Multiple writes to Rack::Response result in incorrect content-length header in Rack 3 about rack HOT 4 CLOSED

Without digging into it, it appears that the latter @length += chunk.bytesize is incorrect. Do you think removing it is the correct course of action?

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I'm actually not sure I understand the intention of the existing code, in particular why @buffered is set to nil in the constructor and lazily initialized later. Since I may be missing the point of @buffered, take what follows with a grain of salt.

The problem I see is that there is a missing assignment of @buffered in one of the conditional branches within buffered_body!.

Abbreviated, the code currently looks like this:

if @buffered.nil?
  if @body.is_a?(Array)
    # ...
    # ⚠️ @buffered is not set in this branch
  elsif @body.respond_to?(:each)
    # ...
    @buffered = true
  else
    @buffered = false
  end
end

It seems like the point of this code was to lazily init @buffered to true or false, but currently that isn't happening in the first branch. So I think the fix is to add @buffered = true, like this:

--- lib/rack/response.rb
+++ lib/rack/response.rb
@@ -318,12 +318,14 @@ module Rack
           if @body.is_a?(Array)
             # The user supplied body was an array:
             @body = @body.compact
             @body.each do |part|
               @length += part.to_s.bytesize
             end
+
+            @buffered = true
           elsif @body.respond_to?(:each)
             # Turn the user supplied body into a buffered array:
             body = @body
             @body = Array.new
 
             body.each do |part|

With this one-line change, I get the correct content-length result when running my reproduction script.

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Do you mind making a PR?

from rack.

OK, I've opened PR #2150

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