Bring back stacktrace in SS 4

[ullenboom]

stacktrace commannd is missing:

Built-In Commands
	version: Show version info
	quit, exit: Exit the shell
	clear: Clear the terminal screen
	help: Display help about available commands
	history: Display or save the history of previously run commands
	script: Execute commands from a script file

[fmbenhassine]

This was an untracked change 23d42b4. My bad.. apologies for the confusion. It was actually documented (see the Debug Mode section), but not mentioned in the migration guide. I will fix that.

The main reason of this change is that the stacktrace command requires global mutable state to keep the stacktrace of the last command and there is no good place for this global state.

Similar to many popular CLI frameworks/tools, Spring Shell 4 introduce a debug mode, which when enabled, prints the stack trace of the last command right away instead of the user asking for it right after. So the idea is that you configure the shell in debug mode once (like for example running Maven with -X flag) and have the stack trace of every error, instead of having to type stacktrace every time an error occurs.

[fmbenhassine]

not mentioned in the migration guide. I will fix that.

Done: https://github.com/spring-projects/spring-shell/wiki/v4-migration-guide#removal-of-the-stacktrace-command

I am not sure you were aware of that change since it was not mentioned in the migration guide until now, but do you think you still need the stacktrace command with that new debug mode?

[ullenboom]

Thanks! This is a good addition. However, if I set spring.shell.debug.enabled=true, I still get the default output:

shell:>minimumFreeDiskSpace
Unable to run command minimumFreeDiskSpace: null

Test case:

@Component
public class FsCommands {

  @Command(description = "Display required free disk space")
  public long minimumFreeDiskSpace() {
    throw new UnsupportedOperationException();
  }
}

I checked SpringShellProperties (https://github.com/spring-projects/spring-shell/blob/v4.0.0/spring-shell-core-autoconfigure/src/main/java/org/springframework/shell/core/autoconfigure/SpringShellProperties.java) and there is no nested class Debug and thus no enabled property.

[fmbenhassine]

Thank you for your feedback. The fact that the cause of the message is not reported is a known issue: #1285 which I planned for 4.0.1.

However, the property spring.shell.debug.enabled was implemented only as a System property. The Spring Boot related configuration was missed. I will fix that in 4.0.1 as well.

When both these issues are fixed, do you think you still need the stacktrace command? I don't think so as explained previously, but I would be grateful if you share your opinion as well.