# class Gem::Resolver::Molinillo::VersionConflict

An error caused by conflicts in version

### Attributes

conflicts[R]

@return [{String => Resolution::Conflict}] the conflicts that caused

    resolution to fail

specification_provider[R]

@return [SpecificationProvider] the specification provider used during

    resolution

### Public Class Methods

new(conflicts, specification_provider) click to toggle source

Initializes a new error with the given version conflicts. @param [{String => Resolution::Conflict}] conflicts see {#conflicts} @param [SpecificationProvider] `specification_provider` see {#specification_provider}

Calls superclass method `Exception::new`

    # File lib/rubygems/resolver/molinillo/lib/molinillo/errors.rb, line 66
    def initialize(conflicts, specification_provider)
      pairs = []
      conflicts.values.flat_map(&:requirements).each do |conflicting|
        conflicting.each do |source, conflict_requirements|
          conflict_requirements.each do |c|
            pairs << [c, source]
          end
        end
      end

      super "Unable to satisfy the following requirements:\n\n" \
        "#{pairs.map { |r, d| "- `#{r}` required by `#{d}`" }.join("\n")}"

      @conflicts = conflicts
      @specification_provider = specification_provider
    end

### Public Instance Methods

message_with_trees(opts = {}) click to toggle source

@return [String] An error message that includes requirement trees,

    which is much more detailed & customizable than the default message

@param [Hash] opts the options to create a message with. @option opts [String] :solver_name The user-facing name of the solver @option opts [String] :possibility_type The generic name of a possibility @option opts [Proc] :reduce_trees A proc that reduced the list of requirement trees @option opts [Proc] :printable_requirement A proc that pretty-prints requirements @option opts [Proc] :additional_message_for_conflict A proc that appends additional

    messages for each conflict

@option opts [Proc] :version_for_spec A proc that returns the version number for a

    possibility

    # File lib/rubygems/resolver/molinillo/lib/molinillo/errors.rb, line 97
    def message_with_trees(opts = {})
      solver_name = opts.delete(:solver_name) { self.class.name.split('::').first }
      possibility_type = opts.delete(:possibility_type) { 'possibility named' }
      reduce_trees = opts.delete(:reduce_trees) { proc { |trees| trees.uniq.sort_by(&:to_s) } }
      printable_requirement = opts.delete(:printable_requirement) { proc { |req| req.to_s } }
      additional_message_for_conflict = opts.delete(:additional_message_for_conflict) { proc {} }
      version_for_spec = opts.delete(:version_for_spec) { proc(&:to_s) }
      incompatible_version_message_for_conflict = opts.delete(:incompatible_version_message_for_conflict) do
        proc do |name, _conflict|
          %(#{solver_name} could not find compatible versions for #{possibility_type} "#{name}":)
        end
      end

      conflicts.sort.reduce(''.dup) do |o, (name, conflict)|
        o << "\n" << incompatible_version_message_for_conflict.call(name, conflict) << "\n"
        if conflict.locked_requirement
          o << %(  In snapshot (#{name_for_locking_dependency_source}):\n)
          o << %(    #{printable_requirement.call(conflict.locked_requirement)}\n)
          o << %(\n)
        end
        o << %(  In #{name_for_explicit_dependency_source}:\n)
        trees = reduce_trees.call(conflict.requirement_trees)

        o << trees.map do |tree|
          t = ''.dup
          depth = 2
          tree.each do |req|
            t << '  ' * depth << printable_requirement.call(req)
            unless tree.last == req
              if spec = conflict.activated_by_name[name_for(req)]
                t << %( was resolved to #{version_for_spec.call(spec)}, which)
              end
              t << %( depends on)
            end
            t << %(\n)
            depth += 1
          end
          t
        end.join("\n")

        additional_message_for_conflict.call(o, name, conflict)

        o
      end.strip
    end