comments.go

Documentation: sigs.k8s.io/kustomize/kyaml/comments

     1  // Copyright 2019 The Kubernetes Authors.
     2  // SPDX-License-Identifier: Apache-2.0
     3  
     4  package comments
     5  
     6  import (
     7  	"sigs.k8s.io/kustomize/kyaml/openapi"
     8  	"sigs.k8s.io/kustomize/kyaml/yaml"
     9  	"sigs.k8s.io/kustomize/kyaml/yaml/walk"
    10  )
    11  
    12  // CopyComments recursively copies the comments on fields in from to fields in to
    13  func CopyComments(from, to *yaml.RNode) error {
    14  	// from node should not be modified, it should be just used as a reference
    15  	fromCopy := from.Copy()
    16  	copyFieldComments(fromCopy, to)
    17  	// walk the fields copying comments
    18  	_, err := walk.Walker{
    19  		Sources:            []*yaml.RNode{fromCopy, to},
    20  		Visitor:            &copier{},
    21  		VisitKeysAsScalars: true}.Walk()
    22  	return err
    23  }
    24  
    25  // copier implements walk.Visitor, and copies comments to fields shared between 2 instances
    26  // of a resource
    27  type copier struct{}
    28  
    29  func (c *copier) VisitMap(s walk.Sources, _ *openapi.ResourceSchema) (*yaml.RNode, error) {
    30  	copyFieldComments(s.Dest(), s.Origin())
    31  	return s.Dest(), nil
    32  }
    33  
    34  func (c *copier) VisitScalar(s walk.Sources, _ *openapi.ResourceSchema) (*yaml.RNode, error) {
    35  	to := s.Origin()
    36  	// TODO: File a bug with upstream yaml to handle comments for FoldedStyle scalar nodes
    37  	// Hack: convert FoldedStyle scalar node to DoubleQuotedStyle as the line comments are
    38  	// being serialized without space
    39  	// https://github.com/GoogleContainerTools/kpt/issues/766
    40  	if to != nil && to.Document().Style == yaml.FoldedStyle {
    41  		to.Document().Style = yaml.DoubleQuotedStyle
    42  	}
    43  
    44  	copyFieldComments(s.Dest(), to)
    45  	return s.Dest(), nil
    46  }
    47  
    48  func (c *copier) VisitList(s walk.Sources, _ *openapi.ResourceSchema, _ walk.ListKind) (
    49  	*yaml.RNode, error) {
    50  	copyFieldComments(s.Dest(), s.Origin())
    51  	destItems := s.Dest().Content()
    52  	originItems := s.Origin().Content()
    53  
    54  	for i := 0; i < len(destItems) && i < len(originItems); i++ {
    55  		dest := destItems[i]
    56  		origin := originItems[i]
    57  
    58  		if dest.Value == origin.Value {
    59  			// We copy the comments recursively on each node in the list.
    60  			if err := CopyComments(yaml.NewRNode(dest), yaml.NewRNode(origin)); err != nil {
    61  				return nil, err
    62  			}
    63  		}
    64  	}
    65  
    66  	return s.Dest(), nil
    67  }
    68  
    69  // copyFieldComments copies the comment from one field to another
    70  func copyFieldComments(from, to *yaml.RNode) {
    71  	if from == nil || to == nil {
    72  		return
    73  	}
    74  	if to.Document().LineComment == "" {
    75  		to.Document().LineComment = from.Document().LineComment
    76  	}
    77  	if to.Document().HeadComment == "" {
    78  		to.Document().HeadComment = from.Document().HeadComment
    79  	}
    80  	if to.Document().FootComment == "" {
    81  		to.Document().FootComment = from.Document().FootComment
    82  	}
    83  }
    84
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