https://github.com/python/cpython/commit/2b428dadab504c9a34f445eaca8def9bcb6d73b0 commit: 2b428dadab504c9a34f445eaca8def9bcb6d73b0 branch: 3.15 author: Miss Islington (bot) <[email protected]> committer: pablogsal <[email protected]> date: 2026-09-24T23:51:39+01:00 summary:
[3.15] gh-152708: Fix AST generation asymmetry for unary positive in match statements (GH-152712) (#158079) gh-152708: Fix AST generation asymmetry for unary positive in match statements (GH-152712) (cherry picked from commit 7884f48af47f3e33640a964e55f3391698726a26) Co-authored-by: Rishit Agnihotri <[email protected]> Co-authored-by: Petr Viktorin <[email protected]> Co-authored-by: johnslavik <[email protected]> files: A Misc/NEWS.d/next/Core_and_Builtins/2026-06-30-14-50-00.gh-issue-152708.aBcDeF.rst M Grammar/python.gram M Lib/test/test_unparse.py M Parser/parser.c M Python/ast.c M Python/ast_preprocess.c diff --git a/Grammar/python.gram b/Grammar/python.gram index 036e3fc0f73a9f..c0b1d879d3c9e3 100644 --- a/Grammar/python.gram +++ b/Grammar/python.gram @@ -555,12 +555,12 @@ complex_number[expr_ty]: signed_number[expr_ty]: | NUMBER - | '+' number=NUMBER { number } + | '+' number=NUMBER { _PyAST_UnaryOp(UAdd, number, EXTRA) } | '-' number=NUMBER { _PyAST_UnaryOp(USub, number, EXTRA) } signed_real_number[expr_ty]: | real_number - | '+' real=real_number { real } + | '+' real=real_number { _PyAST_UnaryOp(UAdd, real, EXTRA) } | '-' real=real_number { _PyAST_UnaryOp(USub, real, EXTRA) } real_number[expr_ty]: diff --git a/Lib/test/test_unparse.py b/Lib/test/test_unparse.py index 28faede2e2a1a5..9bc04fc8e0affb 100644 --- a/Lib/test/test_unparse.py +++ b/Lib/test/test_unparse.py @@ -693,6 +693,24 @@ def test_unparse_interactive_integrity_3(self): self.check_src_roundtrip(src, out, mode='single') + @test.support.subTests('case', [ + "case 'a string':", + "case True:", + "case _:", + "case [*_]:", + "case tuple():", + "case cls(arg, more=arg2):", + "case tuple() | list():", + "case [tuple() as obj, _, {'a': a, **more}]:", + "case -2:", + "case +2:", + "case 2 + 3j:", + "case +2 - 3j:", + ]) + def test_unparse_match(self, case): + src = 'match x:\n ' + case + '\n pass' + self.check_src_roundtrip(src) + class CosmeticTestCase(ASTTestCase): """Test if there are cosmetic issues caused by unnecessary additions""" diff --git a/Misc/NEWS.d/next/Core_and_Builtins/2026-06-30-14-50-00.gh-issue-152708.aBcDeF.rst b/Misc/NEWS.d/next/Core_and_Builtins/2026-06-30-14-50-00.gh-issue-152708.aBcDeF.rst new file mode 100644 index 00000000000000..edcf99f56ff907 --- /dev/null +++ b/Misc/NEWS.d/next/Core_and_Builtins/2026-06-30-14-50-00.gh-issue-152708.aBcDeF.rst @@ -0,0 +1 @@ +Fix AST generation asymmetry where unary positive ``+`` was implicitly dropped in pattern match expressions, restoring parsing parity with unary negative ``-``. diff --git a/Parser/parser.c b/Parser/parser.c index 7d78449a6ba2f3..3f7385381276ed 100644 --- a/Parser/parser.c +++ b/Parser/parser.c @@ -9144,7 +9144,16 @@ signed_number_rule(Parser *p) ) { D(fprintf(stderr, "%*c+ signed_number[%d-%d]: %s succeeded!\n", p->level, ' ', _mark, p->mark, "'+' NUMBER")); - _res = number; + Token *_token = _PyPegen_get_last_nonnwhitespace_token(p); + if (_token == NULL) { + p->level--; + return NULL; + } + int _end_lineno = _token->end_lineno; + UNUSED(_end_lineno); // Only used by EXTRA macro + int _end_col_offset = _token->end_col_offset; + UNUSED(_end_col_offset); // Only used by EXTRA macro + _res = _PyAST_UnaryOp ( UAdd , number , EXTRA ); if ((_res == NULL || p->error_indicator) && PyErr_Occurred()) { p->error_indicator = 1; p->level--; @@ -9254,7 +9263,16 @@ signed_real_number_rule(Parser *p) ) { D(fprintf(stderr, "%*c+ signed_real_number[%d-%d]: %s succeeded!\n", p->level, ' ', _mark, p->mark, "'+' real_number")); - _res = real; + Token *_token = _PyPegen_get_last_nonnwhitespace_token(p); + if (_token == NULL) { + p->level--; + return NULL; + } + int _end_lineno = _token->end_lineno; + UNUSED(_end_lineno); // Only used by EXTRA macro + int _end_col_offset = _token->end_col_offset; + UNUSED(_end_col_offset); // Only used by EXTRA macro + _res = _PyAST_UnaryOp ( UAdd , real , EXTRA ); if ((_res == NULL || p->error_indicator) && PyErr_Occurred()) { p->error_indicator = 1; p->level--; diff --git a/Python/ast.c b/Python/ast.c index f625c59fe5bffc..1befd177811492 100644 --- a/Python/ast.c +++ b/Python/ast.c @@ -426,11 +426,11 @@ ensure_literal_number(expr_ty exp, bool allow_real, bool allow_imaginary) } static int -ensure_literal_negative(expr_ty exp, bool allow_real, bool allow_imaginary) +ensure_literal_signed(expr_ty exp, bool allow_real, bool allow_imaginary) { assert(exp->kind == UnaryOp_kind); - // Must be negation ... - if (exp->v.UnaryOp.op != USub) { + // Must be negation or positive ... + if (exp->v.UnaryOp.op != USub && exp->v.UnaryOp.op != UAdd) { return 0; } // ... of a constant ... @@ -461,7 +461,7 @@ ensure_literal_complex(expr_ty exp) } break; case UnaryOp_kind: - if (!ensure_literal_negative(left, /*real=*/true, /*imaginary=*/false)) { + if (!ensure_literal_signed(left, /*real=*/true, /*imaginary=*/false)) { return 0; } break; @@ -512,9 +512,9 @@ validate_pattern_match_value(expr_ty exp) // Constants and attribute lookups are always permitted return 1; case UnaryOp_kind: - // Negated numbers are permitted (whether real or imaginary) + // Signed numbers are permitted (whether real or imaginary) // Compiler will complain if AST folding doesn't create a constant - if (ensure_literal_negative(exp, /*real=*/true, /*imaginary=*/true)) { + if (ensure_literal_signed(exp, /*real=*/true, /*imaginary=*/true)) { return 1; } break; diff --git a/Python/ast_preprocess.c b/Python/ast_preprocess.c index 54dec3dfe04268..951b3f71522b25 100644 --- a/Python/ast_preprocess.c +++ b/Python/ast_preprocess.c @@ -867,11 +867,11 @@ fold_const_match_patterns(expr_ty node, PyArena *ctx_, _PyASTPreprocessState *st { case UnaryOp_kind: { - if (node->v.UnaryOp.op == USub && + if ((node->v.UnaryOp.op == USub || node->v.UnaryOp.op == UAdd) && node->v.UnaryOp.operand->kind == Constant_kind) { PyObject *operand = node->v.UnaryOp.operand->v.Constant.value; - PyObject *folded = PyNumber_Negative(operand); + PyObject *folded = node->v.UnaryOp.op == USub ? PyNumber_Negative(operand) : PyNumber_Positive(operand); return make_const(node, folded, ctx_); } break; _______________________________________________ Python-checkins mailing list -- [email protected] To unsubscribe send an email to [email protected] https://mail.python.org/mailman3//lists/python-checkins.python.org Member address: [email protected]
