250, ... a251=251, a252=252, a253=253, a254=254, a255=255, a256=256, a257=257, ... a258=258, a259=259, a260=260, a261=261, a262=262, a263=263, a264=264, ... a265=265, a266=266, a267=267, a268=268, a269=269, a270=270, a271=271, ... a272=272, a273=273, a274=274, a275=275, a276=276, a277=277, a278=278, ... a279=279, a280=280, a281=281, a282=282, a283=283, a284=284, a285=285, ... a286=286, a287=287, a288=288, a289=289, a290=290, a291=291, a292=292, ... a293=293, a294=294, a295=295, a296=296, a297=297, a298=298, a299=299) ... # doctest: +ELLIPSIS () [('a000', 0), ('a001', 1), ('a002', 2), ..., ('a298', 298), ('a299', 299)] >>> class C: ... def meth(self, *args): ... return args >>> obj = C() >>> obj.meth( ... 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, ... 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, ... 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, ... 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, ... 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, ... 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, ... 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121, ... 122, 123, 124, 125, 126, 127, 128, 129, 130, 131, 132, 133, 134, 135, ... 136, 137, 138, 139, 140, 141, 142, 143, 144, 145, 146, 147, 148, 149, ... 150, 151, 152, 153, 154, 155, 156, 157, 158, 159, 160, 161, 162, 163, ... 164, 165, 166, 167, 168, 169, 170, 171, 172, 173, 174, 175, 176, 177, ... 178, 179, 180, 181, 182, 183, 184, 185, 186, 187, 188, 189, 190, 191, ... 192, 193, 194, 195, 196, 197, 198, 199, 200, 201, 202, 203, 204, 205, ... 206, 207, 208, 209, 210, 211, 212, 213, 214, 215, 216, 217, 218, 219, ... 220, 221, 222, 223, 224, 225, 226, 227, 228, 229, 230, 231, 232, 233, ... 234, 235, 236, 237, 238, 239, 240, 241, 242, 243, 244, 245, 246, 247, ... 248, 249, 250, 251, 252, 253, 254, 255, 256, 257, 258, 259, 260, 261, ... 262, 263, 264, 265, 266, 267, 268, 269, 270, 271, 272, 273, 274, 275, ... 276, 277, 278, 279, 280, 281, 282, 283, 284, 285, 286, 287, 288, 289, ... 290, 291, 292, 293, 294, 295, 296, 297, 298, 299) # doctest: +ELLIPSIS (0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, ..., 297, 298, 299) >>> f(lambda x: x[0] = 3) Traceback (most recent call last): SyntaxError: lambda cannot contain assignment The grammar accepts any test (basically, any expression) in the keyword slot of a call site. Test a few different options. >>> f(x()=2) Traceback (most recent call last): SyntaxError: keyword can't be an expression >>> f(a or b=1) Traceback (most recent call last): SyntaxError: keyword can't be an expression >>> f(x.y=1) Traceback (most recent call last): SyntaxError: keyword can't be an expression More set_context(): >>> (x for x in x) += 1 Traceback (most recent call last): SyntaxError: can't assign to generator expression >>> None += 1 Traceback (most recent call last): SyntaxError: can't assign to keyword >>> f() += 1 Traceback (most recent call last): SyntaxError: can't assign to function call Test continue in finally in weird combinations. continue in for loop under finally should be ok. >>> def test(): ... try: ... pass ... finally: ... for abc in range(10): ... continue ... print(abc) >>> test() 9 Start simple, a continue in a finally should not be allowed. >>> def test(): ... for abc in range(10): ... try: ... pass ... finally: ... continue Traceback (most recent call last): ... SyntaxError: 'continue' not supported inside 'finally' clause This is essentially a continue in a finally which should not be allowed. >>> def test(): ... for abc in range(10): ... try: ... pass ... finally: ... try: ... continue ... except: ... pass Traceback (most recent call last): ... SyntaxError: 'continue' not supported inside 'finally' clause >>> def foo(): ... try: ... pass ... finally: ... continue Traceback (most recent call last): ... SyntaxError: 'continue' not supported inside 'finally' clause >>> def foo(): ... for a in (): ... try: ... pass ... finally: ... continue Traceback (most recent call last): ... SyntaxError: 'continue' not supported inside 'finally' clause >>> def foo(): ... for a in (): ... try: ... pass ... finally: ... try: ... continue ... finally: ... pass Traceback (most recent call last): ... SyntaxError: 'continue' not supported inside 'finally' clause >>> def foo(): ... for a in (): ... try: pass ... finally: ... try: ... pass ... except: ... continue Traceback (most recent call last): ... SyntaxError: 'continue' not supported inside 'finally' clause There is one test for a break that is not in a loop. The compiler uses a single data structure to keep track of try-finally and loops, so we need to be sure that a break is actually inside a loop. If it isn't, there should be a syntax error. >>> try: ... print(1) ... break ... print(2) ... finally: ... print(3) Traceback (most recent call last): ... SyntaxError: 'break' outside loop This raises a SyntaxError, it used to raise a SystemError. Context for this change can be found on issue #27514 In 2.5 there was a missing exception and an assert was triggered in a debug build. The number of blocks must be greater than CO_MAXBLOCKS. SF #1565514 >>> while 1: ... while 2: ... while 3: ... while 4: ... while 5: ... while 6: ... while 8: ... while 9: ... while 10: ... while 11: ... while 12: ... while 13: ... while 14: ... while 15: ... while 16: ... while 17: ... while 18: ... while 19: ... while 20: ... while 21: ... while 22: ... break Traceback (most recent call last): ... SyntaxError: too many statically nested blocks Misuse of the nonlocal and global statement can lead to a few unique syntax errors. >>> def f(): ... x = 1 ... global x Traceback (most recent call last): ... SyntaxError: name 'x' is assigned to before global declaration >>> def f(): ... x = 1 ... def g(): ... print(x) ... nonlocal x Traceback (most recent call last): ... SyntaxError: name 'x' is used prior to nonlocal declaration >>> def f(): ... x = 1 ... def g(): ... x = 2 ... nonlocal x Traceback (most recent call last): ... SyntaxError: name 'x' is assigned to before nonlocal declaration >>> def f(x): ... nonlocal x Traceback (most recent call last): ... SyntaxError: name 'x' is parameter and nonlocal >>> def f(): ... global x ... nonlocal x Traceback (most recent call last): ... SyntaxError: name 'x' is nonlocal and global >>> def f(): ... nonlocal x Traceback (most recent call last): ... SyntaxError: no binding for nonlocal 'x' found From SF bug #1705365 >>> nonlocal x Traceback (most recent call last): ... SyntaxError: nonlocal declaration not allowed at module level From https://bugs.python.org/issue25973 >>> class A: ... def f(self): ... nonlocal __x Traceback (most recent call last): ... SyntaxError: no binding for nonlocal '_A__x' found This tests assignment-context; there was a bug in Python 2.5 where compiling a complex 'if' (one with 'elif') would fail to notice an invalid suite, leading to spurious errors. >>> if 1: ... x() = 1 ... elif 1: ... pass Traceback (most recent call last): ... SyntaxError: can't assign to function call >>> if 1: ... pass ... elif 1: ... x() = 1 Traceback (most recent call last): ... SyntaxError: can't assign to function call >>> if 1: ... x() = 1 ... elif 1: ... pass ... else: ... pass Traceback (most recent call last): ... SyntaxError: can't assign to function call >>> if 1: ... pass ... elif 1: ... x() = 1 ... else: ... pass Traceback (most recent call last): ... SyntaxError: can't assign to function call >>> if 1: ... pass ... elif 1: ... pass ... else: ... x() = 1 Traceback (most recent call last): ... SyntaxError: can't assign to function call Make sure that the old "raise X, Y[, Z]" form is gone: >>> raise X, Y Traceback (most recent call last): ... SyntaxError: invalid syntax >>> raise X, Y, Z Traceback (most recent call last): ... SyntaxError: invalid syntax >>> f(a=23, a=234) Traceback (most recent call last): ... SyntaxError: keyword argument repeated >>> {1, 2, 3} = 42 Traceback (most recent call last): SyntaxError: can't assign to literal Corner-cases that used to fail to raise the correct error: >>> def f(*, x=lambda __debug__:0): pass Traceback (most recent call last): SyntaxError: assignment to keyword >>> def f(*args:(lambda __debug__:0)): pass Traceback (most recent call last): SyntaxError: assignment to keyword >>> def f(**kwargs:(lambda __debug__:0)): pass Traceback (most recent call last): SyntaxError: assignment to keyword >>> with (lambda *:0): pass Traceback (most recent call last): SyntaxError: named arguments must follow bare * Corner-cases that used to crash: >>> def f(**__debug__): pass Traceback (most recent call last): SyntaxError: assignment to keyword >>> def f(*xx, __debug__): pass Traceback (most recent call last): SyntaxError: assignment to keyword """ import re import unittest import warnings from test import support class SyntaxTestCase(unittest.TestCase): def _check_error(self, code, errtext, filename="", mode="exec", subclass=None, lineno=None, offset=None): """Check that compiling code raises SyntaxError with errtext. errtest is a regular expression that must be present in the test of the exception raised. If subclass is specified it is the expected subclass of SyntaxError (e.g. IndentationError). """ try: compile(code, filename, mode) except SyntaxError as err: if subclass and not isinstance(err, subclass): self.fail("SyntaxError is not a %s" % subclass.__name__) mo = re.search(errtext, str(err)) if mo is None: self.fail("SyntaxError did not contain '%r'" % (errtext,)) self.assertEqual(err.filename, filename) if lineno is not None: self.assertEqual(err.lineno, lineno) if offset is not None: self.assertEqual(err.offset, offset) else: self.fail("compile() did not raise SyntaxError") def test_assign_call(self): self._check_error("f() = 1", "assign") def test_assign_del(self): self._check_error("del f()", "delete") def test_global_err_then_warn(self): # Bug #763201: The SyntaxError raised for one global statement # shouldn't be clobbered by a SyntaxWarning issued for a later one. source = """if 1: def error(a): global a # SyntaxError def warning(): b = 1 global b # SyntaxWarning """ warnings.filterwarnings(action='ignore', category=SyntaxWarning) self._check_error(source, "global") warnings.filters.pop(0) def test_break_outside_loop(self): self._check_error("break", "outside loop") def test_unexpected_indent(self): self._check_error("foo()\n bar()\n", "unexpected indent", subclass=IndentationError) def test_no_indent(self): self._check_error("if 1:\nfoo()", "expected an indented block", subclass=IndentationError) def test_bad_outdent(self): self._check_error("if 1:\n foo()\n bar()", "unindent does not match .* level", subclass=IndentationError) def test_kwargs_last(self): self._check_error("int(base=10, '2')", "positional argument follows keyword argument") def test_kwargs_last2(self): self._check_error("int(**{base: 10}, '2')", "positional argument follows " "keyword argument unpacking") def test_kwargs_last3(self): self._check_error("int(**{base: 10}, *['2'])", "iterable argument unpacking follows " "keyword argument unpacking") def test_main(): support.run_unittest(SyntaxTestCase) from test import test_syntax support.run_doctest(test_syntax, verbosity=True) if __name__ == "__main__": test_main()