Make required name attributes work

1 files changed, 491 insertions, 0 deletions

diff --git a/lib/chef/property.rb b/lib/chef/property.rb
new file mode 100644
index 0000000000..8d160d7539
--- /dev/null
+++ b/lib/chef/property.rb
@@ -0,0 +1,491 @@
+require 'chef/exceptions'
+require 'chef/delayed_evaluator'
+
+class Chef
+  #
+  # Type and validation information for a property on a resource.
+  #
+  # A property named "x" manipulates the "@x" instance variable on a
+  # resource.  The *presence* of the variable (`instance_variable_defined?(@x)`)
+  # tells whether the variable is defined; it may have any actual value,
+  # constrained only by validation.
+  #
+  # Properties may have validation, defaults, and coercion, and have full
+  # support for lazy values.
+  #
+  # @see Chef::Resource.property
+  # @see Chef::DelayedEvaluator
+  #
+  class Property
+    #
+    # Create a new property.
+    #
+    # @param options [Hash<Symbol,Object>] Property options, including
+    #   control options here, as well as validation options (see
+    #   Chef::Mixin::ParamsValidate#validate for a description of validation
+    #   options).
+    #   @option options [Symbol] :name The name of this property.
+    #   @option options [Class] :declared_in The class this property comes from.
+    #   @option options [Symbol] :instance_variable_name The instance variable
+    #     tied to this property. Must include a leading `@`. Defaults to `@<name>`.
+    #     `nil` means the property is opaque and not tied to a specific instance
+    #     variable.
+    #   @option options [Boolean] :desired_state `true` if this property is part of desired
+    #     state. Defaults to `true`.
+    #   @option options [Boolean] :identity `true` if this property is part of object
+    #     identity. Defaults to `false`.
+    #   @option options [Boolean] :name_property `true` if this
+    #     property defaults to the same value as `name`. Equivalent to
+    #     `default: lazy { name }`, except that #property_is_set? will
+    #     return `true` if the property is set *or* if `name` is set.
+    #   @option options [Object] :default The value this property
+    #     will return if the user does not set one. If this is `lazy`, it will
+    #     be run in the context of the instance (and able to access other
+    #     properties) and cached. If not, the value will be frozen with Object#freeze
+    #     to prevent users from modifying it in an instance.
+    #   @option options [Proc] :computed The value this property will return if
+    #     the user does not set one. If this is `lazy`, it will be run in the
+    #     context of the instance (and able to access other properties).
+    #   @option options [Proc] :coerce A proc which will be called to
+    #     transform the user input to canonical form. The value is passed in,
+    #     and the transformed value returned as output. Lazy values will *not*
+    #     be passed to this method until after they are evaluated. Called in the
+    #     context of the resource (meaning you can access other properties).
+    #   @option options [Boolean] :required `true` if this property
+    #     must be present; `false` otherwise. This is checked after the resource
+    #     is fully initialized.
+    #
+    def initialize(**options)
+      options.each { |k,v| options[k.to_sym] = v if k.is_a?(String) }
+      options[:name_property] = options.delete(:name_attribute) unless options.has_key?(:name_property)
+      @options = options
+
+      if options.has_key?(:default)
+        options[:default] = options[:default].freeze
+      end
+      options[:name] = options[:name].to_sym if options[:name]
+      options[:instance_variable_name] = options[:instance_variable_name].to_sym if options[:instance_variable_name]
+    end
+
+    #
+    # The name of this property.
+    #
+    # @return [String]
+    #
+    def name
+      options[:name]
+    end
+
+    #
+    # The class this property was defined in.
+    #
+    # @return [Class]
+    #
+    def declared_in
+      options[:declared_in]
+    end
+
+    #
+    # The instance variable associated with this property.
+    #
+    # Defaults to `@<name>`
+    #
+    # @return [Symbol]
+    #
+    def instance_variable_name
+      if options.has_key?(:instance_variable_name)
+        options[:instance_variable_name]
+      elsif name
+        :"@#{name}"
+      end
+    end
+
+    #
+    # The raw default value for this resource.
+    #
+    # Does not coerce or validate the default. Does not evaluate lazy values.
+    #
+    # Defaults to `lazy { name }` if name_property is true; otherwise defaults to
+    # `nil`
+    #
+    def default
+      return options[:default] if options.has_key?(:default)
+      return Chef::DelayedEvaluator.new { name } if name_property?
+      nil
+    end
+
+    #
+    # Whether this is part of the resource's natural identity or not.
+    #
+    # @return [Boolean]
+    #
+    def identity?
+      options[:identity]
+    end
+
+    #
+    # Whether this is part of desired state or not.
+    #
+    # Defaults to true.
+    #
+    # @return [Boolean]
+    #
+    def desired_state?
+      return true if !options.has_key?(:desired_state)
+      options[:desired_state]
+    end
+
+    #
+    # Whether this is name_property or not.
+    #
+    # @return [Boolean]
+    #
+    def name_property?
+      options[:name_property]
+    end
+
+    #
+    # Whether this property has a default value.
+    #
+    # @return [Boolean]
+    #
+    def has_default?
+      options.has_key?(:default) || name_property?
+    end
+
+    #
+    # Whether this property has a computed default value.
+    #
+    # @return [Boolean]
+    #
+    def has_computed?
+      options.has_key?(:computed)
+    end
+
+    #
+    # Whether this property is required or not.
+    #
+    # @return [Boolean]
+    #
+    def required?
+      options[:required]
+    end
+
+    #
+    # Validation options.  (See Chef::Mixin::ParamsValidate#validate.)
+    #
+    # @return [Hash<Symbol,Object>]
+    #
+    def validation_options
+      @validation_options ||= options.reject { |k,v|
+        [:declared_in,:name,:instance_variable_name,:desired_state,:identity,:default,:name_property,:coerce,:required].include?(k)
+      }
+    end
+
+    #
+    # Handle the property being called.
+    #
+    # The base implementation does the property get-or-set:
+    #
+    # ```ruby
+    # resource.myprop # get
+    # resource.myprop value # set
+    # ```
+    #
+    # If multiple values or a block are passed, they will be passed to coerce.
+    # If there is no coerce method and multiple values are passed, we will throw
+    # an error.
+    #
+    # @param resource [Chef::Resource] The resource to get the property from.
+    # @param value The value to set the property to. If not passed or set to
+    #   NOT_PASSED, this is treated as a get.
+    #
+    # @return The current value of the property. If it is a `set`, lazy values
+    #   will be returned without running, validating or coercing. If it is a
+    #   `get`, the non-lazy, coerced, validated value will always be returned.
+    #
+    def call(resource, value=NOT_PASSED)
+      # myprop with no args
+      if value == NOT_PASSED
+        return get(resource)
+      end
+
+      # myprop nil is sometimes a get (backcompat)
+      if value.nil? && !explicitly_accepts_nil?(resource)
+        # If you say "my_property nil" and the property explicitly accepts
+        # nil values, we consider this a get.
+        Chef::Log.deprecation("#{name} nil currently does not overwrite the value of #{name}. This will change in Chef 13, and the value will be set to nil instead. Please change your code to explicitly accept nil using \"property :#{name}, [MyType, nil]\", or stop setting this value to nil.")
+        return get(resource)
+      end
+
+      # Anything else (myprop value) is a set
+      set(resource, value)
+    end
+
+    #
+    # Get the property value from the resource, handling lazy values,
+    # defaults, and validation.
+    #
+    # - If the property's value is lazy, it is evaluated, coerced and validated.
+    # - If the property has no value, and is required, raises ValidationFailed.
+    # - If the property has no value, but has a lazy default, it is evaluated,
+    #   coerced and validated. If the evaluated value is frozen, the resulting
+    # - If the property has no value, but has a default, the default value
+    #   will be returned and frozen. If the default value is lazy, it will be
+    #   evaluated, coerced and validated, and the result stored in the property.
+    # - If the property has no value, but is name_property, `resource.name`
+    #   is retrieved, coerced, validated and stored in the property.
+    # - Otherwise, `nil` is returned.
+    #
+    # @param resource [Chef::Resource] The resource to get the property from.
+    #
+    # @return The value of the property.
+    #
+    # @raise Chef::Exceptions::ValidationFailed If the value is invalid for
+    #   this property, or if the value is required and not set.
+    #
+    def get(resource)
+      if is_set?(resource)
+        value = get_value(resource)
+        if value.is_a?(DelayedEvaluator)
+          value = exec_in_resource(resource, value)
+          value = coerce(resource, value)
+          validate(resource, value)
+        end
+        value
+
+      else
+        raise Chef::Exceptions::ValidationFailed, "#{name} is required" if required?
+
+        if has_default?
+          value = default
+          if value.is_a?(DelayedEvaluator)
+            value = exec_in_resource(resource, value)
+            value = coerce(resource, value)
+            # We don't validate defaults
+            set_value(resource, value)
+          else
+            value = coerce(resource, value)
+          end
+        end
+      end
+    end
+
+    #
+    # Set the value of this property in the given resource.
+    #
+    # Non-lazy values are coerced and validated before being set. Coercion
+    # and validation of lazy values is delayed until they are first retrieved.
+    #
+    # @param resource [Chef::Resource] The resource to set this property in.
+    # @param value The value to set.
+    #
+    # @return The value that was set, after coercion (if lazy, still returns
+    #   the lazy value)
+    #
+    # @raise Chef::Exceptions::ValidationFailed If the value is invalid for
+    #   this property.
+    #
+    def set(resource, value)
+      unless value.is_a?(DelayedEvaluator)
+        value = coerce(resource, value)
+        validate(resource, value)
+      end
+      set_value(resource, value)
+    end
+
+    #
+    # Find out whether this property has been set.
+    #
+    # This will be true if:
+    # - The user explicitly set the value
+    # - The property has a default, and the value was retrieved.
+    #
+    # From this point of view, it is worth looking at this as "what does the
+    # user think this value should be." In order words, if the user grabbed
+    # the value, even if it was a default, they probably based calculations on
+    # it. If they based calculations on it and the value changes, the rest of
+    # the world gets inconsistent.
+    #
+    # @param resource [Chef::Resource] The resource to get the property from.
+    #
+    # @return [Boolean]
+    #
+    def is_set?(resource)
+      value_is_set?(resource)
+    end
+
+    #
+    # Reset the value of this property so that is_set? will return false and the
+    # default will be returned in the future.
+    #
+    # @param resource [Chef::Resource] The resource to get the property from.
+    #
+    def reset(resource)
+      reset_value(resource)
+    end
+
+    #
+    # Coerce an input value into canonical form for the property.
+    #
+    # After coercion, the value is suitable for storage in the resource.
+    # You must validate values after coercion, however.
+    #
+    # Does no special handling for lazy values.
+    #
+    # @param resource [Chef::Resource] The resource we're coercing against
+    #   (to provide context for the coerce).
+    # @param value The value to coerce.
+    #
+    # @return The coerced value.
+    #
+    # @raise Chef::Exceptions::ValidationFailed If the value is invalid for
+    #   this property.
+    #
+    def coerce(resource, value)
+      if options.has_key?(:coerce)
+        value = exec_in_resource(resource, options[:coerce], value)
+      end
+      value
+    end
+
+    #
+    # Validate a value.
+    #
+    # Calls Chef::Mixin::ParamsValidate#validate with #validation_options as
+    # options.
+    #
+    # @param resource [Chef::Resource] The resource we're validating against
+    #   (to provide context for the validate).
+    # @param value The value to validate.
+    #
+    # @raise Chef::Exceptions::ValidationFailed If the value is invalid for
+    #   this property.
+    #
+    def validate(resource, value)
+      resource.validate({ name => value }, { name => validation_options })
+    end
+
+    #
+    # Specialize this Property by making a duplicate with some added or
+    # changed options.
+    #
+    # @param options [Hash<Symbol,Object>] List of options that would be passed
+    #   to #initialize.
+    #
+    # @return [Property] The new property type.
+    #
+    def specialize(**modified_options)
+      Property.new(**options, **modified_options)
+    end
+
+    protected
+
+    #
+    # Find out whether this type accepts nil explicitly.
+    #
+    # A type accepts nil explicitly if "is" allows nil, it validates as nil, *and* is not simply
+    # an empty type.
+    #
+    # These examples accept nil explicitly:
+    # ```ruby
+    # property :a, [ String, nil ]
+    # property :a, [ String, NilClass ]
+    # property :a, [ String, proc { |v| v.nil? } ]
+    # ```
+    #
+    # This does not (because the "is" doesn't exist or doesn't have nil):
+    #
+    # ```ruby
+    # property :x, String
+    # ```
+    #
+    # These do not, even though nil would validate fine (because they do not
+    # have "is"):
+    #
+    # ```ruby
+    # property :a
+    # property :a, equal_to: [ 1, 2, 3, nil ]
+    # property :a, kind_of: [ String, NilClass ]
+    # property :a, respond_to: [ ]
+    # property :a, callbacks: { "a" => proc { |v| v.nil? } }
+    # ```
+    #
+    # @param resource [Chef::Resource] The resource we're coercing against
+    #   (to provide context for the coerce).
+    #
+    # @return [Boolean] Whether this value explicitly accepts nil.
+    #
+    # @api private
+    def explicitly_accepts_nil?(resource)
+      options.has_key?(:is) && resource.send(:_pv_is, { name => nil }, name, options[:is], raise_error: false)
+    end
+
+    def get_value(resource)
+      if instance_variable_name
+        resource.send(:instance_variable_get, instance_variable_name)
+      else
+        resource.send(name)
+      end
+    end
+
+    def set_value(resource, value)
+      if instance_variable_name
+        resource.send(:instance_variable_set, instance_variable_name, value)
+      else
+        resource.send(name, value)
+      end
+    end
+
+    def value_is_set?(resource)
+      if instance_variable_name
+        resource.send(:instance_variable_defined?, instance_variable_name)
+      else
+        true
+      end
+    end
+
+    def reset_value(resource)
+      if instance_variable_name
+        if value_is_set?(resource)
+          resource.send(:remove_instance_variable, instance_variable_name)
+        end
+      else
+        raise ArgumentError, "Property #{name} has no instance variable defined and cannot be reset"
+      end
+    end
+
+    def exec_in_resource(resource, proc, *args)
+      if resource
+        if proc.arity > args.size
+          value = proc.call(resource, *args)
+        else
+          value = resource.instance_exec(*args, &proc)
+        end
+      else
+        value = proc.call
+      end
+
+      if value.is_a?(DelayedEvaluator)
+        value = coerce(resource, value)
+        validate(resource, value)
+      end
+      value
+    end
+
+    attr_reader :options
+
+    # Used by #set_or_return to avoid emitting a deprecation warning for
+    # "value nil"
+    # @api private
+    class NonDeprecatedNilGetter < Property
+      def call(resource, value=NOT_PASSED)
+        if value.nil? && !explicitly_accepts_nil?(resource)
+          get(resource)
+        else
+          super
+        end
+      end
+    end
+  end
+end