[GR-35549] ContextSharingTest#testThreadCheck fails in polyglot isolate.

Author: tzezula

truffle/src/com.oracle.truffle.api/src/com/oracle/truffle/api/impl/Accessor.java

@@ -630,6 +630,12 @@ public abstract <T, G> Iterator<T> mergeHostGuestFrames(Object instrumentEnv, St
 
         public abstract boolean isResourceLimitCancelExecution(Throwable cancelExecution);
 
+        public abstract boolean isPolyglotEngineException(Throwable throwable);
+
+        public abstract Throwable getPolyglotEngineExceptionCause(Throwable engineException);
+
+        public abstract RuntimeException createPolyglotEngineException(RuntimeException cause);
+
         public abstract int getExitExceptionExitCode(Throwable cancelExecution);
 
         public abstract SourceSection getCancelExecutionSourceLocation(Throwable cancelExecution);

truffle/src/com.oracle.truffle.polyglot/src/com/oracle/truffle/polyglot/EngineAccessor.java

@@ -1479,6 +1479,21 @@ public boolean isResourceLimitCancelExecution(Throwable cancelExecution) {
             return ((PolyglotEngineImpl.CancelExecution) cancelExecution).isResourceLimit();
         }
 
+        @Override
+        public boolean isPolyglotEngineException(Throwable throwable) {
+            return throwable instanceof PolyglotEngineException;
+        }
+
+        @Override
+        public RuntimeException getPolyglotEngineExceptionCause(Throwable polyglotEngineException) {
+            return ((PolyglotEngineException) polyglotEngineException).e;
+        }
+
+        @Override
+        public RuntimeException createPolyglotEngineException(RuntimeException cause) {
+            return new PolyglotEngineException(cause);
+        }
+
         @Override
         public int getExitExceptionExitCode(Throwable exitException) {
             return ((PolyglotContextImpl.ExitException) exitException).getExitCode();

truffle/src/com.oracle.truffle.polyglot/src/com/oracle/truffle/polyglot/OtherContextGuestObject.java

@@ -189,6 +189,11 @@ static <T extends Exception> RuntimeException migrateException(PolyglotContextIm
             } else {
                 throw new OtherContextException(receiverContext, e, valueContext);
             }
+        } else if (e instanceof PolyglotEngineException) {
+            // [GR-35549] Truffle isolate enters the guest context as result of
+            // delegateLibrary#send(). Exceptions thrown by enter are wrapped as
+            // PolyglotEngineException. We need to unwrap them and throw as host exception.
+            throw toHostException(receiverContext, e);
         } else {
             throw e;
         }