Delegate mixedbrain devserver lifecycle to Omes [blocked on OSS release]

Makefile

@@ -505,7 +505,7 @@ functional-with-fault-injection-test: clean-test-output
 
 mixed-brain-test: clean-test-output
 	@printf $(COLOR) "Run mixed brain tests..."
-	@CGO_ENABLED=1 TEST_OUTPUT_ROOT=$(CURDIR)/$(TEST_OUTPUT_ROOT) go test -v $(MIXED_BRAIN_TEST_ROOT) $(COMPILED_TEST_ARGS) 2>&1 | tee -a test.log
+	@cd $(MIXED_BRAIN_TEST_ROOT) && CGO_ENABLED=1 TEST_OUTPUT_ROOT=$(CURDIR)/$(TEST_OUTPUT_ROOT) go test -v ./... $(COMPILED_TEST_ARGS) 2>&1 | tee -a $(CURDIR)/test.log
 	@$(MAKE) verify-test-log
 
 verify-test-log:

tests/mixedbrain/.gitignore

@@ -0,0 +1,2 @@
+.devserver/
+.devserver.lock

tests/mixedbrain/build_util.go

@@ -17,41 +17,29 @@ import (
 
 const (
 	retryTimeout = 30 * time.Second
+	omesModule   = "github.com/temporalio/omes"
+	omesRepo     = "https://" + omesModule + ".git"
 	temporalRepo = "https://github.com/temporalio/temporal.git"
-	omesRepo     = "https://github.com/temporalio/omes"
-	omesCommit   = "8e4c1f54f3b0fb5e39d131f859c56fb2236395b1"
 )
 
 func sourceRoot() string {
 	_, filename, _, _ := runtime.Caller(0)
 	return filepath.Join(filepath.Dir(filename), "..", "..")
 }
 
-func cloneRepo(t *testing.T, url, destDir, ref string) {
+// omesRef returns the sha of github.com/temporalio/omes as pinned in go.mod,
+// queried via `go list -m` so go.mod stays the single source of truth.
+// Pseudo-versions look like "v0.0.0-20260512170720-ab5a6ff22874"; we take the
+// trailing 12-char sha.
+func omesRef(t *testing.T) string {
 	t.Helper()
-	t.Logf("Cloning %s at %s...", url, ref)
-	require.EventuallyWithT(t, func(collect *assert.CollectT) {
-		_ = os.RemoveAll(destDir)
-		out, err := exec.CommandContext(t.Context(), "git", "clone", "--filter=blob:none", url, destDir).CombinedOutput()
-		require.NoError(collect, err, "git clone failed:\n%s", out)
-	}, retryTimeout, 2*time.Second, "git clone "+filepath.Base(url))
-
-	out, err := exec.CommandContext(t.Context(), "git", "-C", destDir, "checkout", ref).CombinedOutput()
-	require.NoError(t, err, "git checkout %s failed:\n%s", ref, out)
-}
-
-func buildServer(t *testing.T, srcDir, outputPath string) {
-	t.Helper()
-	t.Logf("Building server binary from %s...", srcDir)
-	cmd := exec.CommandContext(t.Context(), "go",
-		"build",
-		"-tags", "disable_grpc_modules",
-		"-o", outputPath,
-		"./cmd/server",
-	)
-	cmd.Dir = srcDir
-	out, err := cmd.CombinedOutput()
-	require.NoError(t, err, "build server binary failed:\n%s", out)
+	out, err := exec.CommandContext(t.Context(), "go", "list", "-m", "-f", "{{.Version}}", omesModule).Output()
+	require.NoError(t, err, "go list -m %s", omesModule)
+	version := strings.TrimSpace(string(out))
+	if i := strings.LastIndex(version, "-"); i >= 0 {
+		return version[i+1:]
+	}
+	return version
 }
 
 // resolveReleaseVersion returns the highest version for the previous minor.
@@ -76,14 +64,10 @@ func resolveReleaseVersion(serverVersion string, tags []string) semver.Version {
 	return best
 }
 
-// downloadAndBuildReleaseServer finds the highest patch of the previous minor
-// version, clones the repo at that tag, and builds the server binary. For
-// example, if ServerVersion is 1.31.x, it will look for the highest 1.30.x
-// tag. Falls back to pre-release tags (cloud versions) if no stable release
-// exists yet.
-func downloadAndBuildReleaseServer(t *testing.T, outputPath string) string {
+// fetchPreviousMinorTag asks the temporal git remote for tags and resolves
+// the latest patch of the previous minor relative to headers.ServerVersion.
+func fetchPreviousMinorTag(t *testing.T) string {
 	t.Helper()
-
 	t.Log("Resolving release tags...")
 	var version semver.Version
 	require.EventuallyWithT(t, func(collect *assert.CollectT) {
@@ -101,30 +85,31 @@ func downloadAndBuildReleaseServer(t *testing.T, outputPath string) string {
 		version = resolveReleaseVersion(headers.ServerVersion, tags)
 		require.NotEqual(collect, semver.Version{}, version, "no tags found for previous minor")
 	}, retryTimeout, 2*time.Second, "fetch release tags")
-
-	tag := "v" + version.String()
-	repoDir := filepath.Join(filepath.Dir(outputPath), "temporal-release")
-	cloneRepo(t, temporalRepo, repoDir, tag)
-
-	t.Log("Building release server binary...")
-	buildServer(t, repoDir, outputPath)
-	return tag
+	return "v" + version.String()
 }
 
-func downloadAndBuildOmes(t *testing.T, workDir string) {
+// downloadAndBuildOmes clones omes at omesRef into workDir/omes and builds its
+// CLI into outputPath. We clone instead of going through the module cache so
+// the build resolves omes's transitive deps independently of this module's
+// go.sum (omes uses replace directives that block `go install`).
+func downloadAndBuildOmes(t *testing.T, workDir, outputPath string) {
 	t.Helper()
 
 	repoDir := filepath.Join(workDir, "omes")
-	cloneRepo(t, omesRepo, repoDir, omesCommit)
+	ref := omesRef(t)
+	t.Logf("Cloning %s at %s...", omesRepo, ref)
+	require.EventuallyWithT(t, func(collect *assert.CollectT) {
+		_ = os.RemoveAll(repoDir)
+		out, err := exec.CommandContext(t.Context(), "git", "clone", "--filter=blob:none", omesRepo, repoDir).CombinedOutput()
+		require.NoError(collect, err, "git clone failed:\n%s", out)
+	}, retryTimeout, 2*time.Second, "git clone omes")
+
+	out, err := exec.CommandContext(t.Context(), "git", "-C", repoDir, "checkout", ref).CombinedOutput()
+	require.NoError(t, err, "git checkout %s failed:\n%s", ref, out)
 
-	t.Log("Building Omes...")
-	omesBinary := filepath.Join(workDir, "omes-bin")
-	buildCmd := exec.CommandContext(t.Context(), "go",
-		"build",
-		"-o", omesBinary,
-		"./cmd",
-	)
-	buildCmd.Dir = repoDir
-	out, err := buildCmd.CombinedOutput()
-	require.NoError(t, err, "build Omes failed:\n%s", out)
+	t.Logf("Building omes into %s...", outputPath)
+	cmd := exec.CommandContext(t.Context(), "go", "build", "-o", outputPath, "./cmd")
+	cmd.Dir = repoDir
+	out, err = cmd.CombinedOutput()
+	require.NoError(t, err, "build omes failed:\n%s", out)
 }

tests/mixedbrain/go.mod

@@ -0,0 +1,33 @@
+module go.temporal.io/server/tests/mixedbrain
+
+go 1.26.3
+
+require (
+	github.com/blang/semver/v4 v4.0.0
+	github.com/stretchr/testify v1.11.1
+	github.com/temporalio/omes v0.0.0-20260528212322-14460bcc246f
+	go.temporal.io/api v1.62.13-0.20260522153111-260c04482807
+	go.temporal.io/server v0.0.0-00010101000000-000000000000
+	go.uber.org/zap v1.27.1
+	google.golang.org/grpc v1.80.0
+	google.golang.org/protobuf v1.36.11
+)
+
+require (
+	github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc // indirect
+	github.com/gofrs/flock v0.13.0 // indirect
+	github.com/grpc-ecosystem/grpc-gateway/v2 v2.29.0 // indirect
+	github.com/nexus-rpc/nexus-proto-annotations v0.1.0 // indirect
+	github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2 // indirect
+	go.uber.org/multierr v1.11.0 // indirect
+	golang.org/x/net v0.53.0 // indirect
+	golang.org/x/sys v0.43.0 // indirect
+	golang.org/x/text v0.36.0 // indirect
+	google.golang.org/genproto/googleapis/api v0.0.0-20260420184626-e10c466a9529 // indirect
+	google.golang.org/genproto/googleapis/rpc v0.0.0-20260420184626-e10c466a9529 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
+)
+
+replace go.temporal.io/server => ../..
+
+replace go.temporal.io/sdk => go.temporal.io/sdk v1.42.0