Better errors with non-interactive mode

- Change how errors are printed for interactive
  vs non-interactive mode.
- This now changes behaviour so that stacktrace is printed
  if non-interactive mode is active so that user has a change
  to see the full error.
- Fixes #427

Author: jvalkeal

spring-shell-core/src/main/java/org/springframework/shell/result/ResultHandlerConfig.java

@@ -23,6 +23,7 @@
 import org.springframework.context.annotation.Configuration;
 import org.springframework.shell.TerminalSizeAware;
 import org.springframework.shell.command.CommandCatalog;
+import org.springframework.shell.context.ShellContext;
 import org.springframework.shell.jline.InteractiveShellRunner;
 
 /**
@@ -62,7 +63,7 @@ public CommandParserExceptionsExceptionResultHandler commandParserExceptionsExce
 
 	@Bean
 	public ThrowableResultHandler throwableResultHandler(Terminal terminal, CommandCatalog commandCatalog,
-		ObjectProvider<InteractiveShellRunner> interactiveApplicationRunner) {
-		return new ThrowableResultHandler(terminal, commandCatalog, interactiveApplicationRunner);
+			ShellContext shellContext, ObjectProvider<InteractiveShellRunner> interactiveApplicationRunner) {
+		return new ThrowableResultHandler(terminal, commandCatalog, shellContext, interactiveApplicationRunner);
 	}
 }

spring-shell-core/src/main/java/org/springframework/shell/result/ThrowableResultHandler.java

@@ -13,9 +13,11 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-
 package org.springframework.shell.result;
 
+import java.io.PrintWriter;
+import java.io.StringWriter;
+
 import org.jline.terminal.Terminal;
 import org.jline.utils.AttributedString;
 import org.jline.utils.AttributedStringBuilder;
@@ -24,15 +26,20 @@
 import org.springframework.beans.factory.ObjectProvider;
 import org.springframework.shell.ResultHandler;
 import org.springframework.shell.command.CommandCatalog;
+import org.springframework.shell.context.InteractionMode;
+import org.springframework.shell.context.ShellContext;
 import org.springframework.shell.jline.InteractiveShellRunner;
 import org.springframework.util.StringUtils;
 
 /**
  * A {@link ResultHandler} that prints thrown exceptions messages in red.
  *
- * <p>Also stores the last exception reported, so that details can be printed using a dedicated command.</p>
+ * Stores the last exception reported, so that details can be printed using a
+ * dedicated command if in interactive mode. Prints stacktrace if in
+ * non-interactive mode as dedicated command could not be used.
  *
  * @author Eric Bottard
+ * @author Janne Valkealahti
  */
 public class ThrowableResultHandler extends TerminalAwareResultHandler<Throwable> {
 
@@ -47,30 +54,46 @@ public class ThrowableResultHandler extends TerminalAwareResultHandler<Throwable
 
 	private ObjectProvider<InteractiveShellRunner> interactiveRunner;
 
-	public ThrowableResultHandler(Terminal terminal, CommandCatalog commandCatalog,
+	private ShellContext shellContext;
+
+	public ThrowableResultHandler(Terminal terminal, CommandCatalog commandCatalog, ShellContext shellContext,
 			ObjectProvider<InteractiveShellRunner> interactiveRunner) {
 		super(terminal);
 		this.commandCatalog = commandCatalog;
+		this.shellContext = shellContext;
 		this.interactiveRunner = interactiveRunner;
 	}
 
 	@Override
 	protected void doHandleResult(Throwable result) {
 		lastError = result;
-		String toPrint = StringUtils.hasLength(result.getMessage()) ? result.getMessage() : result.toString();
-		terminal.writer().println(new AttributedString(toPrint,
+		boolean shouldHandle = shouldHandle();
+
+		if (shouldHandle) {
+			String errorMsg = StringUtils.hasLength(result.getMessage()) ? result.getMessage() : result.toString();
+			terminal.writer().println(new AttributedString(errorMsg,
 				AttributedStyle.DEFAULT.foreground(AttributedStyle.RED)).toAnsi());
-		if (interactiveRunner.getIfAvailable() != null && commandCatalog.getRegistrations().keySet().contains(DETAILS_COMMAND_NAME)) {
-			terminal.writer().println(
-				new AttributedStringBuilder()
+
+			String noteMsg;
+			if (showShortError()) {
+				noteMsg = new AttributedStringBuilder()
 					.append("Details of the error have been omitted. You can use the ", AttributedStyle.DEFAULT.foreground(AttributedStyle.RED))
 					.append(DETAILS_COMMAND_NAME, AttributedStyle.DEFAULT.foreground(AttributedStyle.RED).bold())
 					.append(" command to print the full stacktrace.", AttributedStyle.DEFAULT.foreground(AttributedStyle.RED))
-					.toAnsi()
-			);
+					.toAnsi();
+			}
+			else {
+				StringWriter sw = new StringWriter();
+				PrintWriter pw = new PrintWriter(sw);
+				result.printStackTrace(pw);
+				String stacktraceStr = sw.toString();
+				noteMsg = new AttributedString(stacktraceStr,
+						AttributedStyle.DEFAULT.foreground(AttributedStyle.RED)).toAnsi();
+			}
+			terminal.writer().println(noteMsg);
+			terminal.writer().flush();
 		}
-		terminal.writer().flush();
-		if (interactiveRunner.getIfAvailable() == null) {
+		else {
 			if (result instanceof RuntimeException) {
 				throw (RuntimeException) result;
 			}
@@ -89,4 +112,13 @@ else if (result instanceof Error) {
 	public Throwable getLastError() {
 		return lastError;
 	}
+
+	private boolean shouldHandle() {
+		return interactiveRunner.getIfAvailable() != null;
+	}
+
+	private boolean showShortError() {
+		return commandCatalog.getRegistrations().keySet().contains(DETAILS_COMMAND_NAME)
+				&& this.shellContext.getInteractionMode() == InteractionMode.INTERACTIVE;
+	}
 }