diff --git a/Grammar/python.gram b/Grammar/python.gram index 9131835f7421bc..6b2a46aff0dcf0 100644 --- a/Grammar/python.gram +++ b/Grammar/python.gram @@ -923,7 +923,7 @@ fstring_conversion[ResultTokenWithMetadata*]: fstring_full_format_spec[ResultTokenWithMetadata*]: | colon=':' spec=fstring_format_spec* { _PyPegen_setup_full_format_spec(p, colon, (asdl_expr_seq *) spec, EXTRA) } fstring_format_spec[expr_ty]: - | t=FSTRING_MIDDLE { _PyPegen_constant_from_token(p, t) } + | t=FSTRING_MIDDLE { _PyPegen_decoded_constant_from_token(p, t) } | fstring_replacement_field fstring[expr_ty]: | a=FSTRING_START b=fstring_middle* c=FSTRING_END { _PyPegen_joined_str(p, a, (asdl_expr_seq*)b, c) } diff --git a/Lib/test/test_fstring.py b/Lib/test/test_fstring.py index 3ba2f943e6e968..031b94d8d58a39 100644 --- a/Lib/test/test_fstring.py +++ b/Lib/test/test_fstring.py @@ -764,6 +764,16 @@ def test_format_specifier_expressions(self): """f'{"s"!{"r"}}'""", ]) + def test_custom_format_specifier(self): + class CustomFormat: + def __format__(self, format_spec): + return format_spec + + self.assertEqual(f'{CustomFormat():\n}', '\n') + self.assertEqual(f'{CustomFormat():\u2603}', '☃') + with self.assertWarns(SyntaxWarning): + exec('f"{F():¯\_(ツ)_/¯}"', {'F': CustomFormat}) + def test_side_effect_order(self): class X: def __init__(self): diff --git a/Misc/NEWS.d/next/Core and Builtins/2023-06-02-11-37-12.gh-issue-105194.4eu56B.rst b/Misc/NEWS.d/next/Core and Builtins/2023-06-02-11-37-12.gh-issue-105194.4eu56B.rst new file mode 100644 index 00000000000000..adee74f5894b54 --- /dev/null +++ b/Misc/NEWS.d/next/Core and Builtins/2023-06-02-11-37-12.gh-issue-105194.4eu56B.rst @@ -0,0 +1,2 @@ +Do not escape with backslashes f-string format specifiers. Patch by Pablo +Galindo diff --git a/Parser/action_helpers.c b/Parser/action_helpers.c index 2411da2c705e78..7786124fde82d0 100644 --- a/Parser/action_helpers.c +++ b/Parser/action_helpers.c @@ -1350,6 +1350,25 @@ _PyPegen_joined_str(Parser *p, Token* a, asdl_expr_seq* raw_expressions, Token*b p->arena); } +expr_ty _PyPegen_decoded_constant_from_token(Parser* p, Token* tok) { + Py_ssize_t bsize; + char* bstr; + if (PyBytes_AsStringAndSize(tok->bytes, &bstr, &bsize) == -1) { + return NULL; + } + PyObject* str = _PyPegen_decode_string(p, 0, bstr, bsize, tok); + if (str == NULL) { + return NULL; + } + if (_PyArena_AddPyObject(p->arena, str) < 0) { + Py_DECREF(str); + return NULL; + } + return _PyAST_Constant(str, NULL, tok->lineno, tok->col_offset, + tok->end_lineno, tok->end_col_offset, + p->arena); +} + expr_ty _PyPegen_constant_from_token(Parser* p, Token* tok) { char* bstr = PyBytes_AsString(tok->bytes); if (bstr == NULL) { diff --git a/Parser/parser.c b/Parser/parser.c index 1705ebd456b5ff..006ee297974a61 100644 --- a/Parser/parser.c +++ b/Parser/parser.c @@ -16323,7 +16323,7 @@ fstring_format_spec_rule(Parser *p) ) { D(fprintf(stderr, "%*c+ fstring_format_spec[%d-%d]: %s succeeded!\n", p->level, ' ', _mark, p->mark, "FSTRING_MIDDLE")); - _res = _PyPegen_constant_from_token ( p , t ); + _res = _PyPegen_decoded_constant_from_token ( p , t ); if (_res == NULL && PyErr_Occurred()) { p->error_indicator = 1; p->level--; diff --git a/Parser/pegen.h b/Parser/pegen.h index 8800e9f97f5e04..fe13d10e6b83e3 100644 --- a/Parser/pegen.h +++ b/Parser/pegen.h @@ -328,6 +328,7 @@ expr_ty _PyPegen_collect_call_seqs(Parser *, asdl_expr_seq *, asdl_seq *, int lineno, int col_offset, int end_lineno, int end_col_offset, PyArena *arena); expr_ty _PyPegen_constant_from_token(Parser* p, Token* tok); +expr_ty _PyPegen_decoded_constant_from_token(Parser* p, Token* tok); expr_ty _PyPegen_constant_from_string(Parser* p, Token* tok); expr_ty _PyPegen_concatenate_strings(Parser *p, asdl_expr_seq *, int, int, int, int, PyArena *); expr_ty _PyPegen_FetchRawForm(Parser *p, int, int, int, int);