Generic object's format should reject any non-empty format spec

Author: steve-s

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/objects/object/ObjectBuiltins.java

@@ -90,6 +90,7 @@
 import com.oracle.graal.python.nodes.function.builtins.PythonVarargsBuiltinNode;
 import com.oracle.graal.python.nodes.object.GetClassNode;
 import com.oracle.graal.python.nodes.object.IsBuiltinClassProfile;
+import com.oracle.graal.python.nodes.truffle.PythonArithmeticTypes;
 import com.oracle.graal.python.nodes.util.SplitArgsNode;
 import com.oracle.truffle.api.CompilerDirectives;
 import com.oracle.truffle.api.CompilerDirectives.CompilationFinal;
@@ -100,6 +101,7 @@
 import com.oracle.truffle.api.dsl.ImportStatic;
 import com.oracle.truffle.api.dsl.NodeFactory;
 import com.oracle.truffle.api.dsl.Specialization;
+import com.oracle.truffle.api.dsl.TypeSystemReference;
 import com.oracle.truffle.api.frame.VirtualFrame;
 import com.oracle.truffle.api.interop.InteropLibrary;
 import com.oracle.truffle.api.interop.UnsupportedMessageException;
@@ -572,11 +574,16 @@ Object raise(Object self, @SuppressWarnings("unused") Object dict) {
     }
 
     @Builtin(name = __FORMAT__, minNumOfPositionalArgs = 2)
+    @TypeSystemReference(PythonArithmeticTypes.class)
     @GenerateNodeFactory
     abstract static class FormatNode extends PythonBinaryBuiltinNode {
+
         @Specialization(guards = "isString(formatString)")
-        Object format(VirtualFrame frame, Object self, @SuppressWarnings("unused") Object formatString,
+        Object format(VirtualFrame frame, Object self, String formatString,
                         @Cached("create(__STR__)") LookupAndCallUnaryNode strCall) {
+            if (formatString.length() > 0) {
+                raise(PythonBuiltinClassType.TypeError, ErrorMessages.UNSUPPORTED_FORMAT_STRING_PASSED_TO_P_FORMAT, self);
+            }
             return strCall.executeObject(frame, self);
         }
 

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/nodes/ErrorMessages.java

@@ -551,4 +551,5 @@ public abstract class ErrorMessages {
     public static final String HPY_LOAD_ERROR = "Could not load HPy C API from %s.";
     public static final String CANNOT_CONVERT_NEGATIVE_VALUE_TO_UNSIGNED_INT = "can't convert negative value to unsigned int";
     public static final String SEND_NON_NONE_TO_UNSTARTED_GENERATOR = "can't send non-None value to a just-started generator";
+    public static final String UNSUPPORTED_FORMAT_STRING_PASSED_TO_P_FORMAT = "unsupported format string passed to %p.__format__";
 }