Use "%empty" in the parsers, instead of comments

The annotation %empty is properly enforced: warnings when it's
missing, and errors when it's inappropriate.  Support for %empty was
introduced in Bison 3.0.

Pass -Wempty-rule to Bison.

Closes GH-5134

diff --git a/Zend/Makefile.frag b/Zend/Makefile.frag
index c5728af3c1113fb0aeae840fc40dee2a240b1aee..2f3c2d948d67d55b3bb85231d36523b59d7c9fda 100644 (file)
--- a/Zend/Makefile.frag
+++ b/Zend/Makefile.frag
@@ -13,7 +13,7 @@ $(srcdir)/zend_language_parser.c: $(srcdir)/zend_language_parser.y
 # Tweak zendparse to be exported through ZEND_API. This has to be revisited once
 # bison supports foreign skeletons and that bison version is used. Read
 # https://git.savannah.gnu.org/cgit/bison.git/tree/data/README.md for more.
-       @$(YACC) -p zend -v -d $(srcdir)/zend_language_parser.y -o $@
+       @$(YACC) $(YFLAGS) -p zend -v -d $(srcdir)/zend_language_parser.y -o $@
        @$(SED) -e 's,^int zendparse\(.*\),ZEND_API int zendparse\1,g' < $@ \
        > $@.tmp && \
        mv $@.tmp $@
@@ -27,7 +27,7 @@ $(srcdir)/zend_language_parser.c: $(srcdir)/zend_language_parser.y
 
 $(srcdir)/zend_ini_parser.h: $(srcdir)/zend_ini_parser.c
 $(srcdir)/zend_ini_parser.c: $(srcdir)/zend_ini_parser.y
-       @$(YACC) -p ini_ -v -d $(srcdir)/zend_ini_parser.y -o $@
+       @$(YACC) $(YFLAGS) -p ini_ -v -d $(srcdir)/zend_ini_parser.y -o $@
 
 $(srcdir)/zend_ini_scanner.c: $(srcdir)/zend_ini_scanner.l
        @(cd $(top_srcdir); $(RE2C) $(RE2C_FLAGS) --no-generation-date --case-inverted -cbdFt Zend/zend_ini_scanner_defs.h -oZend/zend_ini_scanner.c Zend/zend_ini_scanner.l)

diff --git a/Zend/zend_ini_parser.y b/Zend/zend_ini_parser.y
index 749f929a9bf1bdb3db71e0546658b921f6800ef8..9e350664ba1fbbeb9fdc8b655824693e1bbf7989 100644 (file)
--- a/Zend/zend_ini_parser.y
+++ b/Zend/zend_ini_parser.y
@@ -317,7 +317,7 @@ static void zval_ini_dtor(zval *zv)
 
 statement_list:
                statement_list statement
-       |       /* empty */
+       |       %empty
 ;
 
 statement:
@@ -351,7 +351,7 @@ statement:
 
 section_string_or_value:
                var_string_list_section                 { $$ = $1; }
-       |       /* empty */                                             { zend_ini_init_string(&$$); }
+       |       %empty                                          { zend_ini_init_string(&$$); }
 ;
 
 string_or_value:
@@ -364,13 +364,13 @@ string_or_value:
 
 option_offset:
                var_string_list                                 { $$ = $1; }
-       |       /* empty */                                             { zend_ini_init_string(&$$); }
+       |       %empty                                          { zend_ini_init_string(&$$); }
 ;
 
 encapsed_list:
                encapsed_list cfg_var_ref               { zend_ini_add_string(&$$, &$1, &$2); zend_string_free(Z_STR($2)); }
        |       encapsed_list TC_QUOTED_STRING  { zend_ini_add_string(&$$, &$1, &$2); zend_string_free(Z_STR($2)); }
-       |       /* empty */                                             { zend_ini_init_string(&$$); }
+       |       %empty                                          { zend_ini_init_string(&$$); }
 ;
 
 var_string_list_section:

diff --git a/Zend/zend_language_parser.y b/Zend/zend_language_parser.y
index 5f4d6a7540ad3f18a710c411a0062d8cc3599e0a..4fe6f77bb1662b91627f305e62d2ff0f8d5f6f7d 100644 (file)
--- a/Zend/zend_language_parser.y
+++ b/Zend/zend_language_parser.y
@@ -297,7 +297,7 @@ identifier:
 
 top_statement_list:
                top_statement_list top_statement { $$ = zend_ast_list_add($1, $2); }
-       |       /* empty */ { $$ = zend_ast_create_list(0, ZEND_AST_STMT_LIST); }
+       |       %empty { $$ = zend_ast_create_list(0, ZEND_AST_STMT_LIST); }
 ;
 
 namespace_name:
@@ -357,7 +357,7 @@ mixed_group_use_declaration:
 ;
 
 possible_comma:
-               /* empty */
+               %empty
        |       ','
 ;
 
@@ -407,7 +407,7 @@ const_list:
 inner_statement_list:
                inner_statement_list inner_statement
                        { $$ = zend_ast_list_add($1, $2); }
-       |       /* empty */
+       |       %empty
                        { $$ = zend_ast_create_list(0, ZEND_AST_STMT_LIST); }
 ;
 
@@ -463,7 +463,7 @@ statement:
 ;
 
 catch_list:
-               /* empty */
+               %empty
                        { $$ = zend_ast_create_list(0, ZEND_AST_CATCH_LIST); }
        |       catch_list T_CATCH '(' catch_name_list T_VARIABLE ')' '{' inner_statement_list '}'
                        { $$ = zend_ast_list_add($1, zend_ast_create(ZEND_AST_CATCH, $4, $5, $8)); }
@@ -475,7 +475,7 @@ catch_name_list:
 ;
 
 finally_statement:
-               /* empty */ { $$ = NULL; }
+               %empty { $$ = NULL; }
        |       T_FINALLY '{' inner_statement_list '}' { $$ = $3; }
 ;
 
@@ -496,12 +496,12 @@ function_declaration_statement:
 ;
 
 is_reference:
-               /* empty */     { $$ = 0; }
+               %empty  { $$ = 0; }
        |       '&'                     { $$ = ZEND_PARAM_REF; }
 ;
 
 is_variadic:
-               /* empty */ { $$ = 0; }
+               %empty { $$ = 0; }
        |       T_ELLIPSIS  { $$ = ZEND_PARAM_VARIADIC; }
 ;
 
@@ -538,17 +538,17 @@ interface_declaration_statement:
 ;
 
 extends_from:
-               /* empty */                             { $$ = NULL; }
+               %empty                          { $$ = NULL; }
        |       T_EXTENDS class_name    { $$ = $2; }
 ;
 
 interface_extends_list:
-               /* empty */                             { $$ = NULL; }
+               %empty                          { $$ = NULL; }
        |       T_EXTENDS class_name_list       { $$ = $2; }
 ;
 
 implements_list:
-               /* empty */                                     { $$ = NULL; }
+               %empty                                  { $$ = NULL; }
        |       T_IMPLEMENTS class_name_list    { $$ = $2; }
 ;
 
@@ -582,7 +582,7 @@ switch_case_list:
 ;
 
 case_list:
-               /* empty */ { $$ = zend_ast_create_list(0, ZEND_AST_SWITCH_LIST); }
+               %empty { $$ = zend_ast_create_list(0, ZEND_AST_SWITCH_LIST); }
        |       case_list T_CASE expr case_separator inner_statement_list
                        { $$ = zend_ast_list_add($1, zend_ast_create(ZEND_AST_SWITCH_CASE, $3, $5)); }
        |       case_list T_DEFAULT case_separator inner_statement_list
@@ -634,7 +634,7 @@ alt_if_stmt:
 
 parameter_list:
                non_empty_parameter_list { $$ = $1; }
-       |       /* empty */     { $$ = zend_ast_create_list(0, ZEND_AST_PARAM_LIST); }
+       |       %empty  { $$ = zend_ast_create_list(0, ZEND_AST_PARAM_LIST); }
 ;
 
 
@@ -654,7 +654,7 @@ parameter:
 
 
 optional_type:
-               /* empty */     { $$ = NULL; }
+               %empty  { $$ = NULL; }
        |       type_expr       { $$ = $1; }
 ;
 
@@ -676,7 +676,7 @@ union_type:
 ;
 
 return_type:
-               /* empty */     { $$ = NULL; }
+               %empty  { $$ = NULL; }
        |       ':' type_expr   { $$ = $2; }
 ;
 
@@ -722,7 +722,7 @@ static_var:
 class_statement_list:
                class_statement_list class_statement
                        { $$ = zend_ast_list_add($1, $2); }
-       |       /* empty */
+       |       %empty
                        { $$ = zend_ast_create_list(0, ZEND_AST_STMT_LIST); }
 ;
 
@@ -802,7 +802,7 @@ variable_modifiers:
 ;
 
 method_modifiers:
-               /* empty */                                             { $$ = ZEND_ACC_PUBLIC; }
+               %empty                                          { $$ = ZEND_ACC_PUBLIC; }
        |       non_empty_member_modifiers
                        { $$ = $1; if (!($$ & ZEND_ACC_PPP_MASK)) { $$ |= ZEND_ACC_PUBLIC; } }
 ;
@@ -856,7 +856,7 @@ echo_expr:
 ;
 
 for_exprs:
-               /* empty */                     { $$ = NULL; }
+               %empty                  { $$ = NULL; }
        |       non_empty_for_exprs     { $$ = $1; }
 ;
 
@@ -1026,24 +1026,24 @@ function:
 ;
 
 backup_doc_comment:
-       /* empty */ { $$ = CG(doc_comment); CG(doc_comment) = NULL; }
+       %empty { $$ = CG(doc_comment); CG(doc_comment) = NULL; }
 ;
 
 backup_fn_flags:
-       %prec PREC_ARROW_FUNCTION /* empty */ { $$ = CG(extra_fn_flags); CG(extra_fn_flags) = 0; }
+       %prec PREC_ARROW_FUNCTION %empty { $$ = CG(extra_fn_flags); CG(extra_fn_flags) = 0; }
 ;
 
 backup_lex_pos:
-       /* empty */ { $$ = LANG_SCNG(yy_text); }
+       %empty { $$ = LANG_SCNG(yy_text); }
 ;
 
 returns_ref:
-               /* empty */     { $$ = 0; }
+               %empty  { $$ = 0; }
        |       '&'                     { $$ = ZEND_ACC_RETURN_REFERENCE; }
 ;
 
 lexical_vars:
-               /* empty */ { $$ = NULL; }
+               %empty { $$ = NULL; }
        |       T_USE '(' lexical_var_list ')' { $$ = $3; }
 ;
 
@@ -1081,12 +1081,12 @@ class_name_reference:
 ;
 
 exit_expr:
-               /* empty */                             { $$ = NULL; }
+               %empty                          { $$ = NULL; }
        |       '(' optional_expr ')'   { $$ = $2; }
 ;
 
 backticks_expr:
-               /* empty */
+               %empty
                        { $$ = zend_ast_create_zval_from_str(ZSTR_EMPTY_ALLOC()); }
        |       T_ENCAPSED_AND_WHITESPACE { $$ = $1; }
        |       encaps_list { $$ = $1; }
@@ -1094,7 +1094,7 @@ backticks_expr:
 
 
 ctor_arguments:
-               /* empty */     { $$ = zend_ast_create_list(0, ZEND_AST_ARG_LIST); }
+               %empty  { $$ = zend_ast_create_list(0, ZEND_AST_ARG_LIST); }
        |       argument_list { $$ = $1; }
 ;
 
@@ -1134,7 +1134,7 @@ constant:
 ;
 
 optional_expr:
-               /* empty */     { $$ = NULL; }
+               %empty  { $$ = NULL; }
        |       expr            { $$ = $1; }
 ;
 
@@ -1223,7 +1223,7 @@ array_pair_list:
 ;
 
 possible_array_pair:
-               /* empty */ { $$ = NULL; }
+               %empty { $$ = NULL; }
        |       array_pair  { $$ = $1; }
 ;
 

diff --git a/build/php.m4 b/build/php.m4
index 8f7971fda8a56b952ae1a0154a33890127590f38..87527f43813cfaa44bbbd84bc00c6a1de35d328d 100644 (file)
--- a/build/php.m4
+++ b/build/php.m4
@@ -1815,6 +1815,7 @@ AC_DEFUN([PHP_PROG_BISON], [
     done
 
     if test "$php_bison_check" != "invalid"; then
+      AC_SUBST([YFLAGS], [-Wempty-rule])
       AC_MSG_RESULT([$php_bison_version (ok)])
     else
       AC_MSG_RESULT([$php_bison_version])

diff --git a/ext/json/Makefile.frag b/ext/json/Makefile.frag
index 8719b6607fdcd15f4c56f5a20778d85745f8e86c..f5fe3c3306598b24a54185a2204b7ba09f2302c9 100644 (file)
--- a/ext/json/Makefile.frag
+++ b/ext/json/Makefile.frag
@@ -2,4 +2,4 @@ $(srcdir)/json_scanner.c: $(srcdir)/json_scanner.re
        @$(RE2C) $(RE2C_FLAGS) -t $(srcdir)/php_json_scanner_defs.h --no-generation-date -bci -o $@ $(srcdir)/json_scanner.re
 
 $(srcdir)/json_parser.tab.c: $(srcdir)/json_parser.y
-       @$(YACC) --defines -l $(srcdir)/json_parser.y -o $@
+       @$(YACC) $(YFLAGS) --defines -l $(srcdir)/json_parser.y -o $@

diff --git a/ext/json/json_parser.y b/ext/json/json_parser.y
index ec5e4e81cfa7f9632fc2ed13252136d33f073742..833a772807c31118612f968f5570090af655b693 100644 (file)
--- a/ext/json/json_parser.y
+++ b/ext/json/json_parser.y
@@ -1,3 +1,4 @@
+%require "3.0"
 %code top {
 /*
   +----------------------------------------------------------------------+
@@ -118,7 +119,7 @@ object_end:
 ;
 
 members:
-               /* empty */
+               %empty
                        {
                                if ((parser->scanner.options & PHP_JSON_OBJECT_AS_ARRAY) && parser->methods.object_create == php_json_parser_object_create) {
                                        ZVAL_EMPTY_ARRAY(&$$);
@@ -182,7 +183,7 @@ array_end:
 ;
 
 elements:
-               /* empty */
+               %empty
                        {
                                if (parser->methods.array_create == php_json_parser_array_create) {
                                        ZVAL_EMPTY_ARRAY(&$$);

diff --git a/sapi/phpdbg/Makefile.frag b/sapi/phpdbg/Makefile.frag
index 65377e608a676ac305d2200ae8577203207b320c..448cc3676b6a1fb8578bff4596176c5a799e1e11 100644 (file)
--- a/sapi/phpdbg/Makefile.frag
+++ b/sapi/phpdbg/Makefile.frag
@@ -18,7 +18,7 @@ $(srcdir)/phpdbg_lexer.c: $(srcdir)/phpdbg_lexer.l
 
 $(srcdir)/phpdbg_parser.h: $(srcdir)/phpdbg_parser.c
 $(srcdir)/phpdbg_parser.c: $(srcdir)/phpdbg_parser.y
-       @$(YACC) -p phpdbg_ -v -d $(srcdir)/phpdbg_parser.y -o $@
+       @$(YACC) $(YFLAGS) -p phpdbg_ -v -d $(srcdir)/phpdbg_parser.y -o $@
 
 install-phpdbg: $(BUILD_BINARY)
        @echo "Installing phpdbg binary:         $(INSTALL_ROOT)$(bindir)/"

diff --git a/sapi/phpdbg/phpdbg_parser.y b/sapi/phpdbg/phpdbg_parser.y
index 3031ce5a807744f24367df6379b0b45cbf7b7c85..1384abe6fb78ec1b0e9d9aa8f53d2c0b898d876b 100644 (file)
--- a/sapi/phpdbg/phpdbg_parser.y
+++ b/sapi/phpdbg/phpdbg_parser.y
@@ -1,3 +1,4 @@
+%require "3.0"
 %{
 
 /*
@@ -65,7 +66,7 @@ typedef void* yyscan_t;
 input
        : command { $$ = $1; }
        | input T_SEPARATOR command { phpdbg_stack_separate($1.top); $$ = $3; }
-       | /* empty */
+       | %empty
        ;
 
 command
@@ -143,7 +144,7 @@ parameter
 
 req_id
        : T_REQ_ID { PHPDBG_G(req_id) = $1.num; }
-       | /* empty */
+       | %empty
 ;
 
 full_expression