AutoComplete fails with NPE if message bundle key for command name is used

[bobtiernay-okta]

If the following is used for a command:

@Command(name = "${project.cli.command}", ...)

AutoComplete will fail with:

java.lang.NullPointerException
	at picocli.AutoComplete.generateFunctionCallsToArrContains(AutoComplete.java:563)
	at picocli.AutoComplete.generateEntryPointFunction(AutoComplete.java:544)
	at picocli.AutoComplete.bash(AutoComplete.java:471)
	at picocli.AutoComplete.bash(AutoComplete.java:436)
	at picocli.AutoComplete$App.call(AutoComplete.java:186)
	at picocli.AutoComplete$App.call(AutoComplete.java:96)
	at picocli.CommandLine.executeUserObject(CommandLine.java:1953)
	at picocli.CommandLine.access$1300(CommandLine.java:145)
	at picocli.CommandLine$RunLast.executeUserObjectOfLastSubcommandWithSameParent(CommandLine.java:2352)
	at picocli.CommandLine$RunLast.handle(CommandLine.java:2346)
	at picocli.CommandLine$RunLast.handle(CommandLine.java:2311)
	at picocli.CommandLine$AbstractParseResultHandler.execute(CommandLine.java:2179)
	at picocli.CommandLine.execute(CommandLine.java:2078)
	at picocli.AutoComplete.main(AutoComplete.java:74)
Usage: picocli.AutoComplete [-fhVw] [-c=<factoryClass>] [-n=<commandName>]
                            [-o=<autoCompleteScript>] [@<filename>...]
                            <commandLineFQCN>
Generates a bash completion script for the specified command class.
      [@<filename>...]       One or more argument files containing options.
      <commandLineFQCN>      Fully qualified class name of the annotated
                               `@Command` class to generate a completion script
                               for.
  -c, --factory=<factoryClass>
                             Optionally specify the fully qualified class name
                               of the custom factory to use to instantiate the
                               command class. When omitted, the default picocli
                               factory is used.
  -n, --name=<commandName>   Optionally specify the name of the command to
                               create a completion script for. When omitted,
                               the annotated class `@Command(name = "...")`
                               attribute is used. If no `@Command(name = ...)`
                               attribute exists, '<CLASS-SIMPLE-NAME>' (in
                               lower-case) is used.
  -o, --completionScript=<autoCompleteScript>
                             Optionally specify the path of the completion
                               script file to generate. When omitted, a file
                               named '<commandName>_completion' is generated in
                               the current directory.
  -w, --writeCommandScript   Write a '<commandName>' sample command script to
                               the same directory as the completion script.
  -f, --force                Overwrite existing script files.
  -h, --help                 Show this help message and exit.
  -V, --version              Print version information and exit.

Exit Codes:
  0   Successful program execution
  1   Usage error: user input for the command was incorrect, e.g., the wrong
        number of arguments, a bad flag, a bad syntax in a parameter, etc.
  2   The specified command script exists (Specify `--force` to overwrite).
  3   The specified completion script exists (Specify `--force` to overwrite).
  4   An exception occurred while generating the completion script.

System Properties:
Set the following system properties to control the exit code of this program:

* `"picocli.autocomplete.systemExitOnSuccess"`
   call `System.exit(0)` when execution completes normally.
* `"picocli.autocomplete.systemExitOnError"`
   call `System.exit(ERROR_CODE)` when an error occurs.

If these system properties are not defined or have value "false", this program
completes without terminating the JVM.

Example
-------
  java -cp "myapp.jar;picocli-4.6.1.jar" \
              picocli.AutoComplete my.pkg.MyClass

Note that this happens even when specifying the -n parameter.

Thus it would be useful to consider adding message bundle support for this and other use cases.

[remkop]

I have added some tests to the AutoCompleteTest, but I have been unable to reproduce the NullPointerException...

Can you provide an example of how to reproduce this issue, or point out what I am missing?

[bobtiernay-okta]

Ah, I think the issue is that the bundle in question is being set in the CommandLine and not as you have done in the annotation:

commandLine.setResourceBundle(ResourceBundle.getBundle("messages"));

Thus it probably cannot be found. I'm wondering if there is a way around this. Maybe the ability to specify a bundle file on the command line?

[remkop]

Oh, I see.
Yes, if you invoke AutoComplete.main with the name of your command, then that line commandLine.setResourceBundle... does not get invoked so the command does not have a resource bundle.

What is the reason you don't specify the resource bundle in the annotation of the top-level class?

[bobtiernay-okta]

Mainly to keep things DRY, global and centralized and not have to repeat in all commands.

[remkop]

Understood.
May I suggest you specify the resource bundle in the annotation of the top-level command?
That should cover all subcommands.
Using the annotations is the cleanest way to pass this information to AutoComplete.

[bobtiernay-okta]

Yep. That should work for me. Thanks for the suggestion.

On a related note, what about use cases where command lines are created without annotations? Are these supported today?

[remkop]

Yes, but when using the programmatic API your are building up a CommandSpec object dynamically, so you cannot use the AutoComplete.main method: the AutoComplete.main method uses reflection to build up a CommandSpec object from the annotations of the specified class.

Instead, you would pass your dynamically created CommandSpec object (wrapped in a CommandLine object) to one of the static bash methods in AutoComplete.

[remkop]

@bobtiernay-okta I am closing this issue; please let me know if I missed something, I can always reopen it. :-)