Nb/nil issues ruby 3

lib/liquid/block_body.rb

@@ -127,7 +127,7 @@ def render_to_output_buffer(context, output)
 
         case node
         when String
-          output << node
+          output.force_encoding('UTF-8') << node.force_encoding('UTF-8')
         when Variable
           render_node(context, output, node)
         when Block

lib/liquid/tag.rb

@@ -58,7 +58,12 @@ def disabled_error_message
     # of the `render_to_output_buffer` method will become the default and the `render`
     # method will be removed.
     def render_to_output_buffer(context, output)
-      output << render(context)
+      rendered = render(context)
+      if output.nil?
+        output = rendered.to_s
+      else
+        output << rendered.to_s
+      end
       output
     end
 

lib/liquid/variable.rb

@@ -94,14 +94,31 @@ def render(context)
     def render_to_output_buffer(context, output)
       obj = render(context)
 
+      if output.nil?
+        output = +''
+      elsif output.frozen?
+        raise LiquidError, "Cannot mutate frozen output buffer"
+      end
+
       if obj.is_a?(Array)
         output << obj.join
+      elsif obj.kind_of?(Hash)
+        output << obj.to_s
       elsif obj.nil?
+        # do nothing
+      elsif obj.kind_of?(String)
+        output << obj
       else
-        output << obj.to_s
+        output << obj.try(:to_s) || ""
       end
 
       output
+    rescue Encoding::CompatibilityError => e
+      if obj.kind_of?(String)
+        output.force_encoding('UTF-8') << obj
+      else
+        raise e
+      end
     end
 
     def disabled?(_context)