A Go tools bundle is served by its binary (hq ADR 0193)

A bundle compiled to a binary has no entrypoints, and loads had to name one, so a Go bundle could
not be served. Its binary is what the runtime starts: loads names the binary, derived when the
module lists tools, and the runtime is told the binary's path, delivered like any tools bundle.

internal/catalogue/build.go

@@ -87,6 +87,12 @@ func (m Manifest) Resolve(built []Built) (Manifest, error) {
 			loads := append([]string(nil), a.Loads...)
 			if a.Loads == nil && len(m.Tools) > 0 {
 				loads = append([]string(nil), a.Entrypoints...)
+				// A bundle compiled to a binary has no entrypoints: the binary is what it is, and what
+				// the runtime starts to serve it (novox/hq ADR 0193). So a Go tools bundle is served
+				// as Go — the runtime execs it — exactly as a TypeScript one is through its launcher.
+				if bin := BinaryOf(a); bin != "" {
+					loads = []string{bin}
+				}
 			}
 			// **Kept, never routed** (ADR 0155): the builder publishes to the store at the address
 			// it reached it by, and a manifest carrying that address names an installation —
@@ -242,6 +248,11 @@ func (b *Build) problems(module string) []string {
 				for _, e := range a.Entrypoints {
 					found = found || e == load
 				}
+				// A bundle compiled to a binary is one executable: the runtime loads that or nothing
+				// (novox/hq ADR 0193).
+				if bin := BinaryOf(a); bin != "" {
+					found = load == bin
+				}
 				if !found {
 					problems = append(problems, fmt.Sprintf(
 						"%s: %q says the runtime loads %q, which is not among its entrypoints — "+

internal/catalogue/runtime_test.go

@@ -389,3 +389,46 @@ func TestARuntimeCompiledToABinaryRunsItself(t *testing.T) {
 		t.Errorf("the Go runtime is not told what to serve or whose it is: %v %v", env, process["user"])
 	}
 }
+
+// novox/hq ADR 0193: a Go tools bundle is served — its binary is what the runtime starts, delivered
+// like any tools bundle, named to the runtime where a TypeScript bundle names its launcher.
+func TestAGoToolsBundleIsServedByItsBinary(t *testing.T) {
+	with := Rendering{ArtifactStore: "anchor.internal:5101",
+		Needed: map[string]map[string]string{RuntimeModule: {"broker": "sealed-credential"}}}
+	lamp := Manifest{Module: "lamp", Version: "1", Tools: []string{"on"},
+		Build: &Build{Artifacts: []Artifact{{Name: "tools", Kind: ArtifactBundle, Language: "go",
+			System: "arch", From: "cmd/lamp-tools"}}}}
+	if p := lamp.Build.problems("lamp"); len(p) != 0 {
+		t.Fatalf("a Go tools bundle was refused: %v", p)
+	}
+	lamp, err := lamp.Resolve([]Built{{Name: "tools", Kind: ArtifactBundle,
+		Reference: ArtifactStoreScheme + "lamp/tools/blobs/" + bundleDigest, Digest: bundleDigest}})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if fmt.Sprint(lamp.Bundles[0].Loads) != "[lamp-tools]" {
+		t.Fatalf("the runtime loads %v from a Go bundle, want its binary", lamp.Bundles[0].Loads)
+	}
+	out, err := Resolution{Node: "anchor", Account: "ops", Modules: []Manifest{lamp, theRuntime(t)}}.Declaration(with)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if fileNamed(out, "lamp."+BundleID("tools")) == nil {
+		t.Errorf("the Go bundle is not delivered: %v", ids(out))
+	}
+	env := fileNamed(out, RuntimeModule+"."+RuntimeProcessID())["env"].(map[string]string)
+	if env[RuntimeToolModules] != "lamp="+BundlePath("lamp", "tools")+"/lamp-tools" {
+		t.Errorf("the runtime is told %q, want the binary", env[RuntimeToolModules])
+	}
+
+	// An artifact may say it explicitly; naming anything but the binary is refused.
+	said := Manifest{Module: "lamp", Version: "1", Build: &Build{Artifacts: []Artifact{{Name: "tools",
+		Kind: ArtifactBundle, Language: "go", System: "arch", Binary: "lamp", Loads: []string{"lamp"}}}}}
+	if p := said.Build.problems("lamp"); len(p) != 0 {
+		t.Errorf("loads naming the binary was refused: %v", p)
+	}
+	said.Build.Artifacts[0].Loads = []string{"tools/index.js"}
+	if p := said.Build.problems("lamp"); len(p) == 0 {
+		t.Error("a Go bundle loading a file it does not contain was admitted")
+	}
+}