[GR-19264] Fix message-less AssertionError args count

PullRequest: graalpython/887

Author: qunaibit

graalpython/com.oracle.graal.python.test/src/com/oracle/graal/python/test/grammar/TryTests.java

@@ -192,4 +192,17 @@ public void tryGrammarError() {
         assertLastLineErrorContains("SyntaxError", "try: 1+1\n");
         assertLastLineErrorContains("SyntaxError", "try:\n 1+1\n");
     }
+
+    @Test
+    public void tryZeroArgLen() {
+        assertPrints("0\n", "try:\n" +
+                        "   assert False\n" +
+                        "except AssertionError as e:\n" +
+                        "   print(len(e.args))\n");
+
+        assertPrints("1\n", "try:\n" +
+                        "   assert False, \"\"\n" +
+                        "except AssertionError as e:\n" +
+                        "   print(len(e.args))\n");
+    }
 }

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/objects/exception/BaseExceptionBuiltins.java

@@ -109,11 +109,16 @@ private String getFormattedMessage(String format, Object... args) {
 
         @Specialization(guards = "isNoValue(none)")
         public Object args(PBaseException self, @SuppressWarnings("unused") PNone none,
-                        @Cached("createBinaryProfile()") ConditionProfile nullArgsProfile) {
+                        @Cached("createBinaryProfile()") ConditionProfile nullArgsProfile,
+                        @Cached("createBinaryProfile()") ConditionProfile hasMessageFormat) {
             PTuple args = self.getArgs();
             if (nullArgsProfile.profile(args == null)) {
-                // lazily format the exception message:
-                args = factory().createTuple(new Object[]{getFormattedMessage(self.getMessageFormat(), self.getMessageArgs())});
+                if (hasMessageFormat.profile(!self.hasMessageFormat())) {
+                    args = factory().createTuple(new Object[0]);
+                } else {
+                    // lazily format the exception message:
+                    args = factory().createTuple(new Object[]{getFormattedMessage(self.getMessageFormat(), self.getMessageArgs())});
+                }
                 self.setArgs(args);
             }
             return args;

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/objects/exception/PBaseException.java

@@ -67,6 +67,7 @@ public final class PBaseException extends PythonObject {
     private PTuple args; // can be null for lazily generated message
 
     // in case of lazily generated messages, these will be used to construct the message:
+    private final boolean hasMessageFormat;
     private final String messageFormat;
     private final Object[] messageArgs;
 
@@ -79,13 +80,15 @@ public final class PBaseException extends PythonObject {
     public PBaseException(LazyPythonClass cls, PTuple args) {
         super(cls);
         this.args = args;
+        this.hasMessageFormat = false;
         this.messageFormat = null;
         this.messageArgs = null;
     }
 
     public PBaseException(LazyPythonClass cls, String format, Object[] args) {
         super(cls);
         this.args = null;
+        this.hasMessageFormat = true;
         this.messageFormat = format;
         this.messageArgs = args;
     }
@@ -144,6 +147,10 @@ public String getMessageFormat() {
         return messageFormat;
     }
 
+    public boolean hasMessageFormat() {
+        return hasMessageFormat;
+    }
+
     public Object[] getMessageArgs() {
         // clone message args to ensure that they stay unmodified
         return messageArgs.clone();

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/objects/str/StringNodes.java

@@ -46,7 +46,6 @@
 import java.util.Arrays;
 
 import com.oracle.graal.python.builtins.PythonBuiltinClassType;
-import com.oracle.graal.python.builtins.objects.PNone;
 import com.oracle.graal.python.builtins.objects.cext.CExtNodes.PCallCapiFunction;
 import com.oracle.graal.python.builtins.objects.cext.CExtNodes.ToSulongNode;
 import com.oracle.graal.python.builtins.objects.cext.NativeCAPISymbols;
@@ -204,7 +203,7 @@ static String doConvert(Object self, String errMsgFormat, Object[] errMsgArgs,
                         @Cached PRaiseNode raiseNode) {
             String result = castToJavaStringNode.execute(self);
             if (errorProfile.profile(result == null)) {
-                throw raiseNode.execute(PythonBuiltinClassType.TypeError, PNone.NO_VALUE, errMsgFormat, errMsgArgs);
+                throw raiseNode.raise(PythonBuiltinClassType.TypeError, errMsgFormat, errMsgArgs);
             }
             return result;
         }

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/nodes/statement/AssertNode.java

@@ -89,7 +89,7 @@ public void executeVoid(VirtualFrame frame) {
     }
 
     private PException assertionFailed(VirtualFrame frame) {
-        String assertionMessage = "";
+        String assertionMessage = null;
         if (message != null) {
             try {
                 Object messageObj = message.execute(frame);
@@ -113,6 +113,9 @@ private PException assertionFailed(VirtualFrame frame) {
             CompilerDirectives.transferToInterpreterAndInvalidate();
             raise = insert(PRaiseNode.create());
         }
+        if (assertionMessage == null) {
+            return raise.raise(AssertionError);
+        }
         return raise.raise(AssertionError, assertionMessage);
     }