Merge pull request #72 from lukasjarosch/feat/undefined-variable-hand…

…ling

feat: ignore variables with targetValue `nil`

variable.go

@@ -81,6 +81,9 @@ func ReplaceVariables(data Data, classFiles []*Class, predefinedVariables map[st
  return false
  }
 
+ // variables can be ignored, they are stored here :)
+ ignoredVariables := []Variable{}
+
  // TODO: gosh, make this a standalone function already
  replaceVariable := func(variable Variable) error {
  var targetValue interface{}
@@ -150,6 +153,15 @@ func ReplaceVariables(data Data, classFiles []*Class, predefinedVariables map[st
  return variable.FullName() != sourceValue
  }
 
+ // At this point, the variable might still point to something unknown (targetValue == nil).
+ // This case might occur if one defines an inventory value which uses bash / environment variables, which
+ // look like skipper variables, but actually aren't.
+ // In this case, we ignore this variable.
+ if targetValue == nil {
+ ignoredVariables = append(ignoredVariables, variable)
+ return nil
+ }
+
  // if the variable is not 'inline', we are going to 'attach' whatever the variable points to
  // with the variable. This allows you to import a list from a different class for example.
  // class-file:
@@ -188,6 +200,17 @@ func ReplaceVariables(data Data, classFiles []*Class, predefinedVariables map[st
  return err
  }
 
+ // remove the ignored variables from the found variables
+ // otherwise we would end up in an endless loop.
+ for _, ignored := range ignoredVariables {
+ for i, variable := range variables {
+ if variable.Name == ignored.Name {
+ variables[i] = variables[len(variables)-1]
+ variables = variables[:len(variables)-1]
+ }
+ }
+ }
+
  if len(variables) == 0 {
  break
  }