Pretending WithWarnings isException (#9840)

engine/runtime-integration-tests/src/test/java/org/enso/interpreter/test/BinaryDispatchTest.java

@@ -291,10 +291,14 @@ public class BinaryDispatchTest extends TestBase {
     }
   }
 
-  private static void assertContains(String expected, String actual) {
+  static void assertContains(String expected, String actual) {
-    if (actual.contains(expected)) {
+    assertContains("Expecting", expected, actual);
+  }
+
+  static void assertContains(String msg, String expected, String actual) {
+    if (actual != null && actual.contains(expected)) {
       return;
     }
-    fail("Expecting " + expected + " in " + actual);
+    fail(msg + " " + expected + " in " + actual);
   }
 }

engine/runtime-integration-tests/src/test/java/org/enso/interpreter/test/MetaIsATest.java

@@ -20,6 +20,7 @@ import org.junit.Test;
 public class MetaIsATest extends TestBase {
   private static Context ctx;
   private static Value isACheck;
+  private static Value warningCheck;
   private static ValuesGenerator generator;
 
   @BeforeClass
@@ -30,9 +31,10 @@ public class MetaIsATest extends TestBase {
         Source.newBuilder(
                 "enso",
                 """
-    import Standard.Base.Meta
+    from Standard.Base import Meta, Warning
 
     check x y = Meta.is_a x y
+    check_warning x = Warning.has_warnings x
     """,
                 "check.enso")
             .uri(uri)
@@ -40,6 +42,7 @@ public class MetaIsATest extends TestBase {
 
     var module = ctx.eval(src);
     isACheck = module.invokeMember("eval_expression", "check");
+    warningCheck = module.invokeMember("eval_expression", "check_warning");
     assertTrue("it is a function", isACheck.canExecute());
   }
 
@@ -283,9 +286,22 @@ public class MetaIsATest extends TestBase {
       Value caseOf, Value v, Value t, StringBuilder f, ValuesGenerator g) {
     var test = caseOf.execute(v);
     if (test.isException()) {
+      // if a generated value isException (from interop point of view)
+      // then it is either DataflowError or Warning
+      var vMeta = v.getMetaObject();
+      if (g.typeError().equals(vMeta)) {
         assertEquals("DataFlowError in", g.typeError(), v.getMetaObject());
         assertEquals("DataFlowError out", g.typeError(), test.getMetaObject());
+        // end the test here as DataflowError doesn't represent a value
         return;
+      } else {
+        // check if Warning.has_warnings is true
+        var wv = warningCheck.execute(v);
+        var wTest = warningCheck.execute(test);
+        assertTrue("Warning in", wv.asBoolean());
+        assertTrue("Warning out", wTest.asBoolean());
+        // but continue with the rest of the test, as Warning still represents a value
+      }
     }
     assertTrue("Expecting 0 or 1 result: " + test + " for " + v, test.isNumber());
     var testBool = test.asInt() == 1;

engine/runtime-integration-tests/src/test/java/org/enso/interpreter/test/WarningsTest.java

@@ -1,6 +1,8 @@
 package org.enso.interpreter.test;
 
+import static org.enso.interpreter.test.BinaryDispatchTest.assertContains;
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
 import static org.junit.Assert.fail;
 
 import org.enso.common.LanguageInfo;
@@ -10,6 +12,8 @@ import org.enso.interpreter.runtime.error.Warning;
 import org.enso.interpreter.runtime.error.WarningsLibrary;
 import org.enso.interpreter.runtime.error.WithWarnings;
 import org.graalvm.polyglot.Context;
+import org.graalvm.polyglot.PolyglotException;
+import org.graalvm.polyglot.Value;
 import org.junit.AfterClass;
 import org.junit.Assert;
 import org.junit.BeforeClass;
@@ -18,16 +22,28 @@ import org.junit.Test;
 public class WarningsTest extends TestBase {
 
   private static Context ctx;
+  private static ValuesGenerator generator;
+  private static Value wrap;
   private static EnsoContext ensoContext;
 
   @BeforeClass
   public static void initEnsoContext() {
     ctx = createDefaultContext();
+    generator = ValuesGenerator.create(ctx, ValuesGenerator.Language.ENSO);
     ensoContext =
         (EnsoContext)
             ctx.getBindings(LanguageInfo.ID)
                 .invokeMember(MethodNames.TopScope.LEAK_CONTEXT)
                 .asHostObject();
+    var module =
+        ctx.eval(
+            "enso",
+            """
+    from Standard.Base import Warning
+
+    wrap msg value = Warning.attach msg value
+    """);
+    wrap = module.invokeMember(MethodNames.Module.EVAL_EXPRESSION, "wrap");
   }
 
   @AfterClass
@@ -65,4 +81,75 @@ public class WarningsTest extends TestBase {
     }
     fail("One shall not be created WithWarnings without any warnings " + without);
   }
+
+  @Test
+  public void warningIsAnException() {
+    var warning42 = wrap.execute("warn:1", 42);
+    var warningHi = wrap.execute("warn:2", "Hi");
+
+    assertTrue("value is a number", warning42.isNumber());
+    assertTrue("value is Int", warning42.fitsInInt());
+    assertEquals(42, warning42.asInt());
+
+    assertTrue("value2 is a text", warningHi.isString());
+    assertTrue("value2 not a number", warning42.isNumber());
+    assertEquals("Hi", warningHi.asString());
+
+    assertTrue("value1 with warning is also an exception", warning42.isException());
+    assertTrue("value2 with warning is also an exception", warningHi.isException());
+
+    try {
+      warning42.throwException();
+      fail("Shouldn't reach here");
+    } catch (PolyglotException ex) {
+      assertEquals("warn:1", ex.getMessage());
+    }
+
+    var warningMulti = wrap.execute("warn:3", warning42);
+    assertTrue("multi value is a number", warningMulti.isNumber());
+    assertTrue("multi value is Int", warningMulti.fitsInInt());
+    assertEquals(42, warningMulti.asInt());
+
+    assertTrue("multi vlaue with warning is also an exception", warningMulti.isException());
+
+    try {
+      warningMulti.throwException();
+      fail("Shouldn't reach here");
+    } catch (PolyglotException ex) {
+      assertContains("warn:1", ex.getMessage());
+      assertContains("warn:3", ex.getMessage());
+    }
+  }
+
+  @Test
+  public void allWarningsAreExceptions() throws Exception {
+    for (var v : generator.allValues()) {
+      if (v.isNull() || v.isBoolean()) {
+        continue;
+      }
+      assertWarningsForAType(v);
+    }
+  }
+
+  private void assertWarningsForAType(Value v) {
+    var type = v.getMetaObject();
+
+    var warning1 = wrap.execute("warn:once", v);
+    var warning2 = wrap.execute("warn:twice", warning1);
+
+    var warningType = warning2.getMetaObject();
+    assertEquals("Types without and with warnings are the same", type, warningType);
+    assertTrue("It is an exception. Type: " + type, warning2.isException());
+    try {
+      warning2.throwException();
+    } catch (PolyglotException ex) {
+      if (ex.getMessage() == null) {
+        assertEquals(generator.typeError(), type);
+        assertEquals(generator.typeError(), warningType);
+      } else {
+        assertContains("Warning found for " + type, "warn:once", ex.getMessage());
+        assertContains("Warning found for " + type, "warn:twice", ex.getMessage());
+      }
+    }
+  }
 }

engine/runtime/src/main/java/org/enso/interpreter/node/callable/InteropMethodCallNode.java

@@ -32,6 +32,10 @@ public abstract class InteropMethodCallNode extends Node {
     return InteropMethodCallNodeGen.create();
   }
 
+  public static InteropMethodCallNode getUncached() {
+    return InteropMethodCallNodeGen.getUncached();
+  }
+
   /**
    * Calls the method with given state and arguments.
    *

engine/runtime/src/main/java/org/enso/interpreter/runtime/data/text/Text.java

@@ -27,6 +27,7 @@ import org.enso.polyglot.common_utils.Core_Text_Utils;
 @ExportLibrary(TypesLibrary.class)
 public final class Text implements EnsoObject {
   private static final Lock LOCK = new ReentrantLock();
+  private static final Text EMPTY = new Text("");
   private volatile Object contents;
   private volatile int length = -1;
   private volatile FcdNormalized fcdNormalized = FcdNormalized.UNKNOWN;
@@ -98,6 +99,10 @@ public final class Text implements EnsoObject {
     return false;
   }
 
+  public static Text empty() {
+    return EMPTY;
+  }
+
   /**
    * Wraps a string in an instance of Text.
    *

engine/runtime/src/main/java/org/enso/interpreter/runtime/error/WithWarnings.java

@@ -1,7 +1,10 @@
 package org.enso.interpreter.runtime.error;
 
 import com.oracle.truffle.api.CompilerDirectives;
+import com.oracle.truffle.api.dsl.Bind;
 import com.oracle.truffle.api.dsl.Cached.Shared;
+import com.oracle.truffle.api.interop.ArityException;
+import com.oracle.truffle.api.interop.InteropLibrary;
 import com.oracle.truffle.api.interop.TruffleObject;
 import com.oracle.truffle.api.interop.UnsupportedMessageException;
 import com.oracle.truffle.api.library.CachedLibrary;
@@ -10,21 +13,43 @@ import com.oracle.truffle.api.library.ExportMessage;
 import com.oracle.truffle.api.library.Message;
 import com.oracle.truffle.api.library.ReflectionLibrary;
 import com.oracle.truffle.api.nodes.Node;
+import org.enso.interpreter.node.callable.InteropMethodCallNode;
 import org.enso.interpreter.runtime.EnsoContext;
+import org.enso.interpreter.runtime.callable.UnresolvedSymbol;
 import org.enso.interpreter.runtime.data.ArrayRope;
 import org.enso.interpreter.runtime.data.EnsoObject;
 import org.enso.interpreter.runtime.data.Type;
+import org.enso.interpreter.runtime.data.text.Text;
 import org.enso.interpreter.runtime.library.dispatch.TypesLibrary;
+import org.enso.interpreter.runtime.state.State;
 import org.graalvm.collections.EconomicSet;
 import org.graalvm.collections.Equivalence;
 
+/**
+ * Represents a typical Enso <em>value with warnings</em>. As much of care as possible is taken to
+ * delegate all operations to the underlaying {@code value}. Warnings are considered {@link
+ * InteropLibrary#isException exceptional values} - e.g. one can check for them in Java polyglot
+ * code as:
+ *
+ * <pre>
+ *  Value value = ...;
+ *  if (value.fitsInLong() && value.isException()) {
+ *    // probably an Integer with a warning
+ *    try {
+ *      warningMulti.throwException();
+ *    } catch (PolyglotException ex) {
+ *      System.out.println("Warnings attached to " + value.asLong() + " are " + ex.getMessage());
+ *    }
+ *  }
+ * </pre>
+ */
 @ExportLibrary(TypesLibrary.class)
 @ExportLibrary(WarningsLibrary.class)
 @ExportLibrary(ReflectionLibrary.class)
+@ExportLibrary(value = InteropLibrary.class, delegateTo = "value")
 public final class WithWarnings implements EnsoObject {
-
+  final Object value;
   private final EconomicSet<Warning> warnings;
-  private final Object value;
 
   private final boolean limitReached;
   private final int maxWarnings;
@@ -191,6 +216,29 @@ public final class WithWarnings implements EnsoObject {
     }
   }
 
+  @CompilerDirectives.TruffleBoundary
+  private PanicException asException(Node where) {
+    var rawWarn = this.getWarnings(where, false, WarningsLibrary.getUncached());
+    var ctx = EnsoContext.get(where);
+    var scopeOfAny = ctx.getBuiltins().any().getDefinitionScope();
+    var toText = UnresolvedSymbol.build("to_text", scopeOfAny);
+    var node = InteropMethodCallNode.getUncached();
+    var state = State.create(ctx);
+
+    var text = Text.empty();
+    for (var w : rawWarn) {
+      try {
+        var wText = node.execute(toText, state, new Object[] {w});
+        if (wText instanceof Text t) {
+          text = text.add(t);
+        }
+      } catch (ArityException e) {
+        throw ctx.raiseAssertionPanic(where, null, e);
+      }
+    }
+    return new PanicException(text, where);
+  }
+
   @ExportMessage
   Object send(Message message, Object[] args, @CachedLibrary(limit = "3") ReflectionLibrary lib)
       throws Exception {
@@ -250,6 +298,16 @@ public final class WithWarnings implements EnsoObject {
     return true;
   }
 
+  @ExportMessage
+  boolean isException() {
+    return true;
+  }
+
+  @ExportMessage
+  RuntimeException throwException(@Bind("$node") Node node) throws UnsupportedMessageException {
+    throw asException(node);
+  }
+
   public static class WarningEquivalence extends Equivalence {
 
     @Override