testing: add doc to not call Init concurrently

Change-Id: I2e218805fbe4858be125df97bdaf921799315799
GitHub-Last-Rev: 32b798d75f7ec0f72e18a65932ad93d8e5f1040a
GitHub-Pull-Request: golang/go#62410
Reviewed-on: https://go-review.googlesource.com/c/go/+/525015
Auto-Submit: Ian Lance Taylor <iant@golang.org>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Bryan Mills <bcmills@google.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Ian Lance Taylor <iant@google.com>

diff --git a/src/testing/testing.go b/src/testing/testing.go
index fcf7048f23404db6d21835c8e17da539f912556d..1bc8aff00d1085a78d9175bdb3fa502e81e08fdb 100644 (file)
--- a/src/testing/testing.go
+++ b/src/testing/testing.go
@@ -398,7 +398,7 @@ var initRan bool
 // the "go test" command before running test functions, so Init is only needed
 // when calling functions such as Benchmark without using "go test".
 //
-// Init has no effect if it was already called.
+// Init is not safe to call concurrently. It has no effect if it was already called.
 func Init() {
        if initRan {
                return