[GR-33155] Implement interop exception messages on RubyException

PullRequest: truffleruby/3497

Author: eregon

doc/contributor/interop_details.md

@@ -16,6 +16,8 @@
 - **a `Class`**
 - **a `Hash`**
 - **an `Array`**
+- **an `Exception`**
+- **an `Exception` with a cause**
 - **`proc {...}`**
 - **`lambda {...}`**
 - **a `Method`**
@@ -307,11 +309,11 @@ When interop message `getHashValuesIterator` is sent
 ## Members related messages (incomplete)
 
 When interop message `readMember` is sent
-- to any non-immediate `Object` like **`nil`**, **`:symbol`**, **a `String`**, **a `BigDecimal`**, **an `Object`**, **a frozen `Object`**, **a `StructWithValue`**, **a `Class`**, **a `Hash`**, **an `Array`**, **`proc {...}`**, **`lambda {...}`**, **a `Method`**, **a `Truffle::FFI::Pointer`**, **polyglot pointer**, **polyglot array** or **polyglot hash**
+- to any non-immediate `Object` like **`nil`**, **`:symbol`**, **a `String`**, **a `BigDecimal`**, **an `Object`**, **a frozen `Object`**, **a `StructWithValue`**, **a `Class`**, **a `Hash`**, **an `Array`**, **an `Exception`**, **an `Exception` with a cause**, **`proc {...}`**, **`lambda {...}`**, **a `Method`**, **a `Truffle::FFI::Pointer`**, **polyglot pointer**, **polyglot array** or **polyglot hash**
   it returns a method with the given name when the method is defined.
-- to any non-immediate `Object` like **`nil`**, **`:symbol`**, **a `String`**, **a `BigDecimal`**, **an `Object`**, **a frozen `Object`**, **a `StructWithValue`**, **a `Class`**, **a `Hash`**, **an `Array`**, **`proc {...}`**, **`lambda {...}`**, **a `Method`**, **a `Truffle::FFI::Pointer`**, **polyglot pointer**, **polyglot array** or **polyglot hash**
+- to any non-immediate `Object` like **`nil`**, **`:symbol`**, **a `String`**, **a `BigDecimal`**, **an `Object`**, **a frozen `Object`**, **a `StructWithValue`**, **a `Class`**, **a `Hash`**, **an `Array`**, **an `Exception`**, **an `Exception` with a cause**, **`proc {...}`**, **`lambda {...}`**, **a `Method`**, **a `Truffle::FFI::Pointer`**, **polyglot pointer**, **polyglot array** or **polyglot hash**
   it fails with `UnknownIdentifierException` when the method is not defined.
-- to any non-immediate `Object` like **a `String`**, **an `Object`**, **a `StructWithValue`**, **a `Class`**, **a `Hash`**, **an `Array`**, **`proc {...}`**, **`lambda {...}`**, **a `Method`**, **a `Truffle::FFI::Pointer`**, **polyglot pointer**, **polyglot array** or **polyglot hash**
+- to any non-immediate `Object` like **a `String`**, **an `Object`**, **a `StructWithValue`**, **a `Class`**, **a `Hash`**, **an `Array`**, **an `Exception`**, **an `Exception` with a cause**, **`proc {...}`**, **`lambda {...}`**, **a `Method`**, **a `Truffle::FFI::Pointer`**, **polyglot pointer**, **polyglot array** or **polyglot hash**
   it reads the given instance variable.
 - to **polyglot members**
   it reads the value stored with the given name.
@@ -321,7 +323,7 @@ When interop message `readMember` is sent
   it fails with `UnsupportedMessageError`.
 
 When interop message `writeMember` is sent
-- to any non-immediate non-frozen `Object` like **a `String`**, **an `Object`**, **a `StructWithValue`**, **a `Class`**, **a `Hash`**, **an `Array`**, **`proc {...}`**, **`lambda {...}`**, **a `Method`**, **a `Truffle::FFI::Pointer`**, **polyglot pointer**, **polyglot array** or **polyglot hash**
+- to any non-immediate non-frozen `Object` like **a `String`**, **an `Object`**, **a `StructWithValue`**, **a `Class`**, **a `Hash`**, **an `Array`**, **an `Exception`**, **an `Exception` with a cause**, **`proc {...}`**, **`lambda {...}`**, **a `Method`**, **a `Truffle::FFI::Pointer`**, **polyglot pointer**, **polyglot array** or **polyglot hash**
   it writes the given instance variable.
 - to **polyglot members**
   it writes the given value under the given name.
@@ -332,10 +334,64 @@ When interop message `writeMember` is sent
 - otherwise
   it fails with `UnsupportedMessageError`.
 
+## Exception related messages
+
+When interop message `isException` is sent
+- to **an `Exception`** or **an `Exception` with a cause**
+  it returns true.
+- otherwise
+  it returns false.
+
+When interop message `throwException` is sent
+- to **an `Exception`** or **an `Exception` with a cause**
+  it throws the exception.
+- otherwise
+  it fails with `UnsupportedMessageError`.
+
+When interop message `getExceptionType` is sent
+- to **an `Exception`** or **an `Exception` with a cause**
+  it returns the exception type.
+- otherwise
+  it fails with `UnsupportedMessageError`.
+
+When interop message `hasExceptionMessage` is sent
+- to **an `Exception`** or **an `Exception` with a cause**
+  it returns true.
+- otherwise
+  it returns false.
+
+When interop message `getExceptionMessage` is sent
+- to **an `Exception`** or **an `Exception` with a cause**
+  it returns the message of the exception.
+- otherwise
+  it fails with `UnsupportedMessageError`.
+
+When interop message `hasExceptionStackTrace` is sent
+- to **an `Exception`** or **an `Exception` with a cause**
+  it returns true.
+- otherwise
+  it returns false.
+
+When interop message `getExceptionStackTrace` is sent
+- to **an `Exception`** or **an `Exception` with a cause**
+  it returns the stacktrace of the exception.
+- otherwise
+  it fails with `UnsupportedMessageError`.
+
+When interop message `hasExceptionCause` is sent
+- to **an `Exception` with a cause**
+  it returns true.
+- otherwise
+  it returns false.
+
+When interop message `getExceptionCause` is sent
+- to **an `Exception` with a cause**
+  it returns the cause of the exception.
+- otherwise
+  it fails with `UnsupportedMessageError`.
+
 ## Number related messages (missing)
 
 ## Instantiation related messages (missing)
 
-## Exception related messages (missing)
-
 ## Time related messages (unimplemented)

spec/truffle/interop/matrix_spec.rb

@@ -1,3 +1,5 @@
+# truffleruby_primitives: true
+
 # Copyright (c) 2018, 2021 Oracle and/or its affiliates. All rights reserved. This
 # code is released under a tri EPL/GPL/LGPL license. You can use it,
 # redistribute it and/or modify it under the terms of the:
@@ -243,6 +245,33 @@ def spec_it(subject)
       module:        Subject.(name: AN_INSTANCE) { Module.new },
       hash:          Subject.(name: AN_INSTANCE, doc: true) { {} },
       array:         Subject.(name: AN_INSTANCE, doc: true) { [] },
+      # raise & rescue to give it a backtrace
+      exception: Subject.(name: "an `Exception`", doc: true) do
+        begin
+          raise "the exception message"
+        rescue => e
+          e
+        end
+      end,
+      exception_with_cause: Subject.(name: "an `Exception` with a cause", doc: true) do
+        begin
+          raise "the cause"
+        rescue
+          begin
+            raise "the exception message"
+          rescue => e
+            e
+          end
+        end
+      end,
+      # also test RaiseException since it is what other languages see when they catch an exception from Ruby
+      raise_exception: Subject.(name: AN_INSTANCE) do
+        begin
+          raise "the exception message"
+        rescue => e
+          Primitive.exception_get_raise_exception(e)
+        end
+      end,
 
       proc:          Subject.(proc { |v| v }, name: code("proc {...}"), doc: true),
       lambda:        Subject.(-> v { v }, name: code("lambda {...}"), doc: true),
@@ -286,6 +315,7 @@ def spec_it(subject)
   immediate_subjects     = [:false, :true, :zero, :small_integer, :zero_float, :small_float]
   non_immediate_subjects = SUBJECTS.keys - immediate_subjects
   frozen_subjects        = [:big_decimal, :nil, :symbol, :strange_symbol, :frozen_object]
+  exception_subjects     = [:exception, :exception_with_cause, :raise_exception]
 
   # not part of the standard matrix, not considered in last rest case
   EXTRA_SUBJECTS = {
@@ -298,7 +328,7 @@ def spec_it(subject)
   def predicate(name, is, *message_args, &setup)
     -> subject do
       setup.call subject if setup
-      Truffle::Interop.send(name, subject, *message_args).send(is ? :should : :should_not, be_true)
+      Truffle::Interop.send(name, subject, *message_args).should == is
     end
   end
 
@@ -580,7 +610,7 @@ def array_element_predicate(message, predicate, insert_on_true_case)
       Delimiter["Members related messages (incomplete)"],
       Message[:readMember,
               Test.new("returns a method with the given name when the method is defined", "any non-immediate `Object`",
-                       *non_immediate_subjects - [:polyglot_object]) do |subject|
+                       *non_immediate_subjects - [:polyglot_object, :raise_exception]) do |subject|
                 Truffle::Interop.read_member(subject, 'to_s').should == subject.method(:to_s)
               end,
               Test.new("fails with `UnknownIdentifierException` when the method is not defined", "any non-immediate `Object`",
@@ -626,9 +656,48 @@ def array_element_predicate(message, predicate, insert_on_true_case)
               end,
               unsupported_test { |subject| Truffle::Interop.write_member(subject, :something, 'val') }],
 
+      Delimiter["Exception related messages"],
+      Message[:isException,
+              Test.new("returns true", *exception_subjects, &predicate(:exception?, true)),
+              Test.new("returns false", &predicate(:exception?, false))],
+      Message[:throwException,
+              Test.new("throws the exception", *exception_subjects) do |subject|
+                -> { Truffle::Interop.throw_exception(subject) }.should raise_error { |e| e.should.equal?(subject) }
+              end,
+              unsupported_test { |subject| Truffle::Interop.throw_exception(subject) }],
+      Message[:getExceptionType,
+              Test.new("returns the exception type", *exception_subjects) do |subject|
+                Truffle::Interop.exception_type(subject).should == :RUNTIME_ERROR
+              end,
+              unsupported_test { |subject| Truffle::Interop.exception_type(subject) }],
+      Message[:hasExceptionMessage,
+              Test.new("returns true", *exception_subjects,  &predicate(:has_exception_message?, true)),
+              Test.new("returns false", &predicate(:has_exception_message?, false))],
+      Message[:getExceptionMessage,
+              Test.new("returns the message of the exception", *exception_subjects) do |subject|
+                Truffle::Interop.exception_message(subject).should == "the exception message"
+              end,
+              unsupported_test { |subject| Truffle::Interop.exception_message(subject) }],
+      Message[:hasExceptionStackTrace,
+              Test.new("returns true", *exception_subjects,  &predicate(:has_exception_stack_trace?, true)),
+              Test.new("returns false", &predicate(:has_exception_stack_trace?, false))],
+      Message[:getExceptionStackTrace,
+              Test.new("returns the stacktrace of the exception", *exception_subjects) do |subject|
+                stacktrace = Truffle::Interop.exception_stack_trace(subject)
+                Truffle::Interop.should.has_array_elements?(stacktrace)
+              end,
+              unsupported_test { |subject| Truffle::Interop.exception_stack_trace(subject) }],
+      Message[:hasExceptionCause,
+              Test.new("returns true", :exception_with_cause, &predicate(:has_exception_cause?, true)),
+              Test.new("returns false", &predicate(:has_exception_cause?, false))],
+      Message[:getExceptionCause,
+              Test.new("returns the cause of the exception", :exception_with_cause) do |subject|
+                Truffle::Interop.exception_cause(subject).should == subject.cause
+              end,
+              unsupported_test { |subject| Truffle::Interop.exception_cause(subject) }],
+
       Delimiter["Number related messages (missing)"],
       Delimiter["Instantiation related messages (missing)"],
-      Delimiter["Exception related messages (missing)"],
       Delimiter["Time related messages (unimplemented)"],
   ]
 

src/main/java/org/truffleruby/core/exception/ExceptionNodes.java

@@ -353,4 +353,19 @@ protected int limit() {
 
     }
 
+    @Primitive(name = "exception_get_raise_exception")
+    public abstract static class GetRaiseExceptionNode extends CoreMethodArrayArgumentsNode {
+
+        @Specialization
+        protected Object getRaiseException(RubyException exception) {
+            RaiseException raiseException = exception.backtrace.getRaiseException();
+            if (raiseException != null) {
+                return raiseException;
+            } else {
+                return nil;
+            }
+        }
+
+    }
+
 }

src/main/java/org/truffleruby/core/exception/ExceptionOperations.java

@@ -97,7 +97,7 @@ public static String getMessage(Throwable throwable) {
     }
 
     @TruffleBoundary
-    private static String messageFieldToString(RubyException exception) {
+    public static String messageFieldToString(RubyException exception) {
         Object message = exception.message;
         RubyStringLibrary strings = RubyStringLibrary.getUncached();
         if (message == null || message == Nil.INSTANCE) {
@@ -115,7 +115,7 @@ public static String messageToString(RubyException exception) {
         Object messageObject = null;
         try {
             messageObject = DispatchNode.getUncached().call(exception, "message");
-        } catch (Throwable e) {
+        } catch (RaiseException e) {
             // Fall back to the internal message field
         }
         if (messageObject != null && RubyStringLibrary.getUncached().isRubyString(messageObject)) {

src/main/java/org/truffleruby/core/exception/RubyException.java

@@ -11,14 +11,18 @@
 
 import java.util.Set;
 
+import com.oracle.truffle.api.TruffleStackTraceElement;
 import com.oracle.truffle.api.interop.ExceptionType;
 import com.oracle.truffle.api.interop.InteropLibrary;
+import com.oracle.truffle.api.interop.UnsupportedMessageException;
 import com.oracle.truffle.api.library.CachedLibrary;
 import com.oracle.truffle.api.library.ExportLibrary;
 import com.oracle.truffle.api.library.ExportMessage;
 import com.oracle.truffle.api.nodes.Node;
 import org.truffleruby.RubyContext;
+import org.truffleruby.RubyLanguage;
 import org.truffleruby.core.VMPrimitiveNodes.VMRaiseExceptionNode;
+import org.truffleruby.core.array.ArrayHelpers;
 import org.truffleruby.core.array.RubyArray;
 import org.truffleruby.core.klass.RubyClass;
 import org.truffleruby.core.proc.RubyProc;
@@ -33,6 +37,8 @@
 import com.oracle.truffle.api.CompilerDirectives.TruffleBoundary;
 import com.oracle.truffle.api.object.Shape;
 
+import static org.truffleruby.language.RubyBaseNode.nil;
+
 @ExportLibrary(InteropLibrary.class)
 public class RubyException extends RubyDynamicObject implements ObjectGraphNode {
 
@@ -96,6 +102,49 @@ public RuntimeException throwException(
     public ExceptionType getExceptionType() {
         return ExceptionType.RUNTIME_ERROR;
     }
+
+    @ExportMessage
+    public boolean hasExceptionCause() {
+        return this.cause != nil;
+    }
+
+    @ExportMessage
+    public Object getExceptionCause() throws UnsupportedMessageException {
+        if (!hasExceptionCause()) {
+            throw UnsupportedMessageException.create();
+        }
+        return this.cause;
+    }
+
+    @ExportMessage
+    public boolean hasExceptionMessage() {
+        return true;
+    }
+
+    @ExportMessage
+    public Object getExceptionMessage() {
+        return ExceptionOperations.messageToString(this);
+    }
+
+    @ExportMessage
+    public boolean hasExceptionStackTrace() {
+        return this.backtrace != null;
+    }
+
+    @TruffleBoundary
+    @ExportMessage
+    public Object getExceptionStackTrace() throws UnsupportedMessageException {
+        if (!hasExceptionStackTrace()) {
+            throw UnsupportedMessageException.create();
+        }
+
+        TruffleStackTraceElement[] stackTrace = this.backtrace.getStackTrace();
+        Object[] items = new Object[stackTrace.length];
+        for (int i = 0; i < items.length; i++) {
+            items[i] = stackTrace[i].getGuestObject();
+        }
+        return ArrayHelpers.createArray(RubyContext.get(null), RubyLanguage.get(null), items);
+    }
     // endregion
 
 }

src/main/java/org/truffleruby/language/control/RaiseException.java

@@ -15,11 +15,8 @@
 import org.truffleruby.RubyContext;
 import org.truffleruby.core.exception.ExceptionOperations;
 import org.truffleruby.core.exception.RubyException;
-import org.truffleruby.core.module.ModuleFields;
 import org.truffleruby.language.backtrace.Backtrace;
 
-import com.oracle.truffle.api.CompilerDirectives.TruffleBoundary;
-
 /** A ControlFlowException holding a Ruby exception. */
 @SuppressWarnings("serial")
 @ExportLibrary(value = InteropLibrary.class, delegateTo = "exception")
@@ -55,11 +52,8 @@ public RubyException getException() {
     }
 
     @Override
-    @TruffleBoundary
     public String getMessage() {
-        final ModuleFields exceptionClass = exception.getLogicalClass().fields;
-        final String message = ExceptionOperations.messageToString(exception);
-        return String.format("%s (%s)", message, exceptionClass.getName());
+        return ExceptionOperations.messageFieldToString(exception);
     }
 
 }