Class: Psych::Merge::NodeWrapper

Inherits:
Object
  • Object
show all
Defined in:
lib/psych/merge/node_wrapper.rb

Overview

Wraps Psych::Nodes with comment associations, line information, and signatures.
This provides a unified interface for working with YAML nodes during merging.

Examples:

Basic usage

ast = Psych.parse_stream(yaml)
wrapper = NodeWrapper.new(ast.children.first, lines: source.lines)
wrapper.signature # => [:document, ...]

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(node, lines:, leading_comments: [], inline_comment: nil, key: nil) ⇒ NodeWrapper

Returns a new instance of NodeWrapper.

Parameters:

  • node (Psych::Nodes::Node) —

    Psych node to wrap

  • lines (Array<String>) —

    Source lines for content extraction

  • leading_comments (Array<Hash>) (defaults to: []) —

    Comments before this node

  • inline_comment (Hash, nil) (defaults to: nil) —

    Inline comment on the node’s line

  • key (String, nil) (defaults to: nil) —

    Key name if this is a mapping value



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# File 'lib/psych/merge/node_wrapper.rb', line 39

def initialize(node, lines:, leading_comments: [], inline_comment: nil, key: nil)
  @node = node
  @lines = lines
  @leading_comments = leading_comments
  @inline_comment = inline_comment
  @key = key

  # Extract line information from the Psych node.
  #
  # IMPORTANT: Psych (libyaml) line number semantics:
  # - start_line: 0-based, inclusive (first line of the node's content)
  # - end_line: 0-based, EXCLUSIVE (points to the line AFTER the last content line)
  #
  # Example for a mapping value spanning lines 4-5 (1-based):
  #   Psych reports: start_line=3, end_line=5 (0-based)
  #   - start_line=3 means line 4 (1-based) - correct
  #   - end_line=5 means "up to but not including line 5 (0-based)",
  #     i.e., last included line is 4 (0-based) = line 5 (1-based)
  #
  # Conversion to 1-based inclusive range:
  # - @start_line = node.start_line + 1  (0-based inclusive → 1-based inclusive)
  # - @end_line = node.end_line          (0-based exclusive → 1-based inclusive, since exclusive-1+1=same)
  #
  # If Psych/libyaml ever changes end_line to be inclusive, this will need adjustment.
  # See regression test: "does not duplicate keys when destination adds a new nested mapping"
  @start_line = node.start_line + 1 if node.respond_to?(:start_line) && node.start_line
  @end_line = node.end_line if node.respond_to?(:end_line) && node.end_line

  # Handle edge case where end_line might be before start_line
  @end_line = @start_line if @start_line && @end_line && @end_line < @start_line
end

Instance Attribute Details

#end_line ⇒ Integer (readonly)

Returns End line (1-based).

Returns:

  • (Integer) —

    End line (1-based)



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# File 'lib/psych/merge/node_wrapper.rb', line 26

def end_line
  @end_line
end

#inline_comment ⇒ Hash? (readonly)

Returns Inline/trailing comment on the same line.

Returns:

  • (Hash, nil) —

    Inline/trailing comment on the same line



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# File 'lib/psych/merge/node_wrapper.rb', line 20

def inline_comment
  @inline_comment
end

#key ⇒ String? (readonly)

Returns Key name for mapping entries.

Returns:

  • (String, nil) —

    Key name for mapping entries



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# File 'lib/psych/merge/node_wrapper.rb', line 29

def key
  @key
end

#leading_comments ⇒ Array<Hash> (readonly)

Returns Leading comments associated with this node.

Returns:

  • (Array<Hash>) —

    Leading comments associated with this node



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# File 'lib/psych/merge/node_wrapper.rb', line 17

def leading_comments
  @leading_comments
end

#lines ⇒ Array<String> (readonly)

Returns Source lines.

Returns:

  • (Array<String>) —

    Source lines



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# File 'lib/psych/merge/node_wrapper.rb', line 32

def lines
  @lines
end

#node ⇒ Psych::Nodes::Node (readonly)

Returns The wrapped Psych node.

Returns:

  • (Psych::Nodes::Node) —

    The wrapped Psych node



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# File 'lib/psych/merge/node_wrapper.rb', line 14

def node
  @node
end

#start_line ⇒ Integer (readonly)

Returns Start line (1-based).

Returns:

  • (Integer) —

    Start line (1-based)



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# File 'lib/psych/merge/node_wrapper.rb', line 23

def start_line
  @start_line
end

Instance Method Details

#alias? ⇒ Boolean

Check if this wraps an alias node

Returns:

  • (Boolean) 


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# File 'lib/psych/merge/node_wrapper.rb', line 105

def alias?
  @node.is_a?(::Psych::Nodes::Alias)
end

#alias_anchor ⇒ String?

Get the aliased anchor name

Returns:

  • (String, nil) 


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# File 'lib/psych/merge/node_wrapper.rb', line 165

def alias_anchor
  @node.anchor if alias?
end

#anchor ⇒ String?

Get the anchor name if this node has one

Returns:

  • (String, nil) 


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# File 'lib/psych/merge/node_wrapper.rb', line 111

def anchor
  @node.anchor if @node.respond_to?(:anchor)
end

#children(comment_tracker: nil) ⇒ Array<NodeWrapper>

Get children wrapped as NodeWrappers

Parameters:

  • comment_tracker (CommentTracker) (defaults to: nil) —

    For associating comments with children

Returns:



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# File 'lib/psych/merge/node_wrapper.rb', line 118

def children(comment_tracker: nil)
  return [] unless @node.respond_to?(:children) && @node.children

  wrap_children(@node.children, comment_tracker)
end

#content ⇒ String

Get the content for this node from source lines

Returns:

  • (String) 


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# File 'lib/psych/merge/node_wrapper.rb', line 171

def content
  return "" unless @start_line && @end_line

  (@start_line..@end_line).map { |ln| @lines[ln - 1] }.join
end

#freeze_node? ⇒ Boolean

Check if this is a freeze node

Returns:

  • (Boolean) 


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# File 'lib/psych/merge/node_wrapper.rb', line 81

def freeze_node?
  false
end

#inspect ⇒ String

String representation for debugging

Returns:

  • (String) 


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# File 'lib/psych/merge/node_wrapper.rb', line 187

def inspect
  node_type = @node.class.name.split("::").last
  "#<#{self.class.name} type=#{node_type} lines=#{@start_line}..#{@end_line} key=#{@key.inspect}>"
end

#mapping? ⇒ Boolean

Check if this wraps a mapping node

Returns:

  • (Boolean) 


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# File 'lib/psych/merge/node_wrapper.rb', line 87

def mapping?
  @node.is_a?(::Psych::Nodes::Mapping)
end

#mapping_entries(comment_tracker: nil) ⇒ Array<Array(NodeWrapper, NodeWrapper)>

Get mapping entries as key-value pairs of NodeWrappers

Parameters:

  • comment_tracker (CommentTracker) (defaults to: nil) —

    For associating comments with children

Returns:



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# File 'lib/psych/merge/node_wrapper.rb', line 127

def mapping_entries(comment_tracker: nil)
  return [] unless mapping?

  entries = []
  children = @node.children
  i = 0
  while i < children.length
    key_node = children[i]
    value_node = children[i + 1]
    break unless key_node && value_node

    key_wrapper = wrap_node(key_node, comment_tracker)
    value_wrapper = wrap_node(value_node, comment_tracker, key: extract_key_name(key_node))

    entries << [key_wrapper, value_wrapper]
    i += 2
  end

  entries
end

#scalar? ⇒ Boolean

Check if this wraps a scalar node

Returns:

  • (Boolean) 


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# File 'lib/psych/merge/node_wrapper.rb', line 99

def scalar?
  @node.is_a?(::Psych::Nodes::Scalar)
end

#sequence? ⇒ Boolean

Check if this wraps a sequence node

Returns:

  • (Boolean) 


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# File 'lib/psych/merge/node_wrapper.rb', line 93

def sequence?
  @node.is_a?(::Psych::Nodes::Sequence)
end

#sequence_items(comment_tracker: nil) ⇒ Array<NodeWrapper>

Get sequence items as NodeWrappers

Parameters:

  • comment_tracker (CommentTracker) (defaults to: nil) —

    For associating comments with children

Returns:



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# File 'lib/psych/merge/node_wrapper.rb', line 151

def sequence_items(comment_tracker: nil)
  return [] unless sequence?

  @node.children.map { |child| wrap_node(child, comment_tracker) }
end

#signature ⇒ Array?

Generate a signature for this node for matching purposes.
Signatures are used to identify corresponding nodes between template and destination.

Returns:

  • (Array, nil) —

    Signature array or nil if not signaturable



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# File 'lib/psych/merge/node_wrapper.rb', line 75

def signature
  compute_signature(@node)
end

#to_s ⇒ String

String representation of the node value.
For scalars, returns the value.
For other nodes, returns inspect.

Returns:

  • (String) 


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# File 'lib/psych/merge/node_wrapper.rb', line 181

def to_s
  value || inspect
end

#value ⇒ String?

Get the scalar value

Returns:

  • (String, nil) 


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# File 'lib/psych/merge/node_wrapper.rb', line 159

def value
  @node.value if scalar?
end