Fix GatewayException.printStackTrace(PrintStream) (#763)

The printStackTrace() implementation taking a PrintStream (rather than a
PrintWriter) in the Java GatewayException class failed to print output.
This was due to the PrinterWriter used to wrap the supplied PrintStream
not being flushed.

This change calls the PrintStream overload with unit tests, instead of
the PrintWriter overload (to which it defers) to ensure both variants
behave correctly. The printStackTrace() implementation is updated to
correctly flush the PrintWriter used internally to wrap the supplied
PrintStream.

Signed-off-by: Mark S. Lewis <[email protected]>

java/src/main/java/org/hyperledger/fabric/client/GatewayException.java

@@ -63,7 +63,9 @@ public void printStackTrace() {
      */
     @Override
     public void printStackTrace(final PrintStream out) {
-        printStackTrace(new PrintWriter(out));
+        PrintWriter writer = new PrintWriter(out);
+        printStackTrace(writer);
+        writer.flush();
     }
 
     /**
@@ -76,7 +78,6 @@ public void printStackTrace(final PrintWriter out) {
 
         try (PrintWriter printer = new PrintWriter(message)) {
             super.printStackTrace(printer);
-            printer.flush();
         }
 
         List<ErrorDetail> details = getDetails();

java/src/test/java/org/hyperledger/fabric/client/GatewayExceptionTest.java

@@ -12,9 +12,10 @@
 import com.google.rpc.Code;
 import io.grpc.StatusRuntimeException;
 import io.grpc.protobuf.StatusProto;
-import java.io.CharArrayWriter;
-import java.io.PrintWriter;
+import java.io.ByteArrayOutputStream;
+import java.io.PrintStream;
 import java.util.Arrays;
+import java.util.Collections;
 import java.util.List;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
@@ -37,10 +38,9 @@ void error_details_are_printed() {
                         .build());
         GatewayException e = new GatewayException(newStatusRuntimeException(Code.ABORTED, "STATUS_MESSAGE", details));
 
-        CharArrayWriter actual = new CharArrayWriter();
-        try (PrintWriter out = new PrintWriter(actual)) {
+        ByteArrayOutputStream actual = new ByteArrayOutputStream();
+        try (PrintStream out = new PrintStream(actual)) {
             e.printStackTrace(out);
-            out.flush();
         }
 
         List<String> expected = details.stream()
@@ -49,6 +49,33 @@ void error_details_are_printed() {
         assertThat(actual.toString()).contains(expected);
     }
 
+    @Test
+    void message_from_StatusRuntimeException_is_printed() {
+        GatewayException e = new GatewayException(
+                newStatusRuntimeException(Code.ABORTED, "STATUS_MESSAGE", Collections.emptyList()));
+
+        ByteArrayOutputStream actual = new ByteArrayOutputStream();
+        try (PrintStream out = new PrintStream(actual)) {
+            e.printStackTrace(out);
+        }
+
+        String expected = e.getCause().getLocalizedMessage();
+        assertThat(actual.toString()).contains(expected);
+    }
+
+    @Test
+    void print_stream_passed_to_printStackTrace_not_closed() {
+        GatewayException e = new GatewayException(newStatusRuntimeException(Code.ABORTED, "", Collections.emptyList()));
+
+        ByteArrayOutputStream actual = new ByteArrayOutputStream();
+        try (PrintStream out = new PrintStream(actual)) {
+            e.printStackTrace(out);
+            out.println("EXPECTED_SUBSEQUENT_MESSAGE");
+        }
+
+        assertThat(actual.toString()).contains("EXPECTED_SUBSEQUENT_MESSAGE");
+    }
+
     private StatusRuntimeException newStatusRuntimeException(Code code, String message, List<ErrorDetail> details) {
         List<Any> anyDetails = details.stream().map(Any::pack).collect(Collectors.toList());
         com.google.rpc.Status status = com.google.rpc.Status.newBuilder()