Make inspecting and printing non-python numbers work

Truffle debugger uses inspection facilities provided by the language
that constructed given object. But primitive types are an exception and
their inspection is always done using the primary language's facilities.
Therefore even though we never expose some numeric types such as float,
the debugger can still request `PythonLanguage` to inspect them when
processing foreign objects that contain them (for example a Java
`float[]` array). Add basic inspection facilities for those types.

Author: msimacek

graalpython/com.oracle.graal.python.test/src/com/oracle/graal/python/test/debug/PythonDebugTest.java

@@ -64,6 +64,7 @@
 
 import com.oracle.graal.python.test.PythonTests;
 import com.oracle.truffle.api.debug.Breakpoint;
+import com.oracle.truffle.api.debug.DebugScope;
 import com.oracle.truffle.api.debug.DebugStackFrame;
 import com.oracle.truffle.api.debug.DebugValue;
 import com.oracle.truffle.api.debug.DebuggerSession;
@@ -404,6 +405,51 @@ public void testGettersSetters() throws Throwable {
         }
     }
 
+    @Test
+    public void testInspectJavaArray() throws Throwable {
+        final Source source = Source.newBuilder("python", "" +
+                        "import java\n" +
+                        "a_int = java.type('int[]')(3)\n" +
+                        "a_long = java.type('long[]')(3)\n" +
+                        "a_short = java.type('short[]')(3)\n" +
+                        "a_byte = java.type('byte[]')(3)\n" +
+                        "a_float = java.type('float[]')(3)\n" +
+                        "a_double = java.type('double[]')(3)\n" +
+                        "a_char = java.type('char[]')(3)\n" +
+                        "print()\n" +
+                        "\n", "testInspectJavaArray.py").buildLiteral();
+        try (DebuggerSession session = tester.startSession()) {
+            session.install(Breakpoint.newBuilder(DebuggerTester.getSourceImpl(source)).lineIs(9).build());
+            tester.startEval(source);
+            expectSuspended((SuspendedEvent event) -> {
+                DebugScope globalScope = session.getTopScope("python");
+                DebugValue intValue = globalScope.getDeclaredValue("a_int").getArray().get(0);
+                // It's up to Truffle to decide which language it uses for inspection of primitives,
+                // we should be fine as long as this doesn't throw an exception
+                intValue.getMetaObject();
+                assertEquals("0", intValue.as(String.class));
+                DebugValue longValue = globalScope.getDeclaredValue("a_long").getArray().get(0);
+                longValue.getMetaObject();
+                assertEquals("0", longValue.as(String.class));
+                DebugValue shortValue = globalScope.getDeclaredValue("a_short").getArray().get(0);
+                shortValue.getMetaObject();
+                assertEquals("0", shortValue.as(String.class));
+                DebugValue byteValue = globalScope.getDeclaredValue("a_byte").getArray().get(0);
+                byteValue.getMetaObject();
+                assertEquals("0", byteValue.as(String.class));
+                DebugValue floatValue = globalScope.getDeclaredValue("a_float").getArray().get(0);
+                floatValue.getMetaObject();
+                assertEquals("0.0", floatValue.as(String.class));
+                DebugValue doubleValue = globalScope.getDeclaredValue("a_double").getArray().get(0);
+                doubleValue.getMetaObject();
+                assertEquals("0.0", doubleValue.as(String.class));
+                DebugValue charValue = globalScope.getDeclaredValue("a_char").getArray().get(0);
+                charValue.getMetaObject();
+                assertEquals("\0", charValue.as(String.class));
+            });
+        }
+    }
+
     @Test
     public void testSourceFileURI() throws Throwable {
         if (System.getProperty("os.name").toLowerCase().contains("mac")) {

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/PythonLanguage.java

@@ -32,6 +32,9 @@
 import java.util.function.Supplier;
 import java.util.logging.Level;
 
+import org.graalvm.options.OptionDescriptors;
+import org.graalvm.options.OptionValues;
+
 import com.oracle.graal.python.builtins.Python3Core;
 import com.oracle.graal.python.builtins.objects.PEllipsis;
 import com.oracle.graal.python.builtins.objects.PNone;
@@ -94,9 +97,6 @@
 import com.oracle.truffle.api.source.Source.SourceBuilder;
 import com.oracle.truffle.api.source.SourceSection;
 
-import org.graalvm.options.OptionDescriptors;
-import org.graalvm.options.OptionValues;
-
 @TruffleLanguage.Registration(id = PythonLanguage.ID, //
                 name = PythonLanguage.NAME, //
                 version = PythonLanguage.VERSION, //
@@ -334,6 +334,10 @@ protected boolean isObjectOfLanguage(Object object) {
         return object instanceof PythonAbstractObject;
     }
 
+    private boolean isForeignPrimitive(Object value) {
+        return value instanceof Float || value instanceof Short || value instanceof Character || value instanceof Byte;
+    }
+
     @Override
     protected Object findMetaObject(PythonContext context, Object value) {
         if (value != null) {
@@ -342,6 +346,9 @@ protected Object findMetaObject(PythonContext context, Object value) {
             } else if (PGuards.isNativeObject(value)) {
                 // TODO(fa): we could also use 'GetClassNode.getItSlowPath(value)' here
                 return null;
+            } else if (isForeignPrimitive(value)) {
+                // these only appear when inspecting foreign data structures
+                return null;
             } else if (value instanceof PythonAbstractObject ||
                             value instanceof Number ||
                             value instanceof String ||
@@ -454,6 +461,11 @@ protected SourceSection findSourceLocation(PythonContext context, Object value)
 
     @Override
     protected String toString(PythonContext context, Object value) {
+        if (isForeignPrimitive(value)) {
+            // these only appear when inspecting foreign data structures, so they shouldn't get
+            // processed by python code
+            return value.toString();
+        }
         if (PythonOptions.getFlag(context, PythonOptions.UseReprForPrintString)) {
             final PythonModule builtins = context.getBuiltins();
             if (builtins != null) {