[GR-4133] Fix: NPE and UnsupportedSpecializationException when retrieving arguments from RScope.

com.oracle.truffle.r.runtime/src/com/oracle/truffle/r/runtime/env/RScope.java

@@ -36,6 +36,7 @@ import com.oracle.truffle.api.nodes.Node;
 import com.oracle.truffle.r.runtime.ArgumentsSignature;
 import com.oracle.truffle.r.runtime.RArguments;
 import com.oracle.truffle.r.runtime.RInternalError;
+import com.oracle.truffle.r.runtime.context.RContext;
 import com.oracle.truffle.r.runtime.data.RFunction;
 import com.oracle.truffle.r.runtime.data.RStringVector;
 import com.oracle.truffle.r.runtime.env.REnvironment.PutException;
@@ -64,8 +65,20 @@ public final class RScope extends AbstractScope {
 
     @Override
     protected String getName() {
-        // TODO promises (= closure)
-        return "function";
+        // just to be sure
+        if (env == REnvironment.emptyEnv()) {
+            return "empty environment";
+        }
+
+        assert env.getFrame() != null;
+        RFunction function = RArguments.getFunction(env.getFrame());
+        if (function != null) {
+            String name = function.getName();
+            return "function environment" + (name != null ? " for function " + name : "");
+        } else {
+            String name = env.getName();
+            return "explicit environment" + (name != null ? ": " + name : "");
+        }
     }
 
     @Override
@@ -103,8 +116,20 @@ public final class RScope extends AbstractScope {
     }
 
     private static String[] collectArgs(REnvironment env) {
-        ArgumentsSignature signature = RArguments.getSignature(env.getFrame());
-        return signature.getNames();
+
+        if (env != REnvironment.emptyEnv()) {
+            assert RArguments.isRFrame(env.getFrame());
+            RFunction f = RArguments.getFunction(env.getFrame());
+            if (f != null) {
+                return RContext.getRRuntimeASTAccess().getArgumentsSignature(f).getNames();
+            } else {
+                ArgumentsSignature suppliedSignature = RArguments.getSuppliedSignature(env.getFrame());
+                if (suppliedSignature != null) {
+                    return suppliedSignature.getNames();
+                }
+            }
+        }
+        return new String[0];
     }
 
     public static RScope createScope(Node node, Frame frame) {
@@ -274,7 +299,7 @@ public final class RScope extends AbstractScope {
 
         @Override
         public ForeignAccess getForeignAccess() {
-            return VariableNamesMessageResolutionForeign.ACCESS;
+            return ArgumentNamesMessageResolutionForeign.ACCESS;
         }
 
         public static boolean isInstance(TruffleObject obj) {

com.oracle.truffle.r.test/src/com/oracle/truffle/r/test/tck/FastRDebugTest.java

@@ -29,6 +29,7 @@ import static org.junit.Assert.assertTrue;
 
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
+import java.util.Arrays;
 import java.util.HashSet;
 import java.util.LinkedList;
 import java.util.Set;
@@ -320,6 +321,39 @@ public class FastRDebugTest {
         assertExecutedOK();
     }
 
+    @Test
+    public void testScopeArguments() throws Throwable {
+        final Source source = RSource.fromTextInternal("main <- function(a, b, c, d) {\n" +
+                        "   x <- 10L\n" +
+                        "}\n" +
+                        "closure <- function() {\n" +
+                        "   x <<- 123L\n" +
+                        "   x\n" +
+                        "}\n",
+
+                        RSource.Internal.DEBUGTEST_DEBUG);
+        engine.eval(source);
+
+        // @formatter:on
+        run.addLast(() -> {
+            assertNull(suspendedEvent);
+            assertNotNull(debuggerSession);
+            debuggerSession.suspendNextExecution();
+        });
+
+        assertArguments(1, "main(1, 2, 3, 4)");
+
+        stepInto(1);
+        assertArguments(2, "x <- 10L", "a", "b", "c", "d");
+        continueExecution();
+        performWork();
+
+        final Source evalSource = RSource.fromTextInternal("main(1, 2, 3, 4)\n", RSource.Internal.DEBUGTEST_EVAL);
+        engine.eval(evalSource);
+
+        assertExecutedOK();
+    }
+
     @Test
     public void testChangedScopeChain() throws Throwable {
         final Source source = RSource.fromTextInternal("main <- function(e) {\n" +
@@ -461,6 +495,35 @@ public class FastRDebugTest {
         });
     }
 
+    private void assertArguments(final int line, final String code, final String... expectedArgs) {
+        run.addLast(() -> {
+            try {
+                final DebugStackFrame frame = suspendedEvent.getTopStackFrame();
+
+                DebugScope scope = frame.getScope();
+
+                Set<String> actualIdentifiers = new HashSet<>();
+                scope.getArguments().forEach((x) -> actualIdentifiers.add(x.getName()));
+
+                assertEquals(line + ": " + code, expectedArgs.length, actualIdentifiers.size());
+
+                Set<String> expectedIds = new HashSet<>(Arrays.asList(expectedArgs));
+                Assert.assertEquals(expectedIds, actualIdentifiers);
+
+                if (!run.isEmpty()) {
+                    run.removeFirst().run();
+                }
+            } catch (RuntimeException | Error e) {
+
+                final DebugStackFrame frame = suspendedEvent.getTopStackFrame();
+                frame.forEach(var -> {
+                    System.out.println(var);
+                });
+                throw e;
+            }
+        });
+    }
+
     private void compareScope(final int line, final String code, boolean includeAncestors, boolean completeMatch, final Object[] expectedFrame) {
         final DebugStackFrame frame = suspendedEvent.getTopStackFrame();