From a9a5bb5bc501d06f73507b20466aa0f4982d1be0 Mon Sep 17 00:00:00 2001
From: Neil Alexander <neilalexander@users.noreply.github.com>
Date: Fri, 21 Aug 2020 10:37:21 +0100
Subject: [PATCH] Add note to Writer documentation

---
 internal/sqlutil/writer.go | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/internal/sqlutil/writer.go b/internal/sqlutil/writer.go
index 6e5ff5705..5d93fef4d 100644
--- a/internal/sqlutil/writer.go
+++ b/internal/sqlutil/writer.go
@@ -36,6 +36,9 @@ import "database/sql"
 // will ALWAYS be nil in this mode. This is useful if you just
 // want to perform a single query on an already-prepared statement
 // without the overhead of opening a new transaction to do it in.
+//
+// You MUST take particular care not to call Do() from within f()
+// on the same Writer, or it will likely result in a deadlock.
 type Writer interface {
 	// Queue up one or more database write operations within the
 	// provided function to be executed when it is safe to do so.