Remove taint support

ext/psych/psych_parser.c

@@ -256,7 +256,6 @@ static VALUE parse(int argc, VALUE *argv, VALUE self)
     yaml_parser_t * parser;
     yaml_event_t event;
     int done = 0;
-    int tainted = 0;
     int state = 0;
     int parser_encoding = YAML_ANY_ENCODING;
     int encoding = rb_utf8_encindex();
@@ -275,13 +274,10 @@ static VALUE parse(int argc, VALUE *argv, VALUE self)
     yaml_parser_delete(parser);
     yaml_parser_initialize(parser);
 
-    if (OBJ_TAINTED(yaml)) tainted = 1;
-
     if (rb_respond_to(yaml, id_read)) {
 	yaml = transcode_io(yaml, &parser_encoding);
 	yaml_parser_set_encoding(parser, parser_encoding);
 	yaml_parser_set_input(parser, io_reader, (void *)yaml);
-	if (RTEST(rb_obj_is_kind_of(yaml, rb_cIO))) tainted = 1;
     } else {
 	StringValue(yaml);
 	yaml = transcode_string(yaml, &parser_encoding);
@@ -352,13 +348,11 @@ static VALUE parse(int argc, VALUE *argv, VALUE self)
 			VALUE prefix = Qnil;
 			if(start->handle) {
 			    handle = rb_str_new2((const char *)start->handle);
-			    if (tainted) OBJ_TAINT(handle);
 			    PSYCH_TRANSCODE(handle, encoding, internal_enc);
 			}
 
 			if(start->prefix) {
 			    prefix = rb_str_new2((const char *)start->prefix);
-			    if (tainted) OBJ_TAINT(prefix);
 			    PSYCH_TRANSCODE(prefix, encoding, internal_enc);
 			}
 
@@ -387,7 +381,6 @@ static VALUE parse(int argc, VALUE *argv, VALUE self)
 		VALUE alias = Qnil;
 		if(event.data.alias.anchor) {
 		    alias = rb_str_new2((const char *)event.data.alias.anchor);
-		    if (tainted) OBJ_TAINT(alias);
 		    PSYCH_TRANSCODE(alias, encoding, internal_enc);
 		}
 
@@ -406,19 +399,16 @@ static VALUE parse(int argc, VALUE *argv, VALUE self)
 		    (const char *)event.data.scalar.value,
 		    (long)event.data.scalar.length
 		    );
-		if (tainted) OBJ_TAINT(val);
 
 		PSYCH_TRANSCODE(val, encoding, internal_enc);
 
 		if(event.data.scalar.anchor) {
 		    anchor = rb_str_new2((const char *)event.data.scalar.anchor);
-		    if (tainted) OBJ_TAINT(anchor);
 		    PSYCH_TRANSCODE(anchor, encoding, internal_enc);
 		}
 
 		if(event.data.scalar.tag) {
 		    tag = rb_str_new2((const char *)event.data.scalar.tag);
-		    if (tainted) OBJ_TAINT(tag);
 		    PSYCH_TRANSCODE(tag, encoding, internal_enc);
 		}
 
@@ -448,14 +438,12 @@ static VALUE parse(int argc, VALUE *argv, VALUE self)
 		VALUE implicit, style;
 		if(event.data.sequence_start.anchor) {
 		    anchor = rb_str_new2((const char *)event.data.sequence_start.anchor);
-		    if (tainted) OBJ_TAINT(anchor);
 		    PSYCH_TRANSCODE(anchor, encoding, internal_enc);
 		}
 
 		tag = Qnil;
 		if(event.data.sequence_start.tag) {
 		    tag = rb_str_new2((const char *)event.data.sequence_start.tag);
-		    if (tainted) OBJ_TAINT(tag);
 		    PSYCH_TRANSCODE(tag, encoding, internal_enc);
 		}
 
@@ -484,13 +472,11 @@ static VALUE parse(int argc, VALUE *argv, VALUE self)
 		VALUE implicit, style;
 		if(event.data.mapping_start.anchor) {
 		    anchor = rb_str_new2((const char *)event.data.mapping_start.anchor);
-		    if (tainted) OBJ_TAINT(anchor);
 		    PSYCH_TRANSCODE(anchor, encoding, internal_enc);
 		}
 
 		if(event.data.mapping_start.tag) {
 		    tag = rb_str_new2((const char *)event.data.mapping_start.tag);
-		    if (tainted) OBJ_TAINT(tag);
 		    PSYCH_TRANSCODE(tag, encoding, internal_enc);
 		}
 

lib/psych/visitors/to_ruby.rb

@@ -368,11 +368,9 @@ def revive_hash hash, o
         hash
       end
 
-      if String.method_defined?(:-@)
+      if RUBY_VERSION < '2.7'
         def deduplicate key
           if key.is_a?(String)
-            # It is important to untaint the string, otherwise it won't
-            # be deduplicated into and fstring, but simply frozen.
             -(key.untaint)
           else
             key
@@ -381,9 +379,7 @@ def deduplicate key
       else
         def deduplicate key
           if key.is_a?(String)
-            # Deduplication is not supported by this implementation,
-            # but we emulate it's side effects
-            key.untaint.freeze
+            -key
           else
             key
           end