In normal operations there is a read/write race related to request
QueryOptions fields. An example race:
WARNING: DATA RACE
Read at 0x00c000836950 by goroutine 30:
github.com/hashicorp/consul/agent/structs.(*ServiceConfigRequest).CacheInfo()
/go/src/github.com/hashicorp/consul/agent/structs/config_entry.go:506 +0x109
github.com/hashicorp/consul/agent/cache.(*Cache).getWithIndex()
/go/src/github.com/hashicorp/consul/agent/cache/cache.go:262 +0x5c
github.com/hashicorp/consul/agent/cache.(*Cache).notifyBlockingQuery()
/go/src/github.com/hashicorp/consul/agent/cache/watch.go:89 +0xd7
Previous write at 0x00c000836950 by goroutine 147:
github.com/hashicorp/consul/agent/cache-types.(*ResolvedServiceConfig).Fetch()
/go/src/github.com/hashicorp/consul/agent/cache-types/resolved_service_config.go:31 +0x219
github.com/hashicorp/consul/agent/cache.(*Cache).fetch.func1()
/go/src/github.com/hashicorp/consul/agent/cache/cache.go:495 +0x112
This patch does a lightweight copy of the request struct so that the
embedded QueryOptions fields that are mutated during Fetch() are scoped
to just that one RPC.
20eb0d3e94