`IllegalStateException: Terminal has been closed` when exiting Shell application from within the IDE

[mp911de]

When running a Spring Shell application through the IDE and stopping the programm through the process kill button, then in almost all cases, the exit signal causes an exception:

java.lang.IllegalStateException: Terminal has been closed
	at org.jline.terminal.impl.AbstractTerminal.checkClosed(AbstractTerminal.java:143)
	at org.jline.terminal.impl.DumbTerminal.setAttributes(DumbTerminal.java:206)
	at org.jline.reader.impl.LineReaderImpl.readLine(LineReaderImpl.java:810)
	at org.jline.reader.impl.LineReaderImpl.readLine(LineReaderImpl.java:535)
	at org.springframework.shell.jline.JLineInputProvider.readInput(JLineInputProvider.java:28)
	at org.springframework.shell.core.InteractiveShellRunner.doRun(InteractiveShellRunner.java:94)
	at org.springframework.shell.core.InteractiveShellRunner.run(InteractiveShellRunner.java:83)
	at org.springframework.data.release.cli.ShellConfiguration.lambda$springShellApplicationRunner$1(ShellConfiguration.java:148)
	at org.springframework.boot.SpringApplication.lambda$callRunner$0(SpringApplication.java:788)
	at org.springframework.util.function.ThrowingConsumer$1.acceptWithException(ThrowingConsumer.java:82)
	at org.springframework.util.function.ThrowingConsumer.accept(ThrowingConsumer.java:60)
	at org.springframework.util.function.ThrowingConsumer$1.accept(ThrowingConsumer.java:86)
	at org.springframework.boot.SpringApplication.callRunner(SpringApplication.java:800)
	at org.springframework.boot.SpringApplication.callRunner(SpringApplication.java:788)
	at org.springframework.boot.SpringApplication.lambda$callRunners$0(SpringApplication.java:776)
	at java.base/java.util.stream.ForEachOps$ForEachOp$OfRef.accept(ForEachOps.java:184)
	at java.base/java.util.stream.SortedOps$SizedRefSortingSink.end(SortedOps.java:357)
	at java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:557)
	at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:546)
	at java.base/java.util.stream.ForEachOps$ForEachOp.evaluateSequential(ForEachOps.java:151)
	at java.base/java.util.stream.ForEachOps$ForEachOp$OfRef.evaluateSequential(ForEachOps.java:174)
	at java.base/java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:265)
	at java.base/java.util.stream.ReferencePipeline.forEach(ReferencePipeline.java:611)
	at org.springframework.boot.SpringApplication.callRunners(SpringApplication.java:776)
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:328)
	at org.springframework.data.release.Application.main(Application.java:51)

The issue surfaces only sometimes and upon application exit, it seems not to cause any harm, however, it would be neat to suppress the exception logging for this particular case. There is also another instance from JLineShellRunner that we tried to handle in our config code.

Version: 4.0.3

Config:

@Configuration(proxyBeanMethods = false)
public class ShellConfiguration {

	@Bean
	static BeanPostProcessor shellPostProcessor() {
		return new BeanPostProcessor() {
			@Override
			public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {
				if (bean instanceof InteractiveShellRunner runner) {
					runner.setDebugMode(true);
				}

				return bean;
			}
		};
	}

	@Bean
	@Primary
	@ConditionalOnProperty(prefix = "spring.shell.interactive", name = "enabled", havingValue = "true",
			matchIfMissing = true)
	public ShellRunner myJlineShellRunner(JLineInputProvider inputProvider, AbstractTerminal terminal,
			CommandParser commandParser, CommandRegistry commandRegistry, Environment environment) {
		JLineShellRunner jLineShellRunner = new JLineShellRunner(inputProvider, commandParser, commandRegistry) {

			// reduce mount of exceptions on close.
			@Override
			public void flush() {
				try {
					super.flush();
				} catch (Exception e) {
					try {
						terminal.input();
					} catch (IllegalStateException ex) {
						if (ex.getMessage() != null && ex.getMessage().contains("closed")) {
							stop();
						}
					}
				}
			}
		};
		Boolean debugMode = environment.getProperty("spring.shell.debug.enabled", Boolean.class, false);
		jLineShellRunner.setDebugMode(debugMode);
		return jLineShellRunner;
	}

	@Bean
	@ConditionalOnProperty(prefix = "spring.shell.interactive", name = "enabled", havingValue = "true",
			matchIfMissing = true)
	ApplicationRunner springShellApplicationRunner(ObjectProvider<InfoProperties> infoProperties,
			Environment environment, ObjectProvider<ShellRunner> shellRunner) {

		ResourceBanner banner = new ReleaseCliBanner(infoProperties);
		return args -> {

			PrintStream out = System.out;
			banner.printBanner(environment, getClass(), out);
			out.flush();

			ShellRunner r = shellRunner.getObject();
			if (r != null) {
				r.run(args.getSourceArgs());
			}
		};
	}

}

[czpilar]

I can confirm this: when the terminal is closed externally, JLine throws IllegalStateException: Terminal has been closed not only from readLine() but also from writer()/flush() (on a DumbTerminal even writer() calls checkClosed()), so the interactive runner reported it as an error instead of exiting cleanly.

The fix is to treat a closed terminal as EOF in JLineInputProvider.readInput() (it now returns null) and have JLineShellRunner.print()/flush() silently ignore it, so the shell exits without the spurious exception. I've also added a test that reproduces the scenario.

Fixed in PR #1364