Found an issue with thread's not inheriting on_warning, made on_warni…

…ng not thread safe to fix this

README.md

@@ -65,9 +65,10 @@ end
 
 ## Thread-safe
 
-This gem is tested to be thread safe with one known exception.
+This gem is tested to be thread safe with a couple known exceptions.
 
-`PedantMysql2.ignore` is not thread safe and should only be called during intialization of your app. Changing this within a thread while another is updating it could be problematic.
+`PedantMysql2.ignore` is not thread safe and should only be called during initialization of your app. Changing this within a thread while another is updating it could be problematic.
+`PedantMysql2.on_warning=` is not thread safe, this should also be called only during initialization.
 
 If you find any other parts that are not thread-safe, please create an issue or PR.
 

lib/pedant_mysql2.rb

@@ -32,11 +32,11 @@ def warn(warning)
     end
 
     def on_warning
-      Thread.current[:__pedant_mysql2_on_warning]
+      Thread.current[:__pedant_mysql2_on_warning] || @_on_warning
     end
 
     def on_warning=(new_proc)
-      Thread.current[:__pedant_mysql2_on_warning] = new_proc
+      @_on_warning = new_proc
     end
 
     protected
@@ -51,19 +51,23 @@ def ignored?(warning)
 
     def setup_capture
       Thread.current[:__pedant_mysql2_warnings] = []
-      self.on_warning = lambda { |warning| Thread.current[:__pedant_mysql2_warnings] << warning }
+      self.thread_on_warning = lambda { |warning| Thread.current[:__pedant_mysql2_warnings] << warning }
     end
 
     def captured_warnings
       Thread.current[:__pedant_mysql2_warnings]
     end
 
     def backup_warnings
-      [captured_warnings, on_warning]
+      [captured_warnings, Thread.current[:__pedant_mysql2_on_warning]]
     end
 
     def restore_warnings(warnings)
-      Thread.current[:__pedant_mysql2_warnings], self.on_warning = *warnings
+      Thread.current[:__pedant_mysql2_warnings], self.thread_on_warning = *warnings
+    end
+
+    def thread_on_warning=(new_proc)
+      Thread.current[:__pedant_mysql2_on_warning] = new_proc
     end
   end
 end

spec/adapter_spec.rb

@@ -125,6 +125,17 @@ def method_missing(method_name,*args)
     thread.join
   end
 
+  it 'should inherit on_warning from parent thread' do
+    PedantMysql2.silence_warnings!
+    thread = Thread.new do
+      expect {
+        execute_with_warning
+      }.to_not raise_error
+    end
+
+    thread.join
+  end
+
   describe MysqlWarning do
 
     subject do