Ensure the tstring and encodings are never null for Strings and Symbols

Author: eregon

src/main/java/org/truffleruby/core/string/RubyString.java

@@ -34,6 +34,8 @@
 import com.oracle.truffle.api.object.Shape;
 import org.truffleruby.language.library.RubyStringLibrary;
 
+import java.util.Objects;
+
 @ExportLibrary(RubyLibrary.class)
 @ExportLibrary(InteropLibrary.class)
 @ImportStatic(RubyBaseNode.class)
@@ -53,19 +55,19 @@ public RubyString(
         super(rubyClass, shape);
         assert tstring.isCompatibleToUncached(rubyEncoding.tencoding);
         this.frozen = frozen;
-        this.tstring = tstring;
-        this.encoding = rubyEncoding;
+        this.tstring = Objects.requireNonNull(tstring);
+        this.encoding = Objects.requireNonNull(rubyEncoding);
     }
 
     public void setTString(AbstractTruffleString tstring) {
         assert tstring.isCompatibleToUncached(getEncodingUncached().tencoding);
-        this.tstring = tstring;
+        this.tstring = Objects.requireNonNull(tstring);
     }
 
     public void setTString(AbstractTruffleString tstring, RubyEncoding encoding) {
         assert tstring.isCompatibleToUncached(encoding.tencoding);
-        this.tstring = tstring;
-        this.encoding = encoding;
+        this.tstring = Objects.requireNonNull(tstring);
+        this.encoding = Objects.requireNonNull(encoding);
     }
 
     public void clearCodeRange() {

src/main/java/org/truffleruby/core/symbol/RubySymbol.java

@@ -31,6 +31,8 @@
 import org.truffleruby.parser.IdentifierType;
 import org.truffleruby.parser.Identifiers;
 
+import java.util.Objects;
+
 @ExportLibrary(InteropLibrary.class)
 public final class RubySymbol extends ImmutableRubyObjectNotCopyable implements TruffleObject {
 
@@ -51,9 +53,9 @@ public final class RubySymbol extends ImmutableRubyObjectNotCopyable implements
     RubySymbol(String string, TruffleString tstring, RubyEncoding encoding, long id) {
         assert tstring.isManaged();
         assert tstring.isCompatibleToUncached(encoding.tencoding);
-        this.encoding = encoding;
-        this.string = string;
-        this.tstring = tstring;
+        this.encoding = Objects.requireNonNull(encoding);
+        this.string = Objects.requireNonNull(string);
+        this.tstring = Objects.requireNonNull(tstring);
         this.javaStringHashCode = string.hashCode();
         this.id = id;
         this.type = Identifiers.stringToType(string);