From 1651c38b919944699bb8a705311c15b6ada8be11 Mon Sep 17 00:00:00 2001
From: Chris Smith <chrisdsmith@google.com>
Date: Mon, 6 Feb 2023 13:57:51 -0700
Subject: [PATCH] chore(transport): remove support for go runtimes earlier than
 1.16 (#1844)

---
 transport/http/configure_http2_go116.go     | 26 ---------------------
 transport/http/configure_http2_not_go116.go | 17 --------------
 transport/http/dial.go                      | 14 +++++++++--
 3 files changed, 12 insertions(+), 45 deletions(-)
 delete mode 100644 transport/http/configure_http2_go116.go
 delete mode 100644 transport/http/configure_http2_not_go116.go

diff --git a/transport/http/configure_http2_go116.go b/transport/http/configure_http2_go116.go
deleted file mode 100644
index 305a6929c88..00000000000
--- a/transport/http/configure_http2_go116.go
+++ /dev/null
@@ -1,26 +0,0 @@
-// Copyright 2021 Google LLC.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-//go:build go1.16
-// +build go1.16
-
-package http
-
-import (
-	"net/http"
-	"time"
-
-	"golang.org/x/net/http2"
-)
-
-// configureHTTP2 configures the ReadIdleTimeout HTTP/2 option for the
-// transport. This allows broken idle connections to be pruned more quickly,
-// preventing the client from attempting to re-use connections that will no
-// longer work.
-func configureHTTP2(trans *http.Transport) {
-	http2Trans, err := http2.ConfigureTransports(trans)
-	if err == nil {
-		http2Trans.ReadIdleTimeout = time.Second * 31
-	}
-}
diff --git a/transport/http/configure_http2_not_go116.go b/transport/http/configure_http2_not_go116.go
deleted file mode 100644
index d2742d283a6..00000000000
--- a/transport/http/configure_http2_not_go116.go
+++ /dev/null
@@ -1,17 +0,0 @@
-// Copyright 2021 Google LLC.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-//go:build !go1.16
-// +build !go1.16
-
-package http
-
-import (
-	"net/http"
-)
-
-// configureHTTP2 configures the ReadIdleTimeout HTTP/2 option for the
-// transport. The interface to do this is only available in Go 1.16 and up, so
-// this performs a no-op.
-func configureHTTP2(trans *http.Transport) {}
diff --git a/transport/http/dial.go b/transport/http/dial.go
index cab709f0c05..47568a4061d 100644
--- a/transport/http/dial.go
+++ b/transport/http/dial.go
@@ -16,6 +16,7 @@ import (
 	"time"
 
 	"go.opencensus.io/plugin/ochttp"
+	"golang.org/x/net/http2"
 	"golang.org/x/oauth2"
 	"google.golang.org/api/googleapi/transport"
 	"google.golang.org/api/internal"
@@ -175,13 +176,22 @@ func defaultBaseTransport(ctx context.Context, clientCertSource cert.Source) htt
 		}
 	}
 
-	// If possible, configure http2 transport in order to use ReadIdleTimeout
-	// setting. This can only be done in Go 1.16 and up.
 	configureHTTP2(trans)
 
 	return trans
 }
 
+// configureHTTP2 configures the ReadIdleTimeout HTTP/2 option for the
+// transport. This allows broken idle connections to be pruned more quickly,
+// preventing the client from attempting to re-use connections that will no
+// longer work.
+func configureHTTP2(trans *http.Transport) {
+	http2Trans, err := http2.ConfigureTransports(trans)
+	if err == nil {
+		http2Trans.ReadIdleTimeout = time.Second * 31
+	}
+}
+
 // fallbackBaseTransport is used in <go1.13 as well as in the rare case if
 // http.DefaultTransport has been reassigned something that's not a
 // *http.Transport.