From f002be148e1377709ed28b8e80c5db76ee2fa410 Mon Sep 17 00:00:00 2001
From: Matt Tanous <mtanous22@gmail.com>
Date: Wed, 25 Jul 2018 17:04:34 -0400
Subject: Add :allow_nil option to delegate_missing_to; use in ActiveStorage
attachment
---
activesupport/CHANGELOG.md | 7 ++++++-
.../lib/active_support/core_ext/module/delegation.rb | 11 ++++++++---
activesupport/test/core_ext/module_test.rb | 14 ++++++++++++++
3 files changed, 28 insertions(+), 4 deletions(-)
(limited to 'activesupport')
diff --git a/activesupport/CHANGELOG.md b/activesupport/CHANGELOG.md
index e494f66c5a..3d1dd41085 100644
--- a/activesupport/CHANGELOG.md
+++ b/activesupport/CHANGELOG.md
@@ -1,3 +1,9 @@
+* `delegate_missing_to` would raise a `DelegationError` if the object
+ delegated to was `nil`. Now the `allow_nil` option has been added to enable
+ the user to specify they want `nil` returned in this case.
+
+ *Matthew Tanous*
+
* `truncate` would return the original string if it was too short to be truncated
and a frozen string if it were long enough to be truncated. Now truncate will
consistently return an unfrozen string regardless. This behavior is consistent
@@ -19,5 +25,4 @@
*Jordan Thomas*
-
Please check [6-0-stable](https://github.com/rails/rails/blob/6-0-stable/activesupport/CHANGELOG.md) for previous changes.
diff --git a/activesupport/lib/active_support/core_ext/module/delegation.rb b/activesupport/lib/active_support/core_ext/module/delegation.rb
index 9fe7f8fe01..2f88010d27 100644
--- a/activesupport/lib/active_support/core_ext/module/delegation.rb
+++ b/activesupport/lib/active_support/core_ext/module/delegation.rb
@@ -274,8 +274,9 @@ class Module
# variables, methods, constants, etc.
#
# The delegated method must be public on the target, otherwise it will
- # raise +NoMethodError+.
- def delegate_missing_to(target)
+ # raise +DelegationError+. If you wish to instead return +nil+,
+ # use the <tt>:allow_nil</tt> option.
+ def delegate_missing_to(target, allow_nil: nil)
target = target.to_s
target = "self.#{target}" if DELEGATION_RESERVED_METHOD_NAMES.include?(target)
@@ -295,7 +296,11 @@ class Module
super
rescue NoMethodError
if #{target}.nil?
- raise DelegationError, "\#{method} delegated to #{target}, but #{target} is nil"
+ if #{allow_nil == true}
+ return nil
+ else
+ raise DelegationError, "\#{method} delegated to #{target}, but #{target} is nil"
+ end
else
raise
end
diff --git a/activesupport/test/core_ext/module_test.rb b/activesupport/test/core_ext/module_test.rb
index 04692f1484..6e341480d1 100644
--- a/activesupport/test/core_ext/module_test.rb
+++ b/activesupport/test/core_ext/module_test.rb
@@ -92,6 +92,16 @@ DecoratedTester = Struct.new(:client) do
delegate_missing_to :client
end
+class DecoratedMissingAllowNil
+ delegate_missing_to :case, allow_nil: true
+
+ attr_reader :case
+
+ def initialize(kase)
+ @case = kase
+ end
+end
+
class DecoratedReserved
delegate_missing_to :case
@@ -382,6 +392,10 @@ class ModuleTest < ActiveSupport::TestCase
assert_equal "name delegated to client, but client is nil", e.message
end
+ def test_delegate_missing_to_returns_nil_if_allow_nil_and_nil_target
+ assert_nil DecoratedMissingAllowNil.new(nil).name
+ end
+
def test_delegate_missing_to_affects_respond_to
assert_respond_to DecoratedTester.new(@david), :name
assert_not_respond_to DecoratedTester.new(@david), :private_name
--
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