github.com/terramate-io/tf@v0.0.0-20230830114523-fce866b4dfcd/states/instance_generation.go (about)

     1  // Copyright (c) HashiCorp, Inc.
     2  // SPDX-License-Identifier: MPL-2.0
     3  
     4  package states
     5  
     6  // Generation is used to represent multiple objects in a succession of objects
     7  // represented by a single resource instance address. A resource instance can
     8  // have multiple generations over its lifetime due to object replacement
     9  // (when a change can't be applied without destroying and re-creating), and
    10  // multiple generations can exist at the same time when create_before_destroy
    11  // is used.
    12  //
    13  // A Generation value can either be the value of the variable "CurrentGen" or
    14  // a value of type DeposedKey. Generation values can be compared for equality
    15  // using "==" and used as map keys. The zero value of Generation (nil) is not
    16  // a valid generation and must not be used.
    17  type Generation interface {
    18  	generation()
    19  }
    20  
    21  // CurrentGen is the Generation representing the currently-active object for
    22  // a resource instance.
    23  var CurrentGen Generation