nullpointer

[andreas graeper]

hi. i see a video on youtube about cobra (cli)

in a package c

 c/c.go   // root-command

 c/s.go   // sub-command

--c.go-

 var c = &cobra.Command {}

--s.go--

 var s = &cobra.Command{

 }

 func init(){

  c.AddCommand( s, .. )

 }

go-build ok

but if i run the program it crashes and i am told that s poinzrt is nil or invalid. 

so i thought that func init() is package-initialiser and maybe s is not initialized, so i left declaration 

 var s * command.Cobra = nil // explicit set to nil   

in package-scope and moved initialization into init function 

func init () {

  s = & cobra.Command { .. }

  if s!=nil and c!=nil {

  c.AddCommand(s)

  } else { panic("nilpointer") }

 }

but in the end, not the s was invalid but the c.

if there is a package-directory c/ and a.go b.go c.go all in same 'package c' are they initialized in alphabetic order ? or if there is an init-function (i.e in b.go ) using a symbol from a.go, is then the init-function in a.go called before ? 

why initializing a pointer in package-scope is done before (success), but inside init-function in the order the source-files are handled (crash) ? 

thanks in advance, andi

[Def Ceb]

I'm afk and haven't run a test yet, but it's strange.

Consulting the spec at https://go.dev/ref/spec#Package_initialization

> The entire package is initialized by assigning initial values to all its package-level variables followed by calling all init functions in the order they appear in the source, possibly in multiple files, as presented to the compiler. 

Unless I'm reading this wrong, this would indicate that the variable c should have been initialized before the init function was called, and this should have worked fine.

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[Jason E. Aten]

You should post a reproducer if you want a real answer; a playground link or little repo.