Enable auto-flushing of output to fix testfeed details mode

documentation/src/docs/asciidoc/release-notes/release-notes-5.12.0-M1.adoc

@@ -18,6 +18,8 @@ JUnit repository on GitHub.
 
 * Fix support for disabling ANSI colors on the console when the `NO_COLOR` environment
   variable is available.
+* Enable auto-flushing of output in the `ConsoleLauncher` to fix issues with buffering,
+  in particular when using the `--details=testfeed` option.
 
 [[release-notes-5.12.0-M1-junit-platform-deprecations-and-breaking-changes]]
 ==== Deprecations and Breaking Changes

gradle/plugins/common/src/main/kotlin/junitbuild/exec/RunConsoleLauncher.kt

@@ -6,7 +6,13 @@ import org.gradle.api.file.ConfigurableFileCollection
 import org.gradle.api.plugins.JavaPluginExtension
 import org.gradle.api.provider.ListProperty
 import org.gradle.api.provider.Property
-import org.gradle.api.tasks.*
+import org.gradle.api.tasks.CacheableTask
+import org.gradle.api.tasks.Classpath
+import org.gradle.api.tasks.Input
+import org.gradle.api.tasks.Internal
+import org.gradle.api.tasks.Nested
+import org.gradle.api.tasks.SourceSetContainer
+import org.gradle.api.tasks.TaskAction
 import org.gradle.api.tasks.options.Option
 import org.gradle.jvm.toolchain.JavaLauncher
 import org.gradle.jvm.toolchain.JavaToolchainService
@@ -16,7 +22,6 @@ import org.gradle.process.CommandLineArgumentProvider
 import org.gradle.process.ExecOperations
 import trackOperationSystemAsInput
 import java.io.ByteArrayOutputStream
-import java.util.*
 import javax.inject.Inject
 
 @CacheableTask
@@ -97,4 +102,13 @@ abstract class RunConsoleLauncher @Inject constructor(private val execOperations
         debugging.set(enabled)
     }
 
+    @Suppress("unused")
+    @Option(
+        option = "show-output",
+        description = "Show output"
+    )
+    fun setShowOutput(showOutput: Boolean) {
+        hideOutput.set(!showOutput)
+    }
+
 }

junit-platform-console/src/main/java/org/junit/platform/console/ConsoleLauncher.java

@@ -30,36 +30,17 @@
 public class ConsoleLauncher {
 
 	public static void main(String... args) {
-		PrintWriter out = new PrintWriter(System.out);
-		PrintWriter err = new PrintWriter(System.err);
-		CommandResult<?> result = run(out, err, args);
+		CommandResult<?> result = newCommandFacade().run(args);
 		System.exit(result.getExitCode());
 	}
 
 	@API(status = INTERNAL, since = "1.0")
 	public static CommandResult<?> run(PrintWriter out, PrintWriter err, String... args) {
-		ConsoleLauncher consoleLauncher = new ConsoleLauncher(ConsoleTestExecutor::new, out, err);
-		return consoleLauncher.run(args);
+		return newCommandFacade().run(args, out, err);
 	}
 
-	private final ConsoleTestExecutor.Factory consoleTestExecutorFactory;
-	private final PrintWriter out;
-	private final PrintWriter err;
-
-	ConsoleLauncher(ConsoleTestExecutor.Factory consoleTestExecutorFactory, PrintWriter out, PrintWriter err) {
-		this.consoleTestExecutorFactory = consoleTestExecutorFactory;
-		this.out = out;
-		this.err = err;
-	}
-
-	CommandResult<?> run(String... args) {
-		try {
-			return new CommandFacade(consoleTestExecutorFactory).run(out, err, args);
-		}
-		finally {
-			out.flush();
-			err.flush();
-		}
+	private static CommandFacade newCommandFacade() {
+		return new CommandFacade(ConsoleTestExecutor::new);
 	}
 
 }

junit-platform-console/src/main/java/org/junit/platform/console/options/CommandFacade.java

@@ -33,10 +33,24 @@ public CommandFacade(ConsoleTestExecutor.Factory consoleTestExecutorFactory) {
 		this.consoleTestExecutorFactory = consoleTestExecutorFactory;
 	}
 
-	public CommandResult<?> run(PrintWriter out, PrintWriter err, String[] args) {
+	public CommandResult<?> run(String[] args) {
+		return run(args, Optional.empty());
+	}
+
+	public CommandResult<?> run(String[] args, PrintWriter out, PrintWriter err) {
+		try {
+			return run(args, Optional.of(new OutputStreamConfig(out, err)));
+		}
+		finally {
+			out.flush();
+			err.flush();
+		}
+	}
+
+	private CommandResult<?> run(String[] args, Optional<OutputStreamConfig> outputStreamConfig) {
 		Optional<String> version = ManifestVersionProvider.getImplementationVersion();
 		System.setProperty("junit.docs.version",
 			version.map(it -> it.endsWith("-SNAPSHOT") ? "snapshot" : it).orElse("current"));
-		return new MainCommand(consoleTestExecutorFactory).run(out, err, args);
+		return new MainCommand(consoleTestExecutorFactory).run(args, outputStreamConfig);
 	}
 }

junit-platform-console/src/main/java/org/junit/platform/console/options/MainCommand.java

@@ -103,10 +103,11 @@ private Object runCommand(String subcommand, Optional<String> triggeringOption)
 
 		List<String> args = new ArrayList<>(commandLine.getParseResult().expandedArgs());
 		triggeringOption.ifPresent(args::remove);
-		CommandResult<?> result = runCommand(commandLine.getOut(), //
-			commandLine.getErr(), //
+		CommandResult<?> result = runCommand( //
+			new CommandLine(command), //
 			args.toArray(new String[0]), //
-			command);
+			Optional.of(new OutputStreamConfig(commandLine)) //
+		);
 		this.commandResult = result;
 
 		printDeprecationWarning(subcommand, triggeringOption, commandLine);
@@ -130,24 +131,19 @@ private static void printDeprecationWarning(String subcommand, Optional<String>
 		err.flush();
 	}
 
-	CommandResult<?> run(PrintWriter out, PrintWriter err, String[] args) {
+	CommandResult<?> run(String[] args, Optional<OutputStreamConfig> outputStreamConfig) {
 		CommandLine commandLine = new CommandLine(this) //
 				.addSubcommand(new DiscoverTestsCommand(consoleTestExecutorFactory)) //
 				.addSubcommand(new ExecuteTestsCommand(consoleTestExecutorFactory)) //
 				.addSubcommand(new ListTestEnginesCommand());
-		return runCommand(out, err, args, commandLine);
+		return runCommand(commandLine, args, outputStreamConfig);
 	}
 
-	private static CommandResult<?> runCommand(PrintWriter out, PrintWriter err, String[] args, Object command) {
-		return runCommand(out, err, args, new CommandLine(command));
-	}
-
-	private static CommandResult<Object> runCommand(PrintWriter out, PrintWriter err, String[] args,
-			CommandLine commandLine) {
-		int exitCode = BaseCommand.initialize(commandLine) //
-				.setOut(out) //
-				.setErr(err) //
-				.execute(args);
+	private static CommandResult<?> runCommand(CommandLine commandLine, String[] args,
+			Optional<OutputStreamConfig> outputStreamConfig) {
+		BaseCommand.initialize(commandLine);
+		outputStreamConfig.ifPresent(it -> it.applyTo(commandLine));
+		int exitCode = commandLine.execute(args);
 		return CommandResult.create(exitCode, getLikelyExecutedCommand(commandLine).getExecutionResult());
 	}
 

junit-platform-console/src/main/java/org/junit/platform/console/options/OutputStreamConfig.java

@@ -0,0 +1,34 @@
+/*
+ * Copyright 2015-2024 the original author or authors.
+ *
+ * All rights reserved. This program and the accompanying materials are
+ * made available under the terms of the Eclipse Public License v2.0 which
+ * accompanies this distribution and is available at
+ *
+ * https://www.eclipse.org/legal/epl-v20.html
+ */
+
+package org.junit.platform.console.options;
+
+import java.io.PrintWriter;
+
+import picocli.CommandLine;
+
+class OutputStreamConfig {
+
+	private final PrintWriter out;
+	private final PrintWriter err;
+
+	OutputStreamConfig(CommandLine commandLine) {
+		this(commandLine.getOut(), commandLine.getErr());
+	}
+
+	OutputStreamConfig(PrintWriter out, PrintWriter err) {
+		this.out = out;
+		this.err = err;
+	}
+
+	void applyTo(CommandLine commandLine) {
+		commandLine.setOut(out).setErr(err);
+	}
+}

platform-tests/src/test/java/org/junit/platform/console/ConsoleLauncherTests.java

@@ -22,7 +22,6 @@
 import org.junit.jupiter.params.provider.Arguments;
 import org.junit.jupiter.params.provider.EmptySource;
 import org.junit.jupiter.params.provider.MethodSource;
-import org.junit.platform.console.tasks.ConsoleTestExecutor;
 
 /**
  * @since 1.0
@@ -36,8 +35,7 @@ class ConsoleLauncherTests {
 	@EmptySource
 	@MethodSource("commandsWithEmptyOptionExitCodes")
 	void displayHelp(String command) {
-		var consoleLauncher = new ConsoleLauncher(ConsoleTestExecutor::new, printSink, printSink);
-		var exitCode = consoleLauncher.run(command, "--help").getExitCode();
+		var exitCode = ConsoleLauncher.run(printSink, printSink, command, "--help").getExitCode();
 
 		assertEquals(0, exitCode);
 		assertThat(output()).contains("--help");
@@ -47,8 +45,7 @@ void displayHelp(String command) {
 	@EmptySource
 	@MethodSource("commandsWithEmptyOptionExitCodes")
 	void displayVersion(String command) {
-		var consoleLauncher = new ConsoleLauncher(ConsoleTestExecutor::new, printSink, printSink);
-		var exitCode = consoleLauncher.run(command, "--version").getExitCode();
+		var exitCode = ConsoleLauncher.run(printSink, printSink, command, "--version").getExitCode();
 
 		assertEquals(0, exitCode);
 		assertThat(output()).contains("JUnit Platform Console Launcher");
@@ -57,17 +54,15 @@ void displayVersion(String command) {
 	@ParameterizedTest(name = "{0}")
 	@MethodSource("commandsWithEmptyOptionExitCodes")
 	void displayBanner(String command) {
-		var consoleLauncher = new ConsoleLauncher(ConsoleTestExecutor::new, printSink, printSink);
-		consoleLauncher.run(command);
+		ConsoleLauncher.run(printSink, printSink, command);
 
 		assertThat(output()).contains("Thanks for using JUnit!");
 	}
 
 	@ParameterizedTest(name = "{0}")
 	@MethodSource("commandsWithEmptyOptionExitCodes")
 	void disableBanner(String command, int expectedExitCode) {
-		var consoleLauncher = new ConsoleLauncher(ConsoleTestExecutor::new, printSink, printSink);
-		var exitCode = consoleLauncher.run(command, "--disable-banner").getExitCode();
+		var exitCode = ConsoleLauncher.run(printSink, printSink, command, "--disable-banner").getExitCode();
 
 		assertEquals(expectedExitCode, exitCode);
 		assertThat(output()).doesNotContain("Thanks for using JUnit!");
@@ -76,8 +71,7 @@ void disableBanner(String command, int expectedExitCode) {
 	@ParameterizedTest(name = "{0}")
 	@MethodSource("commandsWithEmptyOptionExitCodes")
 	void executeWithUnknownCommandLineOption(String command) {
-		var consoleLauncher = new ConsoleLauncher(ConsoleTestExecutor::new, printSink, printSink);
-		var exitCode = consoleLauncher.run(command, "--all").getExitCode();
+		var exitCode = ConsoleLauncher.run(printSink, printSink, command, "--all").getExitCode();
 
 		assertEquals(-1, exitCode);
 		assertThat(output()).contains("Unknown option: '--all'").contains("Usage:");
@@ -90,8 +84,7 @@ private String output() {
 	@ParameterizedTest(name = "{0}")
 	@MethodSource("commandsWithEmptyOptionExitCodes")
 	void executeWithoutCommandLineOptions(String command, int expectedExitCode) {
-		var consoleLauncher = new ConsoleLauncher(ConsoleTestExecutor::new, printSink, printSink);
-		var actualExitCode = consoleLauncher.run(command).getExitCode();
+		var actualExitCode = ConsoleLauncher.run(printSink, printSink, command).getExitCode();
 
 		assertEquals(expectedExitCode, actualExitCode);
 	}

platform-tests/src/test/java/org/junit/platform/console/ConsoleLauncherWrapper.java

@@ -17,6 +17,7 @@
 import java.io.StringWriter;
 import java.util.Optional;
 
+import org.junit.platform.console.options.CommandFacade;
 import org.junit.platform.console.tasks.ConsoleTestExecutor;
 
 /**
@@ -26,16 +27,14 @@ class ConsoleLauncherWrapper {
 
 	private final StringWriter out = new StringWriter();
 	private final StringWriter err = new StringWriter();
-	private final ConsoleLauncher consoleLauncher;
+	private final ConsoleTestExecutor.Factory consoleTestExecutorFactory;
 
 	ConsoleLauncherWrapper() {
 		this(ConsoleTestExecutor::new);
 	}
 
 	private ConsoleLauncherWrapper(ConsoleTestExecutor.Factory consoleTestExecutorFactory) {
-		var outWriter = new PrintWriter(out, false);
-		var errWriter = new PrintWriter(err, false);
-		this.consoleLauncher = new ConsoleLauncher(consoleTestExecutorFactory, outWriter, errWriter);
+		this.consoleTestExecutorFactory = consoleTestExecutorFactory;
 	}
 
 	public ConsoleLauncherWrapperResult execute(String... args) {
@@ -47,7 +46,9 @@ public ConsoleLauncherWrapperResult execute(int expectedExitCode, String... args
 	}
 
 	public ConsoleLauncherWrapperResult execute(Optional<Integer> expectedCode, String... args) {
-		var result = consoleLauncher.run(args);
+		var outWriter = new PrintWriter(out, false);
+		var errWriter = new PrintWriter(err, false);
+		var result = new CommandFacade(consoleTestExecutorFactory).run(args, outWriter, errWriter);
 		var code = result.getExitCode();
 		var outText = out.toString();
 		var errText = err.toString();