Persistent*Run of rootCmd will be skipped if its sub-command has the same Persistent*Run

[hyorigo]

I spent some time with https://github.com/carolynvs/stingoftheviper , and I found the strange behavior ---

• If only the PersistentPreRunE of rootCmd is defined, it will always be triggered.
• If both the PersistentPreRunE of rootCmd and its sub-command, only the sub-command one will be triggered.

If I need the Persistent*Run of rootCmd and its sub-command both being triggered, what should I do? Or maybe the current behavior is a bug?

[marckhouzam]

What you can do is have the PersistentPreRunE of the sub-cmd call the PersistentPreRunE of its parent.

[hyorigo]

@marckhouzam Oh, thanks! I found this logic, so why did you authors make this decision?

cobra/command.go

Lines 863 to 873 in 9ed1d71

	for p := c; p != nil; p = p.Parent() {
	if p.PersistentPostRunE != nil {
	if err := p.PersistentPostRunE(c, argWoFlags); err != nil {
	return err
	}
	break
	} else if p.PersistentPostRun != nil {
	p.PersistentPostRun(c, argWoFlags)
	break
	}
	}

Btw, as per your answer, I tried this code snippet in the sub-cmd, and got stack overflow:

	PersistentPreRunE: func(cmd *cobra.Command, args []string) error {
		if parentPreE := cmd.Parent().PersistentPreRunE; parentPreE != nil {
			if err := parentPreE(cmd, args); err != nil {
				return err
			}
		}

		// blab ... blab ... blah
		return nil
	},

It works after I changed cmd.Parent() into rootCmd, but I just couldn't understand why this would cause infinite loop, even I debugged step by step.

[marckhouzam]

@marckhouzam Oh, thanks! I found this logic, so why did you authors make this decision?

I can't say for sure what the original intent was, but based on our current discussion, this approach seems to give the most flexibility. It allows to either override an ancestor's PersistentPreRun function by defining one in a subcmd, and it allows to extend ancestor's PersistentPreRun by calling them as you are now doing.

Btw, as per your answer, I tried this code snippet in the sub-cmd, and got stack overflow:

	PersistentPreRunE: func(cmd *cobra.Command, args []string) error {
		if parentPreE := cmd.Parent().PersistentPreRunE; parentPreE != nil {
			if err := parentPreE(cmd, args); err != nil {

I'm guessing the problem is that you pass cmd to parentPreE when you should be passing cmd.Parent().

[hyorigo]

@marckhouzam Thanks for your help! I think we can close this issue now.

[marckhouzam]

@hyorigo would you mind closing the issue yourself? I don't have permissions.

[hyorigo]

OK. Done.