Update comments that reference PatchSliceOfMaps

To reference decode.HookWeakDecodeFromSlice instead.

Also removes a step from the adding config fields checklist which is
no longer necessary.

agent/config/runtime_test.go

@@ -2499,8 +2499,8 @@ func TestConfigFlagsAndEdgecases(t *testing.T) {
 		},
 
 		{
-			// This tests that we correct added the nested paths to arrays of objects
-			// to the exceptions in PatchSliceOfMaps in config.go (for single service)
+			// Test that slices in structured config are preserved by
+			// decode.HookWeakDecodeFromSlice.
 			desc: "service.connectsidecar_service with checks and upstreams",
 			args: []string{
 				`-data-dir=` + dataDir,
@@ -2628,8 +2628,8 @@ func TestConfigFlagsAndEdgecases(t *testing.T) {
 			},
 		},
 		{
-			// This tests that we correct added the nested paths to arrays of objects
-			// to the exceptions in PatchSliceOfMaps in config.go (for service*s*)
+			// Test that slices in structured config are preserved by
+			// decode.HookWeakDecodeFromSlice.
 			desc: "services.connect.sidecar_service with checks and upstreams",
 			args: []string{
 				`-data-dir=` + dataDir,

agent/xds/clusters.go

@@ -523,13 +523,8 @@ func (s *Server) makeUpstreamClustersForDiscoveryChain(
 // arbitrary proto3 json format string or an error if it's invalid.
 //
 // For now we only support embedding in JSON strings because of the hcl parsing
-// pain (see config.go comment above call to PatchSliceOfMaps). Until we
-// refactor config parser a _lot_ user's opaque config that contains arrays will
-// be mangled. We could actually fix that up in mapstructure which knows the
-// type of the target so could resolve the slices to singletons unambiguously
-// and it would work for us here... but we still have the problem that the
-// config would render incorrectly in general in our HTTP API responses so we
-// really need to fix it "properly".
+// pain (see Background section in the comment for decode.HookWeakDecodeFromSlice).
+// This may be fixed in decode.HookWeakDecodeFromSlice in the future.
 //
 // When we do that we can support just nesting the config directly into the
 // JSON/hcl naturally but this is a stop-gap that gets us an escape hatch

agent/xds/listeners.go

@@ -355,13 +355,8 @@ func makeListener(name, addr string, port int) *envoy.Listener {
 // arbitrary proto3 json format string or an error if it's invalid.
 //
 // For now we only support embedding in JSON strings because of the hcl parsing
-// pain (see config.go comment above call to PatchSliceOfMaps). Until we
-// refactor config parser a _lot_ user's opaque config that contains arrays will
-// be mangled. We could actually fix that up in mapstructure which knows the
-// type of the target so could resolve the slices to singletons unambiguously
-// and it would work for us here... but we still have the problem that the
-// config would render incorrectly in general in our HTTP API responses so we
-// really need to fix it "properly".
+// pain (see Background section in the comment for decode.HookWeakDecodeFromSlice).
+// This may be fixed in decode.HookWeakDecodeFromSlice in the future.
 //
 // When we do that we can support just nesting the config directly into the
 // JSON/hcl naturally but this is a stop-gap that gets us an escape hatch

contributing/checklist-adding-config-fields.md

@@ -55,12 +55,6 @@ There are four specific cases covered with increasing complexity:
            state for client agent's RPC client.
       - [ ] Add a test to `agent/agent_test.go` similar to others with prefix
         `TestAgent_reloadConfig*`.
- - [ ] **If** the new config field(s) include an array of structs or maps.
-      - [ ] Add the path to the call to `lib.PatchSliceOfMaps` in Parse in
-        `agent/config/config.go`.
-      - [ ] If none of the tests in `agent/config/runtime_test.go` failed before you did that,
-        then you didn't actually test the slice part yet, go back and add tests
-        that populate that slice.
  - [ ] Add documentation to `website/source/docs/agent/options.html.md`.
 
 Done! You can now use your new field in a client agent by accessing