From 3610eddf40b5f1abcce3cfede5839c1100290163 Mon Sep 17 00:00:00 2001
From: Eric Entzel <eric@ubermac.net>
Date: Mon, 14 Sep 2026 11:49:13 -0500
Subject: [PATCH] fix: add explicit RDMA build constraints

Gate native RDMA, cuObject, and cuobjclient implementations behind the
rdma build tag while keeping fallback stubs available for standard builds.
Preserve the separate cuobjclient_host configuration, clarify unsupported
platform errors, and update Makefile RDMA targets to pass the required tags
and disable VCS stamping.

Co-authored-by: Ben McClelland <ben.mcclelland@versity.com>
---
 Makefile                                   | 12 ++++++++----
 cubackend/cuserver.go                      |  2 +-
 cubackend/cuserver_stub.go                 |  2 +-
 cuobjclient/session_host_linux.go          |  2 +-
 cuobjclient/session_linux.go               |  2 +-
 cuobjclient/session_stub.go                |  8 ++++----
 cuobjclient/transport.go                   |  2 +-
 rdma/hostclient/client_linux.go            |  2 +-
 rdma/hostclient/client_stub.go             |  2 +-
 rdma/rcroutes/admin_linux.go               |  2 +-
 rdma/rcroutes/admin_stub.go                |  2 +-
 rdma/rcroutes/errors_linux.go              |  2 +-
 rdma/rcroutes/errors_mapping_linux_test.go |  2 +-
 rdma/rcroutes/errors_stub.go               |  2 +-
 rdma/rcroutes/ops_linux.go                 |  2 +-
 rdma/rcroutes/ops_linux_test.go            |  2 +-
 rdma/rcroutes/routes_linux.go              |  2 +-
 rdma/rcroutes/routes_stub.go               |  2 +-
 rdma/rcserver/rcserver_cgo_linux_test.go   |  2 +-
 rdma/rcserver/rcserver_linux.go            |  2 +-
 rdma/rcserver/rcserver_stub.go             |  2 +-
 rdma/rdma.go                               |  2 +-
 rdma/rdma_stub.go                          |  2 +-
 23 files changed, 33 insertions(+), 29 deletions(-)

diff --git a/Makefile b/Makefile
index 5eed900e..47f15fb9 100644
--- a/Makefile
+++ b/Makefile
@@ -111,7 +111,7 @@ vgwrdma: $(VGWRDMA_WRAPPER_LIB) $(RCSERVER_LIB)
 	CGO_ENABLED=1 \
 	CGO_CFLAGS="$(VGWRDMA_RDMA_CGO_CFLAGS)" \
 	CGO_LDFLAGS="$(VGWRDMA_RDMA_CGO_LDFLAGS)" \
-		$(GOBUILD) -buildvcs=false $(LDFLAGS) -o $(VGWRDMA_BIN) $(VGWRDMA_CMD)
+		$(GOBUILD) -buildvcs=false -tags rdma $(LDFLAGS) -o $(VGWRDMA_BIN) $(VGWRDMA_CMD)
 
 .PHONY: cuobjtest
 cuobjtest: cuobjtest-gpu
@@ -121,12 +121,12 @@ cuobjtest-gpu: $(CUOBJCLIENT_WRAPPER_LIB)
 	CGO_ENABLED=1 \
 	CGO_CFLAGS="$(CUOBJCLIENT_CGO_CFLAGS)" \
 	CGO_LDFLAGS="$(CUOBJCLIENT_CGO_LDFLAGS)" \
-		$(GOBUILD) -buildvcs=false $(LDFLAGS) -o $(CUOBJTEST_BIN) $(CUOBJTEST_CMD)
+		$(GOBUILD) -buildvcs=false -tags rdma $(LDFLAGS) -o $(CUOBJTEST_BIN) $(CUOBJTEST_CMD)
 
 .PHONY: cuobjtest-host
 cuobjtest-host: $(HOSTCLIENT_WRAPPER_LIB)
 	CGO_ENABLED=1 \
-		$(GOBUILD) -buildvcs=false -tags $(CUOBJTEST_HOST_TAG) $(LDFLAGS) -o $(CUOBJTEST_BIN) $(CUOBJTEST_CMD)
+		$(GOBUILD) -buildvcs=false -tags "rdma $(CUOBJTEST_HOST_TAG)" $(LDFLAGS) -o $(CUOBJTEST_BIN) $(CUOBJTEST_CMD)
 
 .PHONY: vgwrdma-builder-image
 vgwrdma-builder-image:
@@ -160,9 +160,13 @@ testbin:
 	$(GOBUILD) $(LDFLAGS) -o $(BIN) -cover -race cmd/$(BIN)/*.go
 
 .PHONY: test
-test: 
+test:
 	$(GOTEST) ./...
 
+.PHONY: rdmatest
+rdmatest: $(VGWRDMA_WRAPPER_LIB) $(CUOBJCLIENT_WRAPPER_LIB) $(HOSTCLIENT_WRAPPER_LIB) $(RCSERVER_LIB)
+	$(GOTEST) -tags rdma ./...
+
 .PHONY: check
 check:
 # note this requires staticcheck be in your PATH:
diff --git a/cubackend/cuserver.go b/cubackend/cuserver.go
index 0728d1a3..bceebf40 100644
--- a/cubackend/cuserver.go
+++ b/cubackend/cuserver.go
@@ -12,7 +12,7 @@
 // specific language governing permissions and limitations
 // under the License.
 
-//go:build linux && amd64 && cgo
+//go:build linux && amd64 && cgo && rdma
 
 package cubackend
 
diff --git a/cubackend/cuserver_stub.go b/cubackend/cuserver_stub.go
index 2964917b..81819165 100644
--- a/cubackend/cuserver_stub.go
+++ b/cubackend/cuserver_stub.go
@@ -12,7 +12,7 @@
 // specific language governing permissions and limitations
 // under the License.
 
-//go:build !(linux && amd64 && cgo)
+//go:build !(linux && amd64 && cgo && rdma)
 
 package cubackend
 
diff --git a/cuobjclient/session_host_linux.go b/cuobjclient/session_host_linux.go
index 151a2359..6bef90ed 100644
--- a/cuobjclient/session_host_linux.go
+++ b/cuobjclient/session_host_linux.go
@@ -12,7 +12,7 @@
 // specific language governing permissions and limitations
 // under the License.
 
-//go:build linux && amd64 && cgo && cuobjclient_host
+//go:build linux && amd64 && cgo && rdma && cuobjclient_host
 
 // This file implements the cuObjClient Session API on top of the host-memory
 // RDMA client (package rdma/hostclient). It contains no CUDA/GPU dependency and
diff --git a/cuobjclient/session_linux.go b/cuobjclient/session_linux.go
index 6b8374fb..db0f9857 100644
--- a/cuobjclient/session_linux.go
+++ b/cuobjclient/session_linux.go
@@ -12,7 +12,7 @@
 // specific language governing permissions and limitations
 // under the License.
 
-//go:build linux && amd64 && cgo && !cuobjclient_host
+//go:build linux && amd64 && cgo && rdma && !cuobjclient_host
 
 package cuobjclient
 
diff --git a/cuobjclient/session_stub.go b/cuobjclient/session_stub.go
index fb70b762..ea067e5c 100644
--- a/cuobjclient/session_stub.go
+++ b/cuobjclient/session_stub.go
@@ -12,7 +12,7 @@
 // specific language governing permissions and limitations
 // under the License.
 
-//go:build !(linux && amd64 && cgo)
+//go:build !(linux && amd64 && cgo && rdma)
 
 package cuobjclient
 
@@ -37,7 +37,7 @@ func NewSession(size int) (*Session, error) {
 	if size > MaxTransferSize {
 		return nil, fmt.Errorf("invalid size %d: exceeds MaxTransferSize (%d)", size, MaxTransferSize)
 	}
-	return nil, fmt.Errorf("cuobjclient: NewSession is only supported on linux/amd64 with cgo")
+	return nil, fmt.Errorf("cuobjclient: NewSession is only supported on linux/amd64 with cgo and the rdma build tag")
 }
 
 // Close is a no-op in the unsupported-platform stub.
@@ -52,7 +52,7 @@ func (s *Session) Upload(base *s3lib.Client, bucket, key string, src []byte) err
 	_ = bucket
 	_ = key
 	_ = src
-	return fmt.Errorf("cuobjclient: Upload is only supported on linux/amd64 with cgo")
+	return fmt.Errorf("cuobjclient: Upload is only supported on linux/amd64 with cgo and the rdma build tag")
 }
 
 // Download always returns an unsupported-platform error on this build.
@@ -62,5 +62,5 @@ func (s *Session) Download(base *s3lib.Client, bucket, key string, dst []byte) e
 	_ = bucket
 	_ = key
 	_ = dst
-	return fmt.Errorf("cuobjclient: Download is only supported on linux/amd64 with cgo")
+	return fmt.Errorf("cuobjclient: Download is only supported on linux/amd64 with cgo and the rdma build tag")
 }
diff --git a/cuobjclient/transport.go b/cuobjclient/transport.go
index 7a9cfd04..1ded8675 100644
--- a/cuobjclient/transport.go
+++ b/cuobjclient/transport.go
@@ -12,7 +12,7 @@
 // specific language governing permissions and limitations
 // under the License.
 
-//go:build linux && amd64 && cgo
+//go:build linux && amd64 && cgo && rdma
 
 // This file holds the S3 request plumbing shared by the GPU (session_linux.go)
 // and host-memory (session_host_linux.go) session implementations: both issue
diff --git a/rdma/hostclient/client_linux.go b/rdma/hostclient/client_linux.go
index aa4a553e..db5e2f8e 100644
--- a/rdma/hostclient/client_linux.go
+++ b/rdma/hostclient/client_linux.go
@@ -12,7 +12,7 @@
 // specific language governing permissions and limitations
 // under the License.
 
-//go:build linux && amd64 && cgo
+//go:build linux && amd64 && cgo && rdma
 
 // Package hostclient implements the client side of the cuObject RDMA DC
 // protocol using libibverbs + mlx5 direct verbs, with no CUDA/GPU dependency.
diff --git a/rdma/hostclient/client_stub.go b/rdma/hostclient/client_stub.go
index ff90fe25..e1fe3976 100644
--- a/rdma/hostclient/client_stub.go
+++ b/rdma/hostclient/client_stub.go
@@ -12,7 +12,7 @@
 // specific language governing permissions and limitations
 // under the License.
 
-//go:build !(linux && amd64 && cgo)
+//go:build !(linux && amd64 && cgo && rdma)
 
 // Package hostclient is stubbed on platforms without RDMA verbs support.
 package hostclient
diff --git a/rdma/rcroutes/admin_linux.go b/rdma/rcroutes/admin_linux.go
index eb60f23e..a87b4bf8 100644
--- a/rdma/rcroutes/admin_linux.go
+++ b/rdma/rcroutes/admin_linux.go
@@ -14,7 +14,7 @@
 // under the License.
 
 // Admin session snapshot route for the RC data plane.
-//go:build linux && amd64 && cgo
+//go:build linux && amd64 && cgo && rdma
 
 package rcroutes
 
diff --git a/rdma/rcroutes/admin_stub.go b/rdma/rcroutes/admin_stub.go
index b6d2f742..d9488fce 100644
--- a/rdma/rcroutes/admin_stub.go
+++ b/rdma/rcroutes/admin_stub.go
@@ -15,7 +15,7 @@
 
 // Admin session snapshot route (stub for platforms without RDMA
 // support).
-//go:build !(linux && amd64 && cgo)
+//go:build !(linux && amd64 && cgo && rdma)
 
 package rcroutes
 
diff --git a/rdma/rcroutes/errors_linux.go b/rdma/rcroutes/errors_linux.go
index 25b9f4a1..05f335ae 100644
--- a/rdma/rcroutes/errors_linux.go
+++ b/rdma/rcroutes/errors_linux.go
@@ -11,7 +11,7 @@
 // express or implied.  See the License for the specific language
 // governing permissions and limitations under the License.
 
-//go:build linux && amd64 && cgo
+//go:build linux && amd64 && cgo && rdma
 
 package rcroutes
 
diff --git a/rdma/rcroutes/errors_mapping_linux_test.go b/rdma/rcroutes/errors_mapping_linux_test.go
index 74adc866..0494ee1a 100644
--- a/rdma/rcroutes/errors_mapping_linux_test.go
+++ b/rdma/rcroutes/errors_mapping_linux_test.go
@@ -11,7 +11,7 @@
 // express or implied.  See the License for the specific language
 // governing permissions and limitations under the License.
 
-//go:build linux && amd64 && cgo
+//go:build linux && amd64 && cgo && rdma
 
 package rcroutes
 
diff --git a/rdma/rcroutes/errors_stub.go b/rdma/rcroutes/errors_stub.go
index 97e1c178..fe818fb9 100644
--- a/rdma/rcroutes/errors_stub.go
+++ b/rdma/rcroutes/errors_stub.go
@@ -11,7 +11,7 @@
 // express or implied.  See the License for the specific language
 // governing permissions and limitations under the License.
 
-//go:build !(linux && amd64 && cgo)
+//go:build !(linux && amd64 && cgo && rdma)
 
 package rcroutes
 
diff --git a/rdma/rcroutes/ops_linux.go b/rdma/rcroutes/ops_linux.go
index eb8370f0..fac111c6 100644
--- a/rdma/rcroutes/ops_linux.go
+++ b/rdma/rcroutes/ops_linux.go
@@ -13,7 +13,7 @@
 // specific language governing permissions and limitations
 // under the License.
 
-//go:build linux && amd64 && cgo
+//go:build linux && amd64 && cgo && rdma
 
 package rcroutes
 
diff --git a/rdma/rcroutes/ops_linux_test.go b/rdma/rcroutes/ops_linux_test.go
index ae1d6e65..de07ef19 100644
--- a/rdma/rcroutes/ops_linux_test.go
+++ b/rdma/rcroutes/ops_linux_test.go
@@ -13,7 +13,7 @@
 // specific language governing permissions and limitations
 // under the License.
 
-//go:build linux && amd64 && cgo
+//go:build linux && amd64 && cgo && rdma
 
 package rcroutes
 
diff --git a/rdma/rcroutes/routes_linux.go b/rdma/rcroutes/routes_linux.go
index 394d9893..8d136e8d 100644
--- a/rdma/rcroutes/routes_linux.go
+++ b/rdma/rcroutes/routes_linux.go
@@ -11,7 +11,7 @@
 // See the License for the specific language governing permissions
 // and limitations under the License.
 
-//go:build linux && amd64 && cgo
+//go:build linux && amd64 && cgo && rdma
 
 // Package rcroutes serves the /.hipobj-rc/{prepare,ready,cancel}
 // terminal routes of the hipobj-rc-v2 two-phase transfer protocol.
diff --git a/rdma/rcroutes/routes_stub.go b/rdma/rcroutes/routes_stub.go
index f3b5e03c..00fe86e5 100644
--- a/rdma/rcroutes/routes_stub.go
+++ b/rdma/rcroutes/routes_stub.go
@@ -11,7 +11,7 @@
 // See the License for the specific language governing permissions
 // and limitations under the License.
 
-//go:build !(linux && amd64 && cgo)
+//go:build !(linux && amd64 && cgo && rdma)
 
 // Package rcroutes serves the /.hipobj-rc control routes of the
 // hipobj-rc-v2 two-phase transfer protocol. This file is a stub
diff --git a/rdma/rcserver/rcserver_cgo_linux_test.go b/rdma/rcserver/rcserver_cgo_linux_test.go
index 7a0c3c52..033b5c14 100644
--- a/rdma/rcserver/rcserver_cgo_linux_test.go
+++ b/rdma/rcserver/rcserver_cgo_linux_test.go
@@ -13,7 +13,7 @@
 // specific language governing permissions and limitations
 // under the License.
 
-//go:build linux && cgo
+//go:build linux && amd64 && cgo && rdma
 
 package rcserver
 
diff --git a/rdma/rcserver/rcserver_linux.go b/rdma/rcserver/rcserver_linux.go
index aad73e0c..72d16c8e 100644
--- a/rdma/rcserver/rcserver_linux.go
+++ b/rdma/rcserver/rcserver_linux.go
@@ -11,7 +11,7 @@
 // See the License for the specific language governing permissions
 // and limitations under the License.
 
-//go:build linux && amd64 && cgo
+//go:build linux && amd64 && cgo && rdma
 
 // Package rcserver binds the RC session server (rdma/librcserver.a)
 // that implements the hipobj-rc-v2 two-phase transfer protocol.
diff --git a/rdma/rcserver/rcserver_stub.go b/rdma/rcserver/rcserver_stub.go
index 493e3b1a..ef546320 100644
--- a/rdma/rcserver/rcserver_stub.go
+++ b/rdma/rcserver/rcserver_stub.go
@@ -11,7 +11,7 @@
 // See the License for the specific language governing permissions
 // and limitations under the License.
 
-//go:build !(linux && amd64 && cgo)
+//go:build !(linux && amd64 && cgo && rdma)
 
 // Package rcserver binds the RC session server implementing the
 // hipobj-rc-v2 two-phase transfer protocol. This file is a stub for
diff --git a/rdma/rdma.go b/rdma/rdma.go
index 07187bf1..04e5de1b 100644
--- a/rdma/rdma.go
+++ b/rdma/rdma.go
@@ -12,7 +12,7 @@
 // specific language governing permissions and limitations
 // under the License.
 
-//go:build linux && amd64 && cgo
+//go:build linux && amd64 && cgo && rdma
 
 // Package rdma provides Go bindings to libcuobjserver via CGO.
 package rdma
diff --git a/rdma/rdma_stub.go b/rdma/rdma_stub.go
index 545622cb..336f8cae 100644
--- a/rdma/rdma_stub.go
+++ b/rdma/rdma_stub.go
@@ -12,7 +12,7 @@
 // specific language governing permissions and limitations
 // under the License.
 
-//go:build !(linux && amd64 && cgo)
+//go:build !(linux && amd64 && cgo && rdma)
 
 // Package rdma provides Go bindings to libcuobjserver.
 // This file is a stub for platforms without RDMA support.