Merge pull request #9 from nerdrew/cvar-on-injecting-class

only set static dep on defining class

CHANGES.md

@@ -1,5 +1,31 @@
 # Change Log
 
+# v1.2.0
+
+- Ruby 3.x made it an error to override a class variable in a parent class. There was a bug with `inject_static` where
+  if a subclass was the first to call a static dependency, the class variable would only be set on that subclass (and
+  children of that subsclass). If the injecting class then called the static dependency, it would override the already
+  set child's class variable, which is now an error.
+
+  ```ruby
+  class Parent
+    include Interjectable
+    inject_static(:boom) { "goats" }
+  end
+
+  class Child < Parent; end
+
+  Child.boom # => sets Child's @@boom = "goats"
+  Parent.boom # => sets Parent's @@boom = "goats" and *clear* Child's @@boom.
+  Child.boom # => Error on Ruby 3.x because you are trying to read an overriden class variable.
+  ```
+
+  Fix: always set the class variable on the class that called `inject_static`.
+
+# v1.1.3
+
+- Fix `test_inject` for sub-sub-classes.
+
 # v1.1.2
 
 - Fix visibility issue with `Module.define_method` for Ruby < 2.5.0.

lib/interjectable.rb

@@ -64,26 +64,28 @@ def inject_static(dependency, &default_block)
         raise MethodAlreadyDefined, "#{dependency} is already defined"
       end
 
+      injecting_class = self
+
       cvar_name = :"@@#{dependency}"
       setter = :"#{dependency}="
 
       define_method(setter) do |value|
-        self.class.send(setter, value)
+        injecting_class.send(setter, value)
       end
 
       define_singleton_method(setter) do |value|
-        class_variable_set(cvar_name, value)
+        injecting_class.class_variable_set(cvar_name, value)
       end
 
       define_method(dependency) do
-        self.class.send(dependency)
+        injecting_class.send(dependency)
       end
 
       define_singleton_method(dependency) do
         if class_variable_defined?(cvar_name)
-          class_variable_get(cvar_name)
+          injecting_class.class_variable_get(cvar_name)
         else
-          class_variable_set(cvar_name, instance_eval(&default_block))
+          injecting_class.class_variable_set(cvar_name, instance_eval(&default_block))
         end
       end
     end

lib/interjectable/version.rb

@@ -1,5 +1,5 @@
 # frozen_string_literal: true
 
 module Interjectable
-  VERSION = "1.1.3"
+  VERSION = "1.2.0"
 end

spec/interjectable_spec.rb

@@ -170,6 +170,17 @@
           expect(subclass_instance.static_dependency).to eq(:some_other_value)
           expect(subclass.static_dependency).to eq(:some_other_value)
         end
+
+        it "does not error when lazily setting the dep from a subclass first" do
+          expect(subclass.static_dependency).to eq(:some_value)
+          expect(klass.static_dependency).to eq(:some_value)
+          expect(subclass.static_dependency).to eq(:some_value)
+        end
+
+        it "only defines the class variable on the injecting class" do
+          expect(subclass.static_dependency).to eq(:some_value)
+          expect(klass.class_variable_get(:@@static_dependency)).to eq(:some_value)
+        end
       end
     end
   end