code: func (m *Meta) extendedFlagSet(n string) *flag.FlagSet {
  	f := m.defaultFlagSet(n)
  
  	f.BoolVar(&m.input, "input", true, "input")
  	f.Var((*FlagTargetSlice)(&m.targets), "target", "resource to target")
  
  	if m.variableArgs.items == nil {
  		m.variableArgs = newRawFlags("-var")
  	}
  	varValues := m.variableArgs.Alias("-var")
  	varFiles := m.variableArgs.Alias("-var-file")
  	f.Var(varValues, "var", "variables")
  	f.Var(varFiles, "var-file", "variable file")
  
  	// Experimental features
  	experiment.Flag(f)
  
  	// commands that bypass locking will supply their own flag on this var,
  	// but set the initial meta value to true as a failsafe.
  	m.stateLock = true
  
  	return f
  }
docs: // extendedFlagSet adds custom flags that are mostly used by commands
  // that are used to run an operation like plan or apply.