From 86081156a1148da78d741cc5c150e7294a66113e Mon Sep 17 00:00:00 2001
From: Taylor Blau <me@ttaylorr.com>
Date: Tue, 31 Jul 2018 13:24:17 -0500
Subject: [PATCH] tq: display a warning message upon HTTP 422

---
 t/t-content-type.sh  | 21 +++++++++++++++++++++
 tq/basic_upload.go   | 11 +++++++++++
 tq/transfer_queue.go | 32 ++++++++++++++++++++++++++++++--
 3 files changed, 62 insertions(+), 2 deletions(-)

diff --git a/t/t-content-type.sh b/t/t-content-type.sh
index 6eab4020a0..0100d0b97d 100755
--- a/t/t-content-type.sh
+++ b/t/t-content-type.sh
@@ -44,3 +44,24 @@ begin_test "content-type: is disabled by configuration"
   [ 1 -eq "$(grep -c "Content-Type: application/zip" push.log)" ]
 )
 end_test
+
+begin_test "content-type: warning message"
+(
+  set -e
+
+  reponame="content-type-warning-message"
+  setup_remote_repo "$reponame"
+  clone_repo "$reponame" "$reponame"
+
+  git lfs track "*.txt"
+  printf "status-storage-422" > a.txt
+
+  git add .gitattributes a.txt
+  git commit -m "initial commit"
+  git push origin master 2>&1 | tee push.log
+
+  grep "info: Uploading failed due to unsupported Content-Type header(s)." push.log
+  grep "info: Consider disabling Content-Type detection with:" push.log
+  grep "info:   $ git config lfs.contenttype false" push.log
+)
+end_test
diff --git a/tq/basic_upload.go b/tq/basic_upload.go
index e5de3fd237..85575654c5 100644
--- a/tq/basic_upload.go
+++ b/tq/basic_upload.go
@@ -102,6 +102,17 @@ func (a *basicUploadAdapter) DoTransfer(ctx interface{}, t *Transfer, cb Progres
 	req = a.apiClient.LogRequest(req, "lfs.data.upload")
 	res, err := a.doHTTP(t, req)
 	if err != nil {
+		if errors.IsUnprocessableEntityError(err) {
+			// If we got an HTTP 422, we do _not_ want to retry the
+			// request later below, because it is likely that the
+			// implementing server does not support non-standard
+			// Content-Type headers.
+			//
+			// Instead, return immediately and wait for the
+			// *tq.TransferQueue to report an error message.
+			return err
+		}
+
 		// We're about to return a retriable error, meaning that this
 		// transfer will either be retried, or it will fail.
 		//
diff --git a/tq/transfer_queue.go b/tq/transfer_queue.go
index 81367ceb77..eba9f67707 100644
--- a/tq/transfer_queue.go
+++ b/tq/transfer_queue.go
@@ -1,6 +1,7 @@
 package tq
 
 import (
+	"fmt"
 	"os"
 	"sort"
 	"sync"
@@ -127,6 +128,11 @@ type TransferQueue struct {
 	wait     sync.WaitGroup
 	manifest *Manifest
 	rc       *retryCounter
+
+	// unsupportedContentType indicates whether the transfer queue ever saw
+	// an HTTP 422 response indicating that their upload destination does
+	// not support Content-Type detection.
+	unsupportedContentType bool
 }
 
 // objects holds a set of objects.
@@ -651,8 +657,13 @@ func (q *TransferQueue) handleTransferResult(
 			// If the error wasn't retriable, OR the object has
 			// exceeded its retry budget, it will be NOT be sent to
 			// the retry channel, and the error will be reported
-			// immediately.
-			q.errorc <- res.Error
+			// immediately (unless the error is in response to a
+			// HTTP 422).
+			if errors.IsUnprocessableEntityError(res.Error) {
+				q.unsupportedContentType = true
+			} else {
+				q.errorc <- res.Error
+			}
 			q.wait.Done()
 		}
 	} else {
@@ -763,6 +774,17 @@ func (q *TransferQueue) toAdapterCfg(e lfsapi.Endpoint) AdapterConfig {
 	}
 }
 
+var (
+	// contentTypeWarning is the message printed when a server returns an
+	// HTTP 422 at the end of a push.
+	contentTypeWarning = []string{
+		"Uploading failed due to unsupported Content-Type header(s).",
+		"Consider disabling Content-Type detection with:",
+		"",
+		"  $ git config lfs.contenttype false",
+	}
+)
+
 // Wait waits for the queue to finish processing all transfers. Once Wait is
 // called, Add will no longer add transfers to the queue. Any failed
 // transfers will be automatically retried once.
@@ -781,6 +803,12 @@ func (q *TransferQueue) Wait() {
 
 	q.meter.Flush()
 	q.errorwait.Wait()
+
+	if q.unsupportedContentType {
+		for _, line := range contentTypeWarning {
+			fmt.Fprintf(os.Stderr, "info: %s\n", line)
+		}
+	}
 }
 
 // Watch returns a channel where the queue will write the value of each transfer