From 23f159ae711d84177e8ce34cd9a6c8a762de64ac Mon Sep 17 00:00:00 2001 From: sobolevn Date: Mon, 2 Sep 2024 14:11:44 +0300 Subject: [PATCH] gh-123562: Improve `SyntaxError` message for `case ... as a.b` (#123563) --- Grammar/python.gram | 4 +- Lib/test/test_patma.py | 7 ++++ Lib/test/test_syntax.py | 42 ++++++++++++++++++- ...-09-01-12-08-39.gh-issue-123562.aJPKVu.rst | 2 + Parser/parser.c | 14 +++---- 5 files changed, 59 insertions(+), 10 deletions(-) create mode 100644 Misc/NEWS.d/next/Core_and_Builtins/2024-09-01-12-08-39.gh-issue-123562.aJPKVu.rst diff --git a/Grammar/python.gram b/Grammar/python.gram index 431bb90830a..e9a8c69c4fa 100644 --- a/Grammar/python.gram +++ b/Grammar/python.gram @@ -1375,7 +1375,9 @@ invalid_case_block: RAISE_INDENTATION_ERROR("expected an indented block after 'case' statement on line %d", a->lineno) } invalid_as_pattern: | or_pattern 'as' a="_" { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "cannot use '_' as a target") } - | or_pattern 'as' !NAME a=expression { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "invalid pattern target") } + | or_pattern 'as' a=expression { + RAISE_SYNTAX_ERROR_KNOWN_LOCATION( + a, "cannot use %s as pattern target", _PyPegen_get_expr_name(a)) } invalid_class_pattern: | name_or_attr '(' a=invalid_class_argument_pattern { RAISE_SYNTAX_ERROR_KNOWN_RANGE( PyPegen_first_item(a, pattern_ty), diff --git a/Lib/test/test_patma.py b/Lib/test/test_patma.py index 8325b83a593..dae6d898964 100644 --- a/Lib/test/test_patma.py +++ b/Lib/test/test_patma.py @@ -3015,6 +3015,13 @@ class TestSyntaxErrors(unittest.TestCase): pass """) + def test_multiple_assignments_to_name_in_pattern_6(self): + self.assert_syntax_error(""" + match ...: + case a as a + 1: # NAME and expression with no () + pass + """) + def test_multiple_starred_names_in_sequence_pattern_0(self): self.assert_syntax_error(""" match ...: diff --git a/Lib/test/test_syntax.py b/Lib/test/test_syntax.py index 406ea2118f2..132e2b83962 100644 --- a/Lib/test/test_syntax.py +++ b/Lib/test/test_syntax.py @@ -1932,7 +1932,31 @@ Corner-cases that used to crash: ... case 42 as 1+2+4: ... ... Traceback (most recent call last): - SyntaxError: invalid pattern target + SyntaxError: cannot use expression as pattern target + + >>> match ...: + ... case 42 as a.b: + ... ... + Traceback (most recent call last): + SyntaxError: cannot use attribute as pattern target + + >>> match ...: + ... case 42 as (a, b): + ... ... + Traceback (most recent call last): + SyntaxError: cannot use tuple as pattern target + + >>> match ...: + ... case 42 as (a + 1): + ... ... + Traceback (most recent call last): + SyntaxError: cannot use expression as pattern target + + >>> match ...: + ... case (32 as x) | (42 as a()): + ... ... + Traceback (most recent call last): + SyntaxError: cannot use function call as pattern target >>> match ...: ... case Foo(z=1, y=2, x): @@ -2817,6 +2841,22 @@ while 1: end_offset=22 + len("obj.attr"), ) + def test_match_stmt_invalid_as_expr(self): + self._check_error( + textwrap.dedent( + """ + match 1: + case x as obj.attr: + ... + """ + ), + errtext="cannot use attribute as pattern target", + lineno=3, + end_lineno=3, + offset=15, + end_offset=15 + len("obj.attr"), + ) + def load_tests(loader, tests, pattern): tests.addTest(doctest.DocTestSuite()) diff --git a/Misc/NEWS.d/next/Core_and_Builtins/2024-09-01-12-08-39.gh-issue-123562.aJPKVu.rst b/Misc/NEWS.d/next/Core_and_Builtins/2024-09-01-12-08-39.gh-issue-123562.aJPKVu.rst new file mode 100644 index 00000000000..10ef82c9677 --- /dev/null +++ b/Misc/NEWS.d/next/Core_and_Builtins/2024-09-01-12-08-39.gh-issue-123562.aJPKVu.rst @@ -0,0 +1,2 @@ +Improve :exc:`SyntaxError` message for using ``case ... as ...`` with not a +name. diff --git a/Parser/parser.c b/Parser/parser.c index 3c403958e65..e5567d0f63f 100644 --- a/Parser/parser.c +++ b/Parser/parser.c @@ -24005,7 +24005,7 @@ invalid_case_block_rule(Parser *p) return _res; } -// invalid_as_pattern: or_pattern 'as' "_" | or_pattern 'as' !NAME expression +// invalid_as_pattern: or_pattern 'as' "_" | or_pattern 'as' expression static void * invalid_as_pattern_rule(Parser *p) { @@ -24048,12 +24048,12 @@ invalid_as_pattern_rule(Parser *p) D(fprintf(stderr, "%*c%s invalid_as_pattern[%d-%d]: %s failed!\n", p->level, ' ', p->error_indicator ? "ERROR!" : "-", _mark, p->mark, "or_pattern 'as' \"_\"")); } - { // or_pattern 'as' !NAME expression + { // or_pattern 'as' expression if (p->error_indicator) { p->level--; return NULL; } - D(fprintf(stderr, "%*c> invalid_as_pattern[%d-%d]: %s\n", p->level, ' ', _mark, p->mark, "or_pattern 'as' !NAME expression")); + D(fprintf(stderr, "%*c> invalid_as_pattern[%d-%d]: %s\n", p->level, ' ', _mark, p->mark, "or_pattern 'as' expression")); Token * _keyword; expr_ty a; pattern_ty or_pattern_var; @@ -24062,13 +24062,11 @@ invalid_as_pattern_rule(Parser *p) && (_keyword = _PyPegen_expect_token(p, 666)) // token='as' && - _PyPegen_lookahead_with_name(0, _PyPegen_name_token, p) - && (a = expression_rule(p)) // expression ) { - D(fprintf(stderr, "%*c+ invalid_as_pattern[%d-%d]: %s succeeded!\n", p->level, ' ', _mark, p->mark, "or_pattern 'as' !NAME expression")); - _res = RAISE_SYNTAX_ERROR_KNOWN_LOCATION ( a , "invalid pattern target" ); + D(fprintf(stderr, "%*c+ invalid_as_pattern[%d-%d]: %s succeeded!\n", p->level, ' ', _mark, p->mark, "or_pattern 'as' expression")); + _res = RAISE_SYNTAX_ERROR_KNOWN_LOCATION ( a , "cannot use %s as pattern target" , _PyPegen_get_expr_name ( a ) ); if (_res == NULL && PyErr_Occurred()) { p->error_indicator = 1; p->level--; @@ -24078,7 +24076,7 @@ invalid_as_pattern_rule(Parser *p) } p->mark = _mark; D(fprintf(stderr, "%*c%s invalid_as_pattern[%d-%d]: %s failed!\n", p->level, ' ', - p->error_indicator ? "ERROR!" : "-", _mark, p->mark, "or_pattern 'as' !NAME expression")); + p->error_indicator ? "ERROR!" : "-", _mark, p->mark, "or_pattern 'as' expression")); } _res = NULL; done: