RFR: 1275: An unknown sub-command gives a confusing error message [v3]

[Guoxiong Li]

> Hi all,
> 
> When using the unknown command, the client will output the unexpected message. For example:
> 
> 
> $ git-pr lis 123
> 
> error: unexpected input: 123
> usage: git-pr [options] [<COMMAND>]
> 	-h, --help      Show help
> 	    --verbose   Turn on verbose output
> 	    --debug     Turn on debugging output
> 	    --version   Print the version of this tool
> 
> 
> When the client can't identify the sub-command `git-pr lis`, it will execute the default command `git-pr help` and will pass `lis 123` as the argument to the `git-pr help` command. And the `git-pr help` can resolve only one argument, which is `lis` in this example, so it would output `error: unexpected input: 123`.
> 
> This patch will output more information to the user:
> 
> 
> $ git-pr lis 123
> 
> Can't find the sub-command 'lis', the default sub-command 'help' will be executed.
> The arguments [lis, 123] will be passed to the default sub-command.
> 
> error: unexpected input: 123
> usage: git-pr [options] [<COMMAND>]
> 	-h, --help      Show help
> 	    --verbose   Turn on verbose output
> 	    --debug     Turn on debugging output
> 	    --version   Print the version of this tool
> 
> 
> The added information can let the user know why the following output is shown.
> 
> Thanks for taking the time to review.
> 
> Best Regards,
> -- Guoxiong

Guoxiong Li has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains three additional commits since the last revision:

 - Merge branch 'master' into SKARA-1275
 - Adjust the message. Excluded the 'git-webrev'.
 - 1275: The unknown sub-command will ouput the unexpected message

-------------

Changes:
  - all: https://git.openjdk.java.net/skara/pull/1257/files
  - new: https://git.openjdk.java.net/skara/pull/1257/files/6e40540d..e72b96dd

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=skara&pr=1257&range=02
 - incr: https://webrevs.openjdk.java.net/?repo=skara&pr=1257&range=01-02

  Stats: 35 lines in 13 files changed: 20 ins; 1 del; 14 mod
  Patch: https://git.openjdk.java.net/skara/pull/1257.diff
  Fetch: git fetch https://git.openjdk.java.net/skara pull/1257/head:pull/1257

PR: https://git.openjdk.java.net/skara/pull/1257