♻️ Define config defaults with the attr definitions

At the cost of one big conflict now, this should significantly reduce
future merge conflicts in the config file.  It's also easier to match
documentation with default values when they're right next to each other.

This also assigns all of the original (`Config[0]`) defaults explicitly,
and not only where they differ from Config.default.

Author: nevans

lib/net/imap/config.rb

@@ -212,15 +212,15 @@ def self.[](config)
       # See Net::IMAP.new and Net::IMAP#starttls.
       #
       # The default value is +30+ seconds.
-      attr_accessor :open_timeout, type: Integer
+      attr_accessor :open_timeout, type: Integer, default: 30
 
       # Seconds to wait until an IDLE response is received, after
       # the client asks to leave the IDLE state.
       #
       # See Net::IMAP#idle and Net::IMAP#idle_done.
       #
       # The default value is +5+ seconds.
-      attr_accessor :idle_response_timeout, type: Integer
+      attr_accessor :idle_response_timeout, type: Integer, default: 5
 
       # Whether to use the +SASL-IR+ extension when the server and \SASL
       # mechanism both support it.  Can be overridden by the +sasl_ir+ keyword
@@ -236,7 +236,10 @@ def self.[](config)
       #
       # [+true+ <em>(default since +v0.4+)</em>]
       #   Use +SASL-IR+ when it is supported by the server and the mechanism.
-      attr_accessor :sasl_ir, type: :boolean
+      attr_accessor :sasl_ir, type: :boolean, defaults: {
+        0.0r => false,
+        0.4r => true,
+      }
 
       # Controls the behavior of Net::IMAP#login when the +LOGINDISABLED+
       # capability is present.  When enforced, Net::IMAP will raise a
@@ -260,7 +263,10 @@ def self.[](config)
       #
       attr_accessor :enforce_logindisabled, type: Enum[
         false, :when_capabilities_cached, true
-      ]
+      ], defaults: {
+        0.0r => false,
+        0.5r => true,
+      }
 
       # The maximum allowed server response size.  When +nil+, there is no limit
       # on response size.
@@ -294,7 +300,10 @@ def self.[](config)
       #
       # * original: +nil+ <em>(no limit)</em>
       # * +0.5+: 512 MiB
-      attr_accessor :max_response_size, type: Integer?
+      attr_accessor :max_response_size, type: Integer?, defaults: {
+        0.0r => nil,
+        0.5r => 512 << 20, # 512 MiB
+      }
 
       # Controls the behavior of Net::IMAP#responses when called without any
       # arguments (+type+ or +block+).
@@ -324,7 +333,11 @@ def self.[](config)
       # Note: #responses_without_args is an alias for #responses_without_block.
       attr_accessor :responses_without_block, type: Enum[
         :silence_deprecation_warning, :warn, :frozen_dup, :raise,
-      ]
+      ], defaults: {
+        0.0r => :silence_deprecation_warning,
+        0.5r => :warn,
+        0.6r => :frozen_dup,
+      }
 
       alias responses_without_args  responses_without_block  # :nodoc:
       alias responses_without_args= responses_without_block= # :nodoc:
@@ -369,7 +382,11 @@ def self.[](config)
       #    ResponseParser _only_ uses AppendUIDData and CopyUIDData.
       attr_accessor :parser_use_deprecated_uidplus_data, type: Enum[
         true, :up_to_max_size, false
-      ]
+      ], defaults: {
+        0.0r => true,
+        0.5r => :up_to_max_size,
+        0.6r => false,
+      }
 
       # The maximum +uid-set+ size that ResponseParser will parse into
       # deprecated UIDPlusData.  This limit only applies when
@@ -393,7 +410,13 @@ def self.[](config)
       # * +0.5+: <tt>100</tt>
       # * +0.6+: <tt>0</tt>
       #
-      attr_accessor :parser_max_deprecated_uidplus_data_size, type: Integer
+      attr_accessor :parser_max_deprecated_uidplus_data_size, type: Integer,
+        defaults: {
+          0.0r => 10_000,
+          0.4r =>  1_000,
+          0.5r =>    100,
+          0.6r =>      0,
+        }
 
       # Creates a new config object and initialize its attribute with +attrs+.
       #
@@ -482,34 +505,6 @@ def defaults_hash
 
       @global = default.new
 
-      version_defaults[0r] = {
-        sasl_ir: false,
-        responses_without_block: :silence_deprecation_warning,
-        enforce_logindisabled: false,
-        max_response_size: nil,
-        parser_use_deprecated_uidplus_data: true,
-        parser_max_deprecated_uidplus_data_size: 10_000,
-      }
-
-      version_defaults[0.4r] = {
-        sasl_ir: true,
-        parser_max_deprecated_uidplus_data_size: 1000,
-      }
-
-      version_defaults[0.5r] = {
-        enforce_logindisabled: true,
-        max_response_size: 512 << 20, # 512 MiB
-        responses_without_block: :warn,
-        parser_use_deprecated_uidplus_data: :up_to_max_size,
-        parser_max_deprecated_uidplus_data_size: 100,
-      }
-
-      version_defaults[0.6r] = {
-        responses_without_block: :frozen_dup,
-        parser_use_deprecated_uidplus_data: false,
-        parser_max_deprecated_uidplus_data_size: 0,
-      }
-
       AttrVersionDefaults.compile_version_defaults!
 
       if ($VERBOSE || $DEBUG) && self[:current].to_h != self[:default].to_h

lib/net/imap/config/attr_version_defaults.rb

@@ -38,13 +38,23 @@ module AttrVersionDefaults
 
         # :stopdoc: internal APIs only
 
+        def attr_accessor(name, defaults: nil, default: (unset = true), **kw)
+          unless unset
+            defaults ||= { 0.0r => default }
+          end
+          defaults&.each_pair do |version, default|
+            AttrVersionDefaults.version_defaults[version] ||= {}
+            AttrVersionDefaults.version_defaults[version][name] = default
+          end
+          super(name, **kw)
+        end
+
         def self.compile_version_defaults!
           # Temporarily assign Config.default, enabling #load_defaults(:default)
           version_defaults[:default] = Config.default
           # Use #load_defaults so some attributes are inherited from global.
           version_defaults[:default] = Config.new.load_defaults(:default).freeze
-          version_defaults[0.0r]     = Config[:default].dup
-            .update(**version_defaults[0.0r]).freeze
+          version_defaults[0.0r]     = Config[version_defaults.fetch(0.0r)]
 
           VERSIONS.each_cons(2) do |prior, version|
             updates = version_defaults[version]