More cleanup for failures on missing commands.

[rhatdan]

Currently in podman if a user specifies a command that does not exist
the tool shows the help information. This patch changes it to show
information like:

$ ./bin/podman foobar
Error: unrecognized command 'podman foobar'
Try 'podman --help' for more information.
$ ./bin/podman volume foobar
Error: unrecognized command podman volume foobar
Try 'podman volume --help' for more information.
$ ./bin/podman container foobar
Error: unrecognized command podman container foobar
Try 'podman container --help' for more information.

Signed-off-by: Daniel J Walsh dwalsh@redhat.com

[rhatdan]

@baude @mheon @edsantiago @TomSweeneyRedHat @giuseppe @vrothberg PTAL

[rhatdan]

Closes:#2530

[edsantiago]

Okay... I have no idea why, but am throwing this out in case it's obvious to anyone: this change slightly breaks the Usage format:

before:
    $ podman system --help
    Usage:
        podman system [command]
after:
    Usage:
      podman system [flags]
      podman system [command]

This breaks all the scripts I've written that rely on '[command]' to indicate 'this is a podman command with further subcommands'. I can find a workaround, I'm sure, but first: does anyone understand why this is happening, and is there an easy fix for it? (my guess is that if {{.Runnable}} in common.go is now triggering, but what tdo I know).

Oh, and I think you missed pod.go. (Found by my recursion scripts)

[edsantiago]

Update: this edit to common.go resolves the double-usage-line issue without, I think, introducing any unexpected behavior (but I'm still checking):

--- a/cmd/podman/common.go
+++ b/cmd/podman/common.go
@@ -525,7 +525,7 @@ func scrubServer(server string) string {
 // This blocks the desplaying of the global options. The main podman
 // command should not use this.
 func UsageTemplate() string {
-       return `Usage:{{if .Runnable}}
+       return `Usage:{{if (and .Runnable (not .HasAvailableSubCommands))}}
   {{.UseLine}}{{end}}{{if .HasAvailableSubCommands}}
   {{.CommandPath}} [command]{{end}}{{if gt (len .Aliases) 0}}
 

[edsantiago]

This is really exciting. Thank you for finding a way to address this.

I hope you'll accept my refactored PR (and the warning comment therein)

[edsantiago]

@rhatdan I need to head out soon but just want to make sure you saw my refactoring PR? There's a lot of unnecessary duplication here, and also a serious index dereferencing bug (which can be fixed in only one place, if you agree with my PR approach)

[rhatdan]

Sure lets finish this up tomorrow, Hopefully your idea works.

[rhatdan]

/retest
bot, retest this please

[openshift-ci-robot]

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[edsantiago]

/lgtm

I'd still encourage you to consider a more descriptive name than commandRunE, but otherwise this is really great and very much appreciated. Thank you.