os/user: fix formatting of error group lookup message

It was failing like "unknown groupid ᎈ|" instead of "unknown groupid
5000" due to the conversion from int to string.

Updates #14806

Change-Id: I83e4b478ff628ad4053573a9f32b3fadce22e847
Reviewed-on: https://go-review.googlesource.com/20642
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>

diff --git a/src/os/user/lookup_unix.go b/src/os/user/lookup_unix.go
index 579e0d5cb40d40b13112c159eabc7865efaab5b1..97b649cdad63c1e33b8dfcdf84f41560d1fdf0c7 100644 (file)
--- a/src/os/user/lookup_unix.go
+++ b/src/os/user/lookup_unix.go
@@ -183,7 +183,7 @@ func lookupUnixGid(gid int) (*Group, error) {
                return nil, fmt.Errorf("user: lookup groupid %d: %v", gid, err)
        }
        if result == nil {
-               return nil, UnknownGroupIdError(gid)
+               return nil, UnknownGroupIdError(strconv.Itoa(gid))
        }
        return buildGroup(&grp), nil
 }