From adb6170b77ce4a4ea156f0198678444f61b39255 Mon Sep 17 00:00:00 2001
From: Will Jordan <wjordan@users.noreply.github.com>
Date: Fri, 21 Feb 2020 08:26:38 -0800
Subject: [PATCH] Rescue IO::WaitReadable instead of EAGAIN for blocking read
 (#2121)

* Add test for waiting with an open client connection

* Rescue IO::WaitReadable instead of EAGAIN for blocking read
On Windows, `read_nonblock` raises `Errno::EWOULDBLOCK` if a blocking read would occur, which is a different value from `Errno::EAGAIN`. Both of these errors are extended by `IO::WaitReadable` which is Ruby's recommended exception class for retrying `read_nonblock`.
---
 History.md               |  1 +
 lib/puma/client.rb       |  4 ++--
 test/test_puma_server.rb | 13 +++++++++++++
 3 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/History.md b/History.md
index 142e8068d6..9a38780c9a 100644
--- a/History.md
+++ b/History.md
@@ -13,6 +13,7 @@
   * Windows update extconf.rb for use with ssp and varied Ruby/MSYS2 combinations (#2069)
   * Preserve `BUNDLE_GEMFILE` env var when using `prune_bundler` (#1893)
   * Send 408 request timeout even when queue requests is disabled (#2119)
+  * Rescue IO::WaitReadable instead of EAGAIN for blocking read (#2121)
 
 * Refactor
   * Remove unused loader argument from Plugin initializer (#2095)
diff --git a/lib/puma/client.rb b/lib/puma/client.rb
index 8a37736aaf..7b013732ab 100644
--- a/lib/puma/client.rb
+++ b/lib/puma/client.rb
@@ -153,7 +153,7 @@ def try_to_finish
 
       begin
         data = @io.read_nonblock(CHUNK_SIZE)
-      rescue Errno::EAGAIN
+      rescue IO::WaitReadable
         return false
       rescue SystemCallError, IOError, EOFError
         raise ConnectionError, "Connection error detected during read"
@@ -349,7 +349,7 @@ def read_body
 
       begin
         chunk = @io.read_nonblock(want)
-      rescue Errno::EAGAIN
+      rescue IO::WaitReadable
         return false
       rescue SystemCallError, IOError
         raise ConnectionError, "Connection error detected during read"
diff --git a/test/test_puma_server.rb b/test/test_puma_server.rb
index a43a3c974a..eb55f110e6 100644
--- a/test/test_puma_server.rb
+++ b/test/test_puma_server.rb
@@ -754,4 +754,17 @@ def test_request_body_wait_chunked
     # it is set to a reasonable number.
     assert_operator request_body_wait, :>=, 900
   end
+
+  def test_open_connection_wait
+    server_run app: ->(_) { [200, {}, ["Hello"]] }
+    s = send_http nil
+    sleep 0.1
+    s << "GET / HTTP/1.0\r\n\r\n"
+    assert_equal 'Hello', s.readlines.last
+  end
+
+  def test_open_connection_wait_no_queue
+    @server = Puma::Server.new @app, @events, queue_requests: false
+    test_open_connection_wait
+  end
 end