Improve the handling of dataflow errors (#1433)

README.md

@@ -21,7 +21,7 @@
   <br/>
 </p>
 
-### Get insights you can act on, fast.
+### Get insights you can act on, fast
 
 <p>
   <a href="http://chat.enso.org">

distribution/std-lib/Test/src/Test.enso

@@ -48,8 +48,17 @@ Any.should verb argument = verb Verbs this argument
 ## Fail a test with the given message.
 fail message = Panic.throw (Failure message)
 
-## Expect a function to fail with the provided error.
-expect_fail_with ~action matcher =
+## Expect a function to fail with the provided dataflow error.
+expect_error_with ~action matcher =
+    result = action
+    fail_msg = "Expected an error " + matcher.to_text + "but none occurred."
+    if result.is_error.not then here.fail fail_msg else
+        caught = result.catch x->x
+        if caught.is_a matcher then Nothing else
+            here.fail ("Unexpected error " + caught.to_text + " thrown.")
+
+## Expect a function to fail with the provided panic.
+expect_panic_with ~action matcher =
     res = Panic.recover action
     case res of
         _ -> here.fail ("Expected a " + matcher.to_text + " to be thrown, but the action succeeded.")

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

@@ -15,6 +15,7 @@
 import org.enso.interpreter.runtime.callable.function.Function;
 import org.enso.interpreter.runtime.error.DataflowError;
 import org.enso.interpreter.runtime.error.NotInvokableException;
+import org.enso.interpreter.runtime.error.PanicSentinel;
 import org.enso.interpreter.runtime.state.Stateful;
 
 /**
@@ -93,6 +94,32 @@ Stateful invokeConstructor(
         invokeFunctionNode);
   }
 
+  @Specialization
+  Stateful invokeDataflowError(
+      DataflowError error,
+      MaterializedFrame callerFrame,
+      Object state,
+      Object[] arguments,
+      CallArgumentInfo[] schema,
+      InvokeCallableNode.DefaultsExecutionMode defaultsExecutionMode,
+      InvokeCallableNode.ArgumentsExecutionMode argumentsExecutionMode,
+      BaseNode.TailStatus isTail) {
+    return new Stateful(state, error);
+  }
+
+  @Specialization
+  Stateful invokePanicSentinel(
+      PanicSentinel sentinel,
+      MaterializedFrame callerFrame,
+      Object state,
+      Object[] arguments,
+      CallArgumentInfo[] schema,
+      InvokeCallableNode.DefaultsExecutionMode defaultsExecutionMode,
+      InvokeCallableNode.ArgumentsExecutionMode argumentsExecutionMode,
+      BaseNode.TailStatus isTail) {
+    throw sentinel;
+  }
+
   @Specialization
   public Stateful invokeDynamicSymbol(
       UnresolvedSymbol symbol,

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

@@ -1,5 +1,6 @@
 package org.enso.interpreter.node.callable;
 
+import com.oracle.truffle.api.CompilerDirectives;
 import com.oracle.truffle.api.dsl.Cached;
 import com.oracle.truffle.api.dsl.GenerateUncached;
 import com.oracle.truffle.api.dsl.ReportPolymorphism;
@@ -28,6 +29,7 @@
 import org.enso.interpreter.runtime.data.Array;
 import org.enso.interpreter.runtime.data.text.Text;
 import org.enso.interpreter.runtime.error.DataflowError;
+import org.enso.interpreter.runtime.error.PanicSentinel;
 import org.enso.interpreter.runtime.number.EnsoBigInteger;
 import org.enso.interpreter.runtime.state.Stateful;
 
@@ -281,6 +283,20 @@ Stateful doDataflowError(
     }
   }
 
+  @Specialization
+  Stateful doPanicSentinel(
+      MaterializedFrame frame,
+      Object state,
+      UnresolvedSymbol symbol,
+      PanicSentinel _this,
+      Object[] arguments,
+      CallArgumentInfo[] schema,
+      InvokeCallableNode.DefaultsExecutionMode defaultsExecutionMode,
+      InvokeCallableNode.ArgumentsExecutionMode argumentsExecutionMode,
+      BaseNode.TailStatus isTail) {
+    throw _this;
+  }
+
   @Specialization
   Stateful doArray(
       MaterializedFrame frame,

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

@@ -20,6 +20,7 @@
 import org.enso.interpreter.runtime.callable.function.Function;
 import org.enso.interpreter.runtime.error.DataflowError;
 import org.enso.interpreter.runtime.error.NotInvokableException;
+import org.enso.interpreter.runtime.error.PanicSentinel;
 import org.enso.interpreter.runtime.state.Stateful;
 
 /**
@@ -142,6 +143,18 @@ Stateful invokeConstructor(
     return invokeFunction(constructor.getConstructorFunction(), callerFrame, state, arguments);
   }
 
+  @Specialization
+  Stateful invokeDataflowError(
+      DataflowError error, VirtualFrame callerFrame, Object state, Object[] arguments) {
+    return new Stateful(state, error);
+  }
+
+  @Specialization
+  Stateful invokePanicSentinel(
+      PanicSentinel sentinel, VirtualFrame callerFrame, Object state, Object[] arguments) {
+    throw sentinel;
+  }
+
   @Specialization
   public Stateful invokeDynamicSymbol(
       UnresolvedSymbol symbol, VirtualFrame callerFrame, Object state, Object[] arguments) {

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

@@ -1,12 +1,12 @@
 package org.enso.interpreter.node.callable;
 
-import com.oracle.truffle.api.CompilerDirectives;
 import com.oracle.truffle.api.dsl.Cached;
 import com.oracle.truffle.api.dsl.Specialization;
 import com.oracle.truffle.api.frame.VirtualFrame;
 import com.oracle.truffle.api.nodes.Node;
 import com.oracle.truffle.api.profiles.ConditionProfile;
 import com.oracle.truffle.api.source.SourceSection;
+import java.util.UUID;
 import org.enso.interpreter.node.BaseNode;
 import org.enso.interpreter.node.callable.dispatch.InvokeFunctionNode;
 import org.enso.interpreter.node.callable.resolver.ArrayResolverNode;
@@ -28,11 +28,10 @@
 import org.enso.interpreter.runtime.data.Array;
 import org.enso.interpreter.runtime.data.text.Text;
 import org.enso.interpreter.runtime.error.DataflowError;
+import org.enso.interpreter.runtime.error.PanicSentinel;
 import org.enso.interpreter.runtime.number.EnsoBigInteger;
 import org.enso.interpreter.runtime.state.Stateful;
 
-import java.util.UUID;
-
 public abstract class InvokeMethodNode extends BaseNode {
   private @Child InvokeFunctionNode invokeFunctionNode;
   private final ConditionProfile errorProfile = ConditionProfile.createCountingProfile();
@@ -181,6 +180,16 @@ Stateful doDataflowError(
     }
   }
 
+  @Specialization
+  Stateful doPanicSentinel(
+      VirtualFrame frame,
+      Object state,
+      UnresolvedSymbol symbol,
+      PanicSentinel _this,
+      Object[] arguments) {
+    throw _this;
+  }
+
   @Specialization
   Stateful doArray(
       VirtualFrame frame,

engine/runtime/src/main/java/org/enso/interpreter/node/controlflow/caseexpr/CaseNode.java

@@ -14,6 +14,7 @@
 import org.enso.interpreter.runtime.Context;
 import org.enso.interpreter.runtime.error.DataflowError;
 import org.enso.interpreter.runtime.error.PanicException;
+import org.enso.interpreter.runtime.error.PanicSentinel;
 import org.enso.interpreter.runtime.type.TypesGen;
 
 /**
@@ -58,6 +59,19 @@ public Object doError(VirtualFrame frame, DataflowError error) {
     return error;
   }
 
+  /**
+   * Rethrows a panic sentinel if it encounters one.
+   *
+   * @param frame the stack frame in which to execute
+   * @param sentinel the sentinel being matched against
+   * @return nothing
+   */
+  @Specialization
+  public Object doPanicSentinel(VirtualFrame frame, PanicSentinel sentinel) {
+    CompilerDirectives.transferToInterpreter();
+    throw sentinel;
+  }
+
   /**
    * Executes the case expression.
    *
@@ -66,7 +80,7 @@ public Object doError(VirtualFrame frame, DataflowError error) {
    * @param ctx the language context reference
    * @return the result of executing the case expression on {@code object}
    */
-  @Specialization(guards = "!isDataflowError(object)")
+  @Specialization(guards = {"!isDataflowError(object)", "!isPanicSentinel(object)"})
   @ExplodeLoop
   public Object doMatch(
       VirtualFrame frame,
@@ -92,6 +106,10 @@ boolean isDataflowError(Object error) {
     return TypesGen.isDataflowError(error);
   }
 
+  boolean isPanicSentinel(Object sentinel) {
+    return TypesGen.isPanicSentinel(sentinel);
+  }
+
   /* Note [Branch Selection Control Flow]
    * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    * Truffle provides no easy way to return control flow from multiple paths. This is entirely due

engine/runtime/src/main/java/org/enso/interpreter/node/expression/atom/InstantiateNode.java

@@ -4,6 +4,7 @@
 import com.oracle.truffle.api.frame.VirtualFrame;
 import com.oracle.truffle.api.nodes.ExplodeLoop;
 import com.oracle.truffle.api.nodes.NodeInfo;
+import com.oracle.truffle.api.profiles.BranchProfile;
 import com.oracle.truffle.api.profiles.ConditionProfile;
 import org.enso.interpreter.node.ExpressionNode;
 import org.enso.interpreter.runtime.callable.atom.AtomConstructor;
@@ -18,13 +19,16 @@ public class InstantiateNode extends ExpressionNode {
   private final AtomConstructor constructor;
   private @Children ExpressionNode[] arguments;
   private @CompilationFinal(dimensions = 1) ConditionProfile[] profiles;
+  private @CompilationFinal(dimensions = 1) BranchProfile[] sentinelProfiles;
 
   InstantiateNode(AtomConstructor constructor, ExpressionNode[] arguments) {
     this.constructor = constructor;
     this.arguments = arguments;
     this.profiles = new ConditionProfile[arguments.length];
+    this.sentinelProfiles = new BranchProfile[arguments.length];
     for (int i = 0; i < arguments.length; ++i) {
       this.profiles[i] = ConditionProfile.createCountingProfile();
+      this.sentinelProfiles[i] = BranchProfile.create();
     }
   }
 
@@ -51,8 +55,17 @@ public static InstantiateNode build(AtomConstructor constructor, ExpressionNode[
   public Object executeGeneric(VirtualFrame frame) {
     Object[] argumentValues = new Object[arguments.length];
     for (int i = 0; i < arguments.length; i++) {
+      ConditionProfile profile = profiles[i];
+      BranchProfile sentinelProfile = sentinelProfiles[i];
       Object argument = arguments[i].executeGeneric(frame);
-      argumentValues[i] = argument;
+      if (profile.profile(TypesGen.isDataflowError(argument))) {
+        return argument;
+      } else if (TypesGen.isPanicSentinel(argument)) {
+        sentinelProfile.enter();
+        throw TypesGen.asPanicSentinel(argument);
+      } else {
+        argumentValues[i] = argument;
+      }
     }
     return constructor.newInstance(argumentValues);
   }

engine/runtime/src/main/java/org/enso/interpreter/node/expression/builtin/io/PrintErrNode.java

@@ -1,13 +1,14 @@
 package org.enso.interpreter.node.expression.builtin.io;
 
 import com.oracle.truffle.api.CompilerDirectives;
-import com.oracle.truffle.api.CompilerDirectives.TruffleBoundary;
 import com.oracle.truffle.api.dsl.Cached;
 import com.oracle.truffle.api.dsl.CachedContext;
 import com.oracle.truffle.api.dsl.Specialization;
 import com.oracle.truffle.api.frame.VirtualFrame;
 import com.oracle.truffle.api.nodes.Node;
+import java.io.PrintStream;
 import org.enso.interpreter.Language;
+import org.enso.interpreter.dsl.AcceptsError;
 import org.enso.interpreter.dsl.BuiltinMethod;
 import org.enso.interpreter.dsl.MonadicState;
 import org.enso.interpreter.node.callable.InvokeCallableNode;
@@ -19,8 +20,6 @@
 import org.enso.interpreter.runtime.state.Stateful;
 import org.enso.interpreter.runtime.type.TypesGen;
 
-import java.io.PrintStream;
-
 @BuiltinMethod(
     type = "IO",
     name = "print_err",
@@ -31,7 +30,7 @@ static PrintErrNode build() {
   }
 
   abstract Stateful execute(
-      VirtualFrame frame, @MonadicState Object state, Object _this, Object message);
+      VirtualFrame frame, @MonadicState Object state, Object _this, @AcceptsError Object message);
 
   @Specialization
   Stateful doPrintText(

engine/runtime/src/main/java/org/enso/interpreter/node/expression/builtin/io/PrintlnNode.java

@@ -3,12 +3,12 @@
 import com.oracle.truffle.api.CompilerDirectives;
 import com.oracle.truffle.api.dsl.Cached;
 import com.oracle.truffle.api.dsl.CachedContext;
-import com.oracle.truffle.api.dsl.Fallback;
 import com.oracle.truffle.api.dsl.Specialization;
 import com.oracle.truffle.api.frame.VirtualFrame;
 import com.oracle.truffle.api.nodes.Node;
 import java.io.PrintStream;
 import org.enso.interpreter.Language;
+import org.enso.interpreter.dsl.AcceptsError;
 import org.enso.interpreter.dsl.BuiltinMethod;
 import org.enso.interpreter.dsl.MonadicState;
 import org.enso.interpreter.node.callable.InvokeCallableNode;
@@ -29,13 +29,13 @@ public abstract class PrintlnNode extends Node {
           InvokeCallableNode.ArgumentsExecutionMode.PRE_EXECUTED);
 
   abstract Stateful execute(
-      VirtualFrame frame, @MonadicState Object state, Object _this, Object message);
+      VirtualFrame frame, @MonadicState Object state, Object _this, @AcceptsError Object message);
 
   @Specialization
   Stateful doPrintText(
       VirtualFrame frame,
       Object state,
-      Object self,
+      Object _this,
       Text message,
       @CachedContext(Language.class) Context ctx,
       @Cached("build()") ToJavaStringNode toJavaStringNode) {
@@ -47,7 +47,7 @@ Stateful doPrintText(
   Stateful doPrint(
       VirtualFrame frame,
       Object state,
-      Object self,
+      Object _this,
       Object message,
       @CachedContext(Language.class) Context ctx,
       @Cached("buildSymbol(ctx)") UnresolvedSymbol symbol,

engine/runtime/src/main/java/org/enso/interpreter/node/expression/builtin/meta/IsAtomConstructorNode.java

@@ -1,6 +1,7 @@
 package org.enso.interpreter.node.expression.builtin.meta;
 
 import com.oracle.truffle.api.nodes.Node;
+import org.enso.interpreter.dsl.AcceptsError;
 import org.enso.interpreter.dsl.BuiltinMethod;
 import org.enso.interpreter.runtime.type.TypesGen;
 
@@ -9,7 +10,7 @@
     name = "is_atom_constructor",
     description = "Checks if the argument is a constructor.")
 public class IsAtomConstructorNode extends Node {
-  boolean execute(Object _this, Object value) {
+  boolean execute(Object _this, @AcceptsError Object value) {
     return TypesGen.isAtomConstructor(value);
   }
 }

engine/runtime/src/main/java/org/enso/interpreter/node/expression/builtin/meta/IsAtomNode.java

@@ -1,12 +1,13 @@
 package org.enso.interpreter.node.expression.builtin.meta;
 
 import com.oracle.truffle.api.nodes.Node;
+import org.enso.interpreter.dsl.AcceptsError;
 import org.enso.interpreter.dsl.BuiltinMethod;
 import org.enso.interpreter.runtime.type.TypesGen;
 
 @BuiltinMethod(type = "Meta", name = "is_atom", description = "Checks if the argument is an atom")
 public class IsAtomNode extends Node {
-  boolean execute(Object _this, Object value) {
+  boolean execute(Object _this, @AcceptsError Object value) {
     return TypesGen.isAtom(value);
   }
 }

engine/runtime/src/main/java/org/enso/interpreter/node/expression/builtin/meta/IsErrorNode.java

@@ -1,6 +1,7 @@
 package org.enso.interpreter.node.expression.builtin.meta;
 
 import com.oracle.truffle.api.nodes.Node;
+import org.enso.interpreter.dsl.AcceptsError;
 import org.enso.interpreter.dsl.BuiltinMethod;
 import org.enso.interpreter.runtime.type.TypesGen;
 
@@ -9,7 +10,7 @@
     name = "is_error",
     description = "Checks if the argument is an error.")
 public class IsErrorNode extends Node {
-  boolean execute(Object _this, Object value) {
+  boolean execute(Object _this, @AcceptsError Object value) {
     return TypesGen.isDataflowError(value);
   }
 }