From 5ad25712a5dd8f8b8d8c005edbcc089973ebe57a Mon Sep 17 00:00:00 2001
From: Oleg Jukovec <oleg.jukovec@tarantool.org>
Date: Thu, 8 Feb 2024 19:04:08 +0300
Subject: [PATCH] api: remove Future.Err()

The method causes an improper error handling because it returns an error
only from a client side. Therefore, it is not enough to simply check
the error to find out that the request was not completed.

A user should check an error from `Future.Get()` or
`Future.GetTyped()`. In addition, the user can find out whether there
was an error without decoding the response body with
`Future.GetResponse()`, see `ExampleErrorNo`.
---
 CHANGELOG.md | 1 +
 README.md    | 3 +++
 future.go    | 8 --------
 3 files changed, 4 insertions(+), 8 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index c71a63146..4e7819d0f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -127,6 +127,7 @@ Versioning](http://semver.org/spec/v2.0.0.html) except to the first release.
 - `Schema` field from the `Connection` struct (#7)
 - `OkCode` and `PushCode` constants (#237)
 - SSL support (#301)
+- `Future.Err()` method (#382)
 
 ### Fixed
 
diff --git a/README.md b/README.md
index 85ca776a1..d11c6a0e8 100644
--- a/README.md
+++ b/README.md
@@ -348,6 +348,9 @@ for an `ops` field. `*Operations` needs to be used instead.
 * `Future` constructors now accept `Request` as their argument.
 * Methods `AppendPush` and `SetResponse` accepts response `Header` and data
   as their arguments.
+* Method `Err` removed because it provokes an invalid error checking. You need
+  to check an error from `Get`, `GetTyped` or `GetResponse` with an addition
+  check a value of `Response.Header().Error`.
 
 #### Connector changes
 
diff --git a/future.go b/future.go
index 1b9f2ed14..64e2805f1 100644
--- a/future.go
+++ b/future.go
@@ -266,11 +266,3 @@ func (fut *Future) WaitChan() <-chan struct{} {
 	}
 	return fut.done
 }
-
-// Err returns error set on Future.
-// It waits for future to be set.
-// Note: it doesn't decode body, therefore decoding error are not set here.
-func (fut *Future) Err() error {
-	fut.wait()
-	return fut.err
-}