diff --git a/Grammar/python.gram b/Grammar/python.gram index b9ecd2273a5cae..e74a6ebdf6e37d 100644 --- a/Grammar/python.gram +++ b/Grammar/python.gram @@ -495,6 +495,7 @@ case_block[match_case_ty]: | invalid_case_block | "case" pattern=patterns guard=guard? ':' body=block { _PyAST_match_case(pattern, guard, body, p->arena) } + | invalid_case_pattern guard[expr_ty]: 'if' guard=named_expression { guard } @@ -1480,6 +1481,10 @@ invalid_case_block: | "case" patterns guard? NEWLINE { RAISE_SYNTAX_ERROR("expected ':'") } | a="case" patterns guard? ':' NEWLINE !INDENT { RAISE_INDENTATION_ERROR("expected an indented block after 'case' statement on line %d", a->lineno) } +invalid_case_pattern: + | "case" a=expression guard? ':' block { + RAISE_SYNTAX_ERROR_KNOWN_LOCATION( + a, "cannot use %s as case pattern", _PyPegen_get_expr_name(a)) } invalid_as_pattern: | or_pattern 'as' a="_" { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "cannot use '_' as a target") } | or_pattern 'as' a=expression { diff --git a/Lib/test/test_exceptions.py b/Lib/test/test_exceptions.py index 59f77f91d85e5c..e219e27de2b4c7 100644 --- a/Lib/test/test_exceptions.py +++ b/Lib/test/test_exceptions.py @@ -248,7 +248,7 @@ def testSyntaxErrorOffset(self): check('[\nfile\nfor str(file)\nin\n[]\n]', 3, 5) check('[file for\n str(file) in []]', 2, 2) check("ages = {'Alice'=22, 'Bob'=23}", 1, 9) - check('match ...:\n case {**rest, "key": value}:\n ...', 2, 19) + check('match ...:\n case {**rest, "key": value}:\n ...', 2, 10) check("[a b c d e f]", 1, 2) check("for x yfff:", 1, 7) check("f(a for a in b, c)", 1, 3, 1, 15) diff --git a/Lib/test/test_syntax.py b/Lib/test/test_syntax.py index e334f48179ec84..49eeb5d0739262 100644 --- a/Lib/test/test_syntax.py +++ b/Lib/test/test_syntax.py @@ -374,13 +374,38 @@ ... case {**rest, "key": value}: ... ... Traceback (most recent call last): -SyntaxError: invalid syntax +SyntaxError: cannot use dict literal as case pattern >>> match ...: ... case {**_}: ... ... Traceback (most recent call last): -SyntaxError: invalid syntax +SyntaxError: cannot use dict literal as case pattern + +>>> match ...: +... case ...: ... +Traceback (most recent call last): +SyntaxError: cannot use ellipsis as case pattern + +>>> match ...: +... case 1 // 2: ... +Traceback (most recent call last): +SyntaxError: cannot use expression as case pattern + +>>> match ...: +... case {1, 2, 3}: ... +Traceback (most recent call last): +SyntaxError: cannot use set display as case pattern + +>>> match ...: +... case a[0]: ... +Traceback (most recent call last): +SyntaxError: cannot use subscript as case pattern + +>>> match ...: +... case a[0].method(): ... +Traceback (most recent call last): +SyntaxError: cannot use function call as case pattern # But prefixes of soft keywords should # still raise specialized errors diff --git a/Misc/NEWS.d/next/Core_and_Builtins/2025-09-13-12-51-34.gh-issue-138864.Otm5li.rst b/Misc/NEWS.d/next/Core_and_Builtins/2025-09-13-12-51-34.gh-issue-138864.Otm5li.rst new file mode 100644 index 00000000000000..b363a83c4b5b28 --- /dev/null +++ b/Misc/NEWS.d/next/Core_and_Builtins/2025-09-13-12-51-34.gh-issue-138864.Otm5li.rst @@ -0,0 +1,2 @@ +Improve :exc:`SyntaxError` message for using ``case`` with regular +expressions. diff --git a/Parser/parser.c b/Parser/parser.c index 8242c4dfabba35..2eadc5767ca641 100644 --- a/Parser/parser.c +++ b/Parser/parser.c @@ -332,204 +332,205 @@ static char *soft_keywords[] = { #define invalid_except_star_stmt_indent_type 1245 #define invalid_match_stmt_type 1246 #define invalid_case_block_type 1247 -#define invalid_as_pattern_type 1248 -#define invalid_class_pattern_type 1249 -#define invalid_class_argument_pattern_type 1250 -#define invalid_if_stmt_type 1251 -#define invalid_elif_stmt_type 1252 -#define invalid_else_stmt_type 1253 -#define invalid_while_stmt_type 1254 -#define invalid_for_stmt_type 1255 -#define invalid_def_raw_type 1256 -#define invalid_class_def_raw_type 1257 -#define invalid_double_starred_kvpairs_type 1258 -#define invalid_kvpair_type 1259 -#define invalid_starred_expression_unpacking_type 1260 -#define invalid_starred_expression_type 1261 -#define invalid_fstring_replacement_field_type 1262 -#define invalid_fstring_conversion_character_type 1263 -#define invalid_tstring_replacement_field_type 1264 -#define invalid_tstring_conversion_character_type 1265 -#define invalid_string_tstring_concat_type 1266 -#define invalid_arithmetic_type 1267 -#define invalid_factor_type 1268 -#define invalid_type_params_type 1269 -#define _loop0_1_type 1270 -#define _loop1_2_type 1271 -#define _loop0_3_type 1272 -#define _gather_4_type 1273 -#define _tmp_5_type 1274 -#define _tmp_6_type 1275 -#define _tmp_7_type 1276 -#define _tmp_8_type 1277 -#define _tmp_9_type 1278 -#define _tmp_10_type 1279 -#define _tmp_11_type 1280 -#define _loop1_12_type 1281 -#define _loop0_13_type 1282 -#define _gather_14_type 1283 -#define _tmp_15_type 1284 -#define _tmp_16_type 1285 -#define _loop0_17_type 1286 -#define _loop1_18_type 1287 -#define _loop0_19_type 1288 -#define _gather_20_type 1289 -#define _tmp_21_type 1290 -#define _loop0_22_type 1291 -#define _gather_23_type 1292 -#define _loop1_24_type 1293 -#define _tmp_25_type 1294 -#define _tmp_26_type 1295 -#define _loop0_27_type 1296 -#define _loop0_28_type 1297 -#define _loop1_29_type 1298 -#define _loop1_30_type 1299 -#define _loop0_31_type 1300 -#define _loop1_32_type 1301 -#define _loop0_33_type 1302 -#define _gather_34_type 1303 -#define _tmp_35_type 1304 -#define _loop1_36_type 1305 -#define _loop1_37_type 1306 -#define _loop1_38_type 1307 -#define _loop0_39_type 1308 -#define _gather_40_type 1309 -#define _tmp_41_type 1310 -#define _tmp_42_type 1311 -#define _tmp_43_type 1312 -#define _loop0_44_type 1313 -#define _gather_45_type 1314 -#define _loop0_46_type 1315 -#define _gather_47_type 1316 -#define _tmp_48_type 1317 -#define _loop0_49_type 1318 -#define _gather_50_type 1319 -#define _loop0_51_type 1320 -#define _gather_52_type 1321 -#define _loop0_53_type 1322 -#define _gather_54_type 1323 -#define _loop1_55_type 1324 -#define _loop1_56_type 1325 -#define _loop0_57_type 1326 -#define _gather_58_type 1327 -#define _loop1_59_type 1328 -#define _loop1_60_type 1329 -#define _loop1_61_type 1330 -#define _tmp_62_type 1331 -#define _loop0_63_type 1332 -#define _gather_64_type 1333 -#define _tmp_65_type 1334 -#define _tmp_66_type 1335 -#define _tmp_67_type 1336 -#define _tmp_68_type 1337 -#define _tmp_69_type 1338 -#define _loop0_70_type 1339 -#define _loop0_71_type 1340 -#define _loop1_72_type 1341 -#define _loop1_73_type 1342 -#define _loop0_74_type 1343 -#define _loop1_75_type 1344 -#define _loop0_76_type 1345 -#define _loop0_77_type 1346 -#define _loop0_78_type 1347 -#define _loop0_79_type 1348 -#define _loop1_80_type 1349 -#define _loop1_81_type 1350 -#define _tmp_82_type 1351 -#define _loop0_83_type 1352 -#define _gather_84_type 1353 -#define _loop1_85_type 1354 -#define _loop0_86_type 1355 -#define _tmp_87_type 1356 -#define _loop0_88_type 1357 -#define _gather_89_type 1358 -#define _tmp_90_type 1359 -#define _loop0_91_type 1360 -#define _gather_92_type 1361 -#define _loop0_93_type 1362 -#define _gather_94_type 1363 -#define _loop0_95_type 1364 -#define _loop0_96_type 1365 -#define _gather_97_type 1366 -#define _loop1_98_type 1367 -#define _tmp_99_type 1368 -#define _loop0_100_type 1369 -#define _gather_101_type 1370 -#define _loop0_102_type 1371 -#define _gather_103_type 1372 -#define _tmp_104_type 1373 -#define _tmp_105_type 1374 -#define _loop0_106_type 1375 -#define _gather_107_type 1376 -#define _tmp_108_type 1377 -#define _tmp_109_type 1378 -#define _tmp_110_type 1379 -#define _tmp_111_type 1380 -#define _tmp_112_type 1381 -#define _loop1_113_type 1382 -#define _tmp_114_type 1383 -#define _tmp_115_type 1384 -#define _tmp_116_type 1385 -#define _tmp_117_type 1386 -#define _tmp_118_type 1387 -#define _loop0_119_type 1388 -#define _loop0_120_type 1389 -#define _tmp_121_type 1390 -#define _tmp_122_type 1391 -#define _tmp_123_type 1392 -#define _tmp_124_type 1393 -#define _tmp_125_type 1394 -#define _tmp_126_type 1395 -#define _tmp_127_type 1396 -#define _tmp_128_type 1397 -#define _tmp_129_type 1398 -#define _loop0_130_type 1399 -#define _gather_131_type 1400 -#define _tmp_132_type 1401 -#define _tmp_133_type 1402 -#define _tmp_134_type 1403 -#define _tmp_135_type 1404 -#define _loop0_136_type 1405 -#define _gather_137_type 1406 -#define _tmp_138_type 1407 -#define _loop0_139_type 1408 -#define _gather_140_type 1409 -#define _loop0_141_type 1410 -#define _gather_142_type 1411 -#define _tmp_143_type 1412 -#define _loop0_144_type 1413 -#define _tmp_145_type 1414 -#define _tmp_146_type 1415 -#define _tmp_147_type 1416 -#define _tmp_148_type 1417 -#define _tmp_149_type 1418 -#define _tmp_150_type 1419 -#define _tmp_151_type 1420 -#define _tmp_152_type 1421 -#define _tmp_153_type 1422 -#define _tmp_154_type 1423 -#define _tmp_155_type 1424 -#define _tmp_156_type 1425 -#define _tmp_157_type 1426 -#define _tmp_158_type 1427 -#define _tmp_159_type 1428 -#define _tmp_160_type 1429 -#define _tmp_161_type 1430 -#define _tmp_162_type 1431 -#define _tmp_163_type 1432 -#define _tmp_164_type 1433 -#define _tmp_165_type 1434 -#define _tmp_166_type 1435 -#define _tmp_167_type 1436 -#define _tmp_168_type 1437 -#define _tmp_169_type 1438 -#define _tmp_170_type 1439 -#define _loop0_171_type 1440 -#define _tmp_172_type 1441 -#define _tmp_173_type 1442 -#define _tmp_174_type 1443 -#define _tmp_175_type 1444 -#define _tmp_176_type 1445 +#define invalid_case_pattern_type 1248 +#define invalid_as_pattern_type 1249 +#define invalid_class_pattern_type 1250 +#define invalid_class_argument_pattern_type 1251 +#define invalid_if_stmt_type 1252 +#define invalid_elif_stmt_type 1253 +#define invalid_else_stmt_type 1254 +#define invalid_while_stmt_type 1255 +#define invalid_for_stmt_type 1256 +#define invalid_def_raw_type 1257 +#define invalid_class_def_raw_type 1258 +#define invalid_double_starred_kvpairs_type 1259 +#define invalid_kvpair_type 1260 +#define invalid_starred_expression_unpacking_type 1261 +#define invalid_starred_expression_type 1262 +#define invalid_fstring_replacement_field_type 1263 +#define invalid_fstring_conversion_character_type 1264 +#define invalid_tstring_replacement_field_type 1265 +#define invalid_tstring_conversion_character_type 1266 +#define invalid_string_tstring_concat_type 1267 +#define invalid_arithmetic_type 1268 +#define invalid_factor_type 1269 +#define invalid_type_params_type 1270 +#define _loop0_1_type 1271 +#define _loop1_2_type 1272 +#define _loop0_3_type 1273 +#define _gather_4_type 1274 +#define _tmp_5_type 1275 +#define _tmp_6_type 1276 +#define _tmp_7_type 1277 +#define _tmp_8_type 1278 +#define _tmp_9_type 1279 +#define _tmp_10_type 1280 +#define _tmp_11_type 1281 +#define _loop1_12_type 1282 +#define _loop0_13_type 1283 +#define _gather_14_type 1284 +#define _tmp_15_type 1285 +#define _tmp_16_type 1286 +#define _loop0_17_type 1287 +#define _loop1_18_type 1288 +#define _loop0_19_type 1289 +#define _gather_20_type 1290 +#define _tmp_21_type 1291 +#define _loop0_22_type 1292 +#define _gather_23_type 1293 +#define _loop1_24_type 1294 +#define _tmp_25_type 1295 +#define _tmp_26_type 1296 +#define _loop0_27_type 1297 +#define _loop0_28_type 1298 +#define _loop1_29_type 1299 +#define _loop1_30_type 1300 +#define _loop0_31_type 1301 +#define _loop1_32_type 1302 +#define _loop0_33_type 1303 +#define _gather_34_type 1304 +#define _tmp_35_type 1305 +#define _loop1_36_type 1306 +#define _loop1_37_type 1307 +#define _loop1_38_type 1308 +#define _loop0_39_type 1309 +#define _gather_40_type 1310 +#define _tmp_41_type 1311 +#define _tmp_42_type 1312 +#define _tmp_43_type 1313 +#define _loop0_44_type 1314 +#define _gather_45_type 1315 +#define _loop0_46_type 1316 +#define _gather_47_type 1317 +#define _tmp_48_type 1318 +#define _loop0_49_type 1319 +#define _gather_50_type 1320 +#define _loop0_51_type 1321 +#define _gather_52_type 1322 +#define _loop0_53_type 1323 +#define _gather_54_type 1324 +#define _loop1_55_type 1325 +#define _loop1_56_type 1326 +#define _loop0_57_type 1327 +#define _gather_58_type 1328 +#define _loop1_59_type 1329 +#define _loop1_60_type 1330 +#define _loop1_61_type 1331 +#define _tmp_62_type 1332 +#define _loop0_63_type 1333 +#define _gather_64_type 1334 +#define _tmp_65_type 1335 +#define _tmp_66_type 1336 +#define _tmp_67_type 1337 +#define _tmp_68_type 1338 +#define _tmp_69_type 1339 +#define _loop0_70_type 1340 +#define _loop0_71_type 1341 +#define _loop1_72_type 1342 +#define _loop1_73_type 1343 +#define _loop0_74_type 1344 +#define _loop1_75_type 1345 +#define _loop0_76_type 1346 +#define _loop0_77_type 1347 +#define _loop0_78_type 1348 +#define _loop0_79_type 1349 +#define _loop1_80_type 1350 +#define _loop1_81_type 1351 +#define _tmp_82_type 1352 +#define _loop0_83_type 1353 +#define _gather_84_type 1354 +#define _loop1_85_type 1355 +#define _loop0_86_type 1356 +#define _tmp_87_type 1357 +#define _loop0_88_type 1358 +#define _gather_89_type 1359 +#define _tmp_90_type 1360 +#define _loop0_91_type 1361 +#define _gather_92_type 1362 +#define _loop0_93_type 1363 +#define _gather_94_type 1364 +#define _loop0_95_type 1365 +#define _loop0_96_type 1366 +#define _gather_97_type 1367 +#define _loop1_98_type 1368 +#define _tmp_99_type 1369 +#define _loop0_100_type 1370 +#define _gather_101_type 1371 +#define _loop0_102_type 1372 +#define _gather_103_type 1373 +#define _tmp_104_type 1374 +#define _tmp_105_type 1375 +#define _loop0_106_type 1376 +#define _gather_107_type 1377 +#define _tmp_108_type 1378 +#define _tmp_109_type 1379 +#define _tmp_110_type 1380 +#define _tmp_111_type 1381 +#define _tmp_112_type 1382 +#define _loop1_113_type 1383 +#define _tmp_114_type 1384 +#define _tmp_115_type 1385 +#define _tmp_116_type 1386 +#define _tmp_117_type 1387 +#define _tmp_118_type 1388 +#define _loop0_119_type 1389 +#define _loop0_120_type 1390 +#define _tmp_121_type 1391 +#define _tmp_122_type 1392 +#define _tmp_123_type 1393 +#define _tmp_124_type 1394 +#define _tmp_125_type 1395 +#define _tmp_126_type 1396 +#define _tmp_127_type 1397 +#define _tmp_128_type 1398 +#define _tmp_129_type 1399 +#define _loop0_130_type 1400 +#define _gather_131_type 1401 +#define _tmp_132_type 1402 +#define _tmp_133_type 1403 +#define _tmp_134_type 1404 +#define _tmp_135_type 1405 +#define _loop0_136_type 1406 +#define _gather_137_type 1407 +#define _tmp_138_type 1408 +#define _loop0_139_type 1409 +#define _gather_140_type 1410 +#define _loop0_141_type 1411 +#define _gather_142_type 1412 +#define _tmp_143_type 1413 +#define _loop0_144_type 1414 +#define _tmp_145_type 1415 +#define _tmp_146_type 1416 +#define _tmp_147_type 1417 +#define _tmp_148_type 1418 +#define _tmp_149_type 1419 +#define _tmp_150_type 1420 +#define _tmp_151_type 1421 +#define _tmp_152_type 1422 +#define _tmp_153_type 1423 +#define _tmp_154_type 1424 +#define _tmp_155_type 1425 +#define _tmp_156_type 1426 +#define _tmp_157_type 1427 +#define _tmp_158_type 1428 +#define _tmp_159_type 1429 +#define _tmp_160_type 1430 +#define _tmp_161_type 1431 +#define _tmp_162_type 1432 +#define _tmp_163_type 1433 +#define _tmp_164_type 1434 +#define _tmp_165_type 1435 +#define _tmp_166_type 1436 +#define _tmp_167_type 1437 +#define _tmp_168_type 1438 +#define _tmp_169_type 1439 +#define _tmp_170_type 1440 +#define _loop0_171_type 1441 +#define _tmp_172_type 1442 +#define _tmp_173_type 1443 +#define _tmp_174_type 1444 +#define _tmp_175_type 1445 +#define _tmp_176_type 1446 static mod_ty file_rule(Parser *p); static mod_ty interactive_rule(Parser *p); @@ -779,6 +780,7 @@ static void *invalid_except_stmt_indent_rule(Parser *p); static void *invalid_except_star_stmt_indent_rule(Parser *p); static void *invalid_match_stmt_rule(Parser *p); static void *invalid_case_block_rule(Parser *p); +static void *invalid_case_pattern_rule(Parser *p); static void *invalid_as_pattern_rule(Parser *p); static void *invalid_class_pattern_rule(Parser *p); static asdl_pattern_seq* invalid_class_argument_pattern_rule(Parser *p); @@ -7906,7 +7908,10 @@ subject_expr_rule(Parser *p) return _res; } -// case_block: invalid_case_block | "case" patterns guard? ':' block +// case_block: +// | invalid_case_block +// | "case" patterns guard? ':' block +// | invalid_case_pattern static match_case_ty case_block_rule(Parser *p) { @@ -7974,6 +7979,25 @@ case_block_rule(Parser *p) D(fprintf(stderr, "%*c%s case_block[%d-%d]: %s failed!\n", p->level, ' ', p->error_indicator ? "ERROR!" : "-", _mark, p->mark, "\"case\" patterns guard? ':' block")); } + if (p->call_invalid_rules) { // invalid_case_pattern + if (p->error_indicator) { + p->level--; + return NULL; + } + D(fprintf(stderr, "%*c> case_block[%d-%d]: %s\n", p->level, ' ', _mark, p->mark, "invalid_case_pattern")); + void *invalid_case_pattern_var; + if ( + (invalid_case_pattern_var = invalid_case_pattern_rule(p)) // invalid_case_pattern + ) + { + D(fprintf(stderr, "%*c+ case_block[%d-%d]: %s succeeded!\n", p->level, ' ', _mark, p->mark, "invalid_case_pattern")); + _res = invalid_case_pattern_var; + goto done; + } + p->mark = _mark; + D(fprintf(stderr, "%*c%s case_block[%d-%d]: %s failed!\n", p->level, ' ', + p->error_indicator ? "ERROR!" : "-", _mark, p->mark, "invalid_case_pattern")); + } _res = NULL; done: p->level--; @@ -25307,6 +25331,62 @@ invalid_case_block_rule(Parser *p) return _res; } +// invalid_case_pattern: "case" expression guard? ':' block +static void * +invalid_case_pattern_rule(Parser *p) +{ + if (p->level++ == MAXSTACK || _Py_ReachedRecursionLimitWithMargin(PyThreadState_Get(), 1)) { + _Pypegen_stack_overflow(p); + } + if (p->error_indicator) { + p->level--; + return NULL; + } + void * _res = NULL; + int _mark = p->mark; + { // "case" expression guard? ':' block + if (p->error_indicator) { + p->level--; + return NULL; + } + D(fprintf(stderr, "%*c> invalid_case_pattern[%d-%d]: %s\n", p->level, ' ', _mark, p->mark, "\"case\" expression guard? ':' block")); + expr_ty _keyword; + Token * _literal; + void *_opt_var; + UNUSED(_opt_var); // Silence compiler warnings + expr_ty a; + asdl_stmt_seq* block_var; + if ( + (_keyword = _PyPegen_expect_soft_keyword(p, "case")) // soft_keyword='"case"' + && + (a = expression_rule(p)) // expression + && + (_opt_var = guard_rule(p), !p->error_indicator) // guard? + && + (_literal = _PyPegen_expect_token(p, 11)) // token=':' + && + (block_var = block_rule(p)) // block + ) + { + D(fprintf(stderr, "%*c+ invalid_case_pattern[%d-%d]: %s succeeded!\n", p->level, ' ', _mark, p->mark, "\"case\" expression guard? ':' block")); + _res = RAISE_SYNTAX_ERROR_KNOWN_LOCATION ( a , "cannot use %s as case pattern" , _PyPegen_get_expr_name ( a ) ); + if (_res == NULL && PyErr_Occurred()) { + p->error_indicator = 1; + p->level--; + return NULL; + } + goto done; + } + p->mark = _mark; + D(fprintf(stderr, "%*c%s invalid_case_pattern[%d-%d]: %s failed!\n", p->level, ' ', + p->error_indicator ? "ERROR!" : "-", _mark, p->mark, "\"case\" expression guard? ':' block")); + } + _res = NULL; + done: + p->level--; + return _res; +} + // invalid_as_pattern: or_pattern 'as' "_" | or_pattern 'as' expression static void * invalid_as_pattern_rule(Parser *p)