From 72e0aa2fd2b9c6da2caa5a9ef54f6495fc2890b0 Mon Sep 17 00:00:00 2001 From: Batuhan Taskaya Date: Thu, 21 May 2020 23:41:58 +0300 Subject: [PATCH] bpo-40176: Improve error messages for trailing comma on from import (GH-20294) --- Grammar/python.gram | 6 +- Lib/test/test_syntax.py | 8 + Parser/pegen/parse.c | 357 +++++++++++++++++++++++----------------- 3 files changed, 220 insertions(+), 151 deletions(-) diff --git a/Grammar/python.gram b/Grammar/python.gram index 40e7818d496..9bf2697a7e2 100644 --- a/Grammar/python.gram +++ b/Grammar/python.gram @@ -134,8 +134,9 @@ import_from[stmt_ty]: _Py_ImportFrom(NULL, b, _PyPegen_seq_count_dots(a), EXTRA) } import_from_targets[asdl_seq*]: | '(' a=import_from_as_names [','] ')' { a } - | import_from_as_names + | import_from_as_names !',' | '*' { _PyPegen_singleton_seq(p, CHECK(_PyPegen_alias_for_star(p))) } + | invalid_import_from_targets import_from_as_names[asdl_seq*]: | a=','.import_from_as_name+ { a } import_from_as_name[alias_ty]: @@ -670,3 +671,6 @@ invalid_double_type_comments: invalid_del_target: | a=star_expression &del_target_end { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "cannot delete %s", _PyPegen_get_expr_name(a)) } +invalid_import_from_targets: + | import_from_as_names ',' { + RAISE_SYNTAX_ERROR("trailing comma not allowed without surrounding parentheses") } diff --git a/Lib/test/test_syntax.py b/Lib/test/test_syntax.py index a82b444b67a..6d9c4e4b55e 100644 --- a/Lib/test/test_syntax.py +++ b/Lib/test/test_syntax.py @@ -641,6 +641,14 @@ SyntaxError: cannot assign to f-string expression Traceback (most recent call last): SyntaxError: cannot assign to f-string expression +>>> from t import x, +Traceback (most recent call last): +SyntaxError: trailing comma not allowed without surrounding parentheses + +>>> from t import x,y, +Traceback (most recent call last): +SyntaxError: trailing comma not allowed without surrounding parentheses + Corner-cases that used to fail to raise the correct error: >>> def f(*, x=lambda __debug__:0): pass diff --git a/Parser/pegen/parse.c b/Parser/pegen/parse.c index 286f72111e3..75aefa4d893 100644 --- a/Parser/pegen/parse.c +++ b/Parser/pegen/parse.c @@ -221,154 +221,155 @@ static KeywordToken *reserved_keywords[] = { #define invalid_lambda_star_etc_type 1150 #define invalid_double_type_comments_type 1151 #define invalid_del_target_type 1152 -#define _loop0_1_type 1153 -#define _loop0_2_type 1154 -#define _loop0_4_type 1155 -#define _gather_3_type 1156 -#define _loop0_6_type 1157 -#define _gather_5_type 1158 -#define _loop0_8_type 1159 -#define _gather_7_type 1160 -#define _loop0_10_type 1161 -#define _gather_9_type 1162 -#define _loop1_11_type 1163 -#define _loop0_13_type 1164 -#define _gather_12_type 1165 -#define _tmp_14_type 1166 -#define _tmp_15_type 1167 -#define _tmp_16_type 1168 -#define _tmp_17_type 1169 -#define _tmp_18_type 1170 -#define _tmp_19_type 1171 -#define _tmp_20_type 1172 -#define _tmp_21_type 1173 -#define _loop1_22_type 1174 -#define _tmp_23_type 1175 -#define _tmp_24_type 1176 -#define _loop0_26_type 1177 -#define _gather_25_type 1178 -#define _loop0_28_type 1179 -#define _gather_27_type 1180 -#define _tmp_29_type 1181 -#define _loop0_30_type 1182 -#define _loop1_31_type 1183 -#define _loop0_33_type 1184 -#define _gather_32_type 1185 -#define _tmp_34_type 1186 -#define _loop0_36_type 1187 -#define _gather_35_type 1188 -#define _tmp_37_type 1189 -#define _loop0_39_type 1190 -#define _gather_38_type 1191 -#define _loop0_41_type 1192 -#define _gather_40_type 1193 -#define _loop0_43_type 1194 -#define _gather_42_type 1195 -#define _loop0_45_type 1196 -#define _gather_44_type 1197 -#define _tmp_46_type 1198 -#define _loop1_47_type 1199 -#define _tmp_48_type 1200 -#define _tmp_49_type 1201 -#define _tmp_50_type 1202 -#define _tmp_51_type 1203 -#define _tmp_52_type 1204 -#define _loop0_53_type 1205 -#define _loop0_54_type 1206 -#define _loop0_55_type 1207 -#define _loop1_56_type 1208 -#define _loop0_57_type 1209 -#define _loop1_58_type 1210 -#define _loop1_59_type 1211 -#define _loop1_60_type 1212 -#define _loop0_61_type 1213 -#define _loop1_62_type 1214 -#define _loop0_63_type 1215 -#define _loop1_64_type 1216 -#define _loop0_65_type 1217 -#define _loop1_66_type 1218 -#define _loop1_67_type 1219 -#define _tmp_68_type 1220 -#define _loop0_70_type 1221 -#define _gather_69_type 1222 -#define _loop1_71_type 1223 -#define _loop0_73_type 1224 -#define _gather_72_type 1225 -#define _loop1_74_type 1226 -#define _loop0_75_type 1227 -#define _loop0_76_type 1228 -#define _loop0_77_type 1229 -#define _loop1_78_type 1230 -#define _loop0_79_type 1231 -#define _loop1_80_type 1232 -#define _loop1_81_type 1233 -#define _loop1_82_type 1234 -#define _loop0_83_type 1235 -#define _loop1_84_type 1236 -#define _loop0_85_type 1237 -#define _loop1_86_type 1238 -#define _loop0_87_type 1239 -#define _loop1_88_type 1240 -#define _loop1_89_type 1241 -#define _loop1_90_type 1242 -#define _loop1_91_type 1243 -#define _tmp_92_type 1244 -#define _loop0_94_type 1245 -#define _gather_93_type 1246 -#define _tmp_95_type 1247 -#define _tmp_96_type 1248 -#define _tmp_97_type 1249 -#define _tmp_98_type 1250 -#define _loop1_99_type 1251 -#define _tmp_100_type 1252 -#define _tmp_101_type 1253 -#define _loop0_103_type 1254 -#define _gather_102_type 1255 -#define _loop1_104_type 1256 -#define _loop0_105_type 1257 -#define _loop0_106_type 1258 -#define _tmp_107_type 1259 -#define _tmp_108_type 1260 -#define _loop0_110_type 1261 -#define _gather_109_type 1262 -#define _loop0_112_type 1263 -#define _gather_111_type 1264 -#define _loop0_114_type 1265 -#define _gather_113_type 1266 -#define _loop0_116_type 1267 -#define _gather_115_type 1268 -#define _loop0_117_type 1269 -#define _loop0_119_type 1270 -#define _gather_118_type 1271 -#define _tmp_120_type 1272 -#define _loop0_122_type 1273 -#define _gather_121_type 1274 -#define _loop0_124_type 1275 -#define _gather_123_type 1276 -#define _tmp_125_type 1277 -#define _loop0_126_type 1278 -#define _tmp_127_type 1279 -#define _tmp_128_type 1280 -#define _tmp_129_type 1281 -#define _tmp_130_type 1282 -#define _loop0_131_type 1283 -#define _tmp_132_type 1284 -#define _tmp_133_type 1285 -#define _tmp_134_type 1286 -#define _tmp_135_type 1287 -#define _tmp_136_type 1288 -#define _tmp_137_type 1289 -#define _tmp_138_type 1290 -#define _tmp_139_type 1291 -#define _tmp_140_type 1292 -#define _tmp_141_type 1293 -#define _tmp_142_type 1294 -#define _tmp_143_type 1295 -#define _tmp_144_type 1296 -#define _tmp_145_type 1297 -#define _loop1_146_type 1298 -#define _tmp_147_type 1299 -#define _tmp_148_type 1300 +#define invalid_import_from_targets_type 1153 +#define _loop0_1_type 1154 +#define _loop0_2_type 1155 +#define _loop0_4_type 1156 +#define _gather_3_type 1157 +#define _loop0_6_type 1158 +#define _gather_5_type 1159 +#define _loop0_8_type 1160 +#define _gather_7_type 1161 +#define _loop0_10_type 1162 +#define _gather_9_type 1163 +#define _loop1_11_type 1164 +#define _loop0_13_type 1165 +#define _gather_12_type 1166 +#define _tmp_14_type 1167 +#define _tmp_15_type 1168 +#define _tmp_16_type 1169 +#define _tmp_17_type 1170 +#define _tmp_18_type 1171 +#define _tmp_19_type 1172 +#define _tmp_20_type 1173 +#define _tmp_21_type 1174 +#define _loop1_22_type 1175 +#define _tmp_23_type 1176 +#define _tmp_24_type 1177 +#define _loop0_26_type 1178 +#define _gather_25_type 1179 +#define _loop0_28_type 1180 +#define _gather_27_type 1181 +#define _tmp_29_type 1182 +#define _loop0_30_type 1183 +#define _loop1_31_type 1184 +#define _loop0_33_type 1185 +#define _gather_32_type 1186 +#define _tmp_34_type 1187 +#define _loop0_36_type 1188 +#define _gather_35_type 1189 +#define _tmp_37_type 1190 +#define _loop0_39_type 1191 +#define _gather_38_type 1192 +#define _loop0_41_type 1193 +#define _gather_40_type 1194 +#define _loop0_43_type 1195 +#define _gather_42_type 1196 +#define _loop0_45_type 1197 +#define _gather_44_type 1198 +#define _tmp_46_type 1199 +#define _loop1_47_type 1200 +#define _tmp_48_type 1201 +#define _tmp_49_type 1202 +#define _tmp_50_type 1203 +#define _tmp_51_type 1204 +#define _tmp_52_type 1205 +#define _loop0_53_type 1206 +#define _loop0_54_type 1207 +#define _loop0_55_type 1208 +#define _loop1_56_type 1209 +#define _loop0_57_type 1210 +#define _loop1_58_type 1211 +#define _loop1_59_type 1212 +#define _loop1_60_type 1213 +#define _loop0_61_type 1214 +#define _loop1_62_type 1215 +#define _loop0_63_type 1216 +#define _loop1_64_type 1217 +#define _loop0_65_type 1218 +#define _loop1_66_type 1219 +#define _loop1_67_type 1220 +#define _tmp_68_type 1221 +#define _loop0_70_type 1222 +#define _gather_69_type 1223 +#define _loop1_71_type 1224 +#define _loop0_73_type 1225 +#define _gather_72_type 1226 +#define _loop1_74_type 1227 +#define _loop0_75_type 1228 +#define _loop0_76_type 1229 +#define _loop0_77_type 1230 +#define _loop1_78_type 1231 +#define _loop0_79_type 1232 +#define _loop1_80_type 1233 +#define _loop1_81_type 1234 +#define _loop1_82_type 1235 +#define _loop0_83_type 1236 +#define _loop1_84_type 1237 +#define _loop0_85_type 1238 +#define _loop1_86_type 1239 +#define _loop0_87_type 1240 +#define _loop1_88_type 1241 +#define _loop1_89_type 1242 +#define _loop1_90_type 1243 +#define _loop1_91_type 1244 +#define _tmp_92_type 1245 +#define _loop0_94_type 1246 +#define _gather_93_type 1247 +#define _tmp_95_type 1248 +#define _tmp_96_type 1249 +#define _tmp_97_type 1250 +#define _tmp_98_type 1251 +#define _loop1_99_type 1252 +#define _tmp_100_type 1253 +#define _tmp_101_type 1254 +#define _loop0_103_type 1255 +#define _gather_102_type 1256 +#define _loop1_104_type 1257 +#define _loop0_105_type 1258 +#define _loop0_106_type 1259 +#define _tmp_107_type 1260 +#define _tmp_108_type 1261 +#define _loop0_110_type 1262 +#define _gather_109_type 1263 +#define _loop0_112_type 1264 +#define _gather_111_type 1265 +#define _loop0_114_type 1266 +#define _gather_113_type 1267 +#define _loop0_116_type 1268 +#define _gather_115_type 1269 +#define _loop0_117_type 1270 +#define _loop0_119_type 1271 +#define _gather_118_type 1272 +#define _tmp_120_type 1273 +#define _loop0_122_type 1274 +#define _gather_121_type 1275 +#define _loop0_124_type 1276 +#define _gather_123_type 1277 +#define _tmp_125_type 1278 +#define _loop0_126_type 1279 +#define _tmp_127_type 1280 +#define _tmp_128_type 1281 +#define _tmp_129_type 1282 +#define _tmp_130_type 1283 +#define _loop0_131_type 1284 +#define _tmp_132_type 1285 +#define _tmp_133_type 1286 +#define _tmp_134_type 1287 +#define _tmp_135_type 1288 +#define _tmp_136_type 1289 +#define _tmp_137_type 1290 +#define _tmp_138_type 1291 +#define _tmp_139_type 1292 +#define _tmp_140_type 1293 +#define _tmp_141_type 1294 +#define _tmp_142_type 1295 +#define _tmp_143_type 1296 +#define _tmp_144_type 1297 +#define _tmp_145_type 1298 +#define _loop1_146_type 1299 +#define _tmp_147_type 1300 +#define _tmp_148_type 1301 static mod_ty file_rule(Parser *p); static mod_ty interactive_rule(Parser *p); @@ -523,6 +524,7 @@ static void *invalid_star_etc_rule(Parser *p); static void *invalid_lambda_star_etc_rule(Parser *p); static void *invalid_double_type_comments_rule(Parser *p); static void *invalid_del_target_rule(Parser *p); +static void *invalid_import_from_targets_rule(Parser *p); static asdl_seq *_loop0_1_rule(Parser *p); static asdl_seq *_loop0_2_rule(Parser *p); static asdl_seq *_loop0_4_rule(Parser *p); @@ -2592,7 +2594,11 @@ import_from_rule(Parser *p) return _res; } -// import_from_targets: '(' import_from_as_names ','? ')' | import_from_as_names | '*' +// import_from_targets: +// | '(' import_from_as_names ','? ')' +// | import_from_as_names !',' +// | '*' +// | invalid_import_from_targets static asdl_seq* import_from_targets_rule(Parser *p) { @@ -2629,13 +2635,15 @@ import_from_targets_rule(Parser *p) } p->mark = _mark; } - { // import_from_as_names + { // import_from_as_names !',' if (p->error_indicator) { return NULL; } asdl_seq* import_from_as_names_var; if ( (import_from_as_names_var = import_from_as_names_rule(p)) // import_from_as_names + && + _PyPegen_lookahead_with_int(0, _PyPegen_expect_token, p, 12) // token=',' ) { _res = import_from_as_names_var; @@ -2661,6 +2669,20 @@ import_from_targets_rule(Parser *p) } p->mark = _mark; } + { // invalid_import_from_targets + if (p->error_indicator) { + return NULL; + } + void *invalid_import_from_targets_var; + if ( + (invalid_import_from_targets_var = invalid_import_from_targets_rule(p)) // invalid_import_from_targets + ) + { + _res = invalid_import_from_targets_var; + goto done; + } + p->mark = _mark; + } _res = NULL; done: return _res; @@ -12213,6 +12235,41 @@ invalid_del_target_rule(Parser *p) return _res; } +// invalid_import_from_targets: import_from_as_names ',' +static void * +invalid_import_from_targets_rule(Parser *p) +{ + if (p->error_indicator) { + return NULL; + } + void * _res = NULL; + int _mark = p->mark; + { // import_from_as_names ',' + if (p->error_indicator) { + return NULL; + } + Token * _literal; + asdl_seq* import_from_as_names_var; + if ( + (import_from_as_names_var = import_from_as_names_rule(p)) // import_from_as_names + && + (_literal = _PyPegen_expect_token(p, 12)) // token=',' + ) + { + _res = RAISE_SYNTAX_ERROR ( "trailing comma not allowed without surrounding parentheses" ); + if (_res == NULL && PyErr_Occurred()) { + p->error_indicator = 1; + return NULL; + } + goto done; + } + p->mark = _mark; + } + _res = NULL; + done: + return _res; +} + // _loop0_1: NEWLINE static asdl_seq * _loop0_1_rule(Parser *p)