context: make DeadlineExceeded have a Timeout method
Fixes #14238
Change-Id: I1538bfb5cfa63e36a89df1f6eb9f5a0dcafb6ce5
Reviewed-on: https://go-review.googlesource.com/23256
Reviewed-by: Dave Cheney <dave@cheney.net>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
diff --git a/src/context/context.go b/src/context/context.go
index 9ff1950..169db74 100644
--- a/src/context/context.go
+++ b/src/context/context.go
@@ -144,7 +144,13 @@
// DeadlineExceeded is the error returned by Context.Err when the context's
// deadline passes.
-var DeadlineExceeded = errors.New("context deadline exceeded")
+var DeadlineExceeded error = deadlineExceededError{}
+
+type deadlineExceededError struct{}
+
+func (deadlineExceededError) Error() string { return "context deadline exceeded" }
+
+func (deadlineExceededError) Timeout() bool { return true }
// An emptyCtx is never canceled, has no values, and has no deadline. It is not
// struct{}, since vars of this type must have distinct addresses.
