Take the suffix of internal names from the Input and never the environment: Input.InternalSuffix and a local internal-name helper, so the package doc is true (review round 1, finding 5). The test failed first; the suite is 1257 tests in 1.04 s

go/compose/credentials_test.go

@@ -447,3 +447,25 @@ func TestAGivenFamilyMemberWithoutItsValueIsAStandInAndNamedForeseen(t *testing.
 		t.Errorf("foreseen %v", got.Foreseen)
 	}
 }
+
+// Round 1, finding 5: the suffix internal names end in is a field of the Input, and the environment is never read.
+func TestTheInternalSuffixIsTheInputsAndNeverTheEnvironments(t *testing.T) {
+	t.Setenv(overlay.SuffixVar, "from-the-environment")
+	in := aGrantMesh(t)
+	got := rendered(t, in, "anchor", Foreseeing)
+	if got.Rendering.Suffix != "internal" || got.Rendering.Grants[0].At != "laptop.internal" {
+		t.Errorf("by default: suffix %q, grant at %q", got.Rendering.Suffix, got.Rendering.Grants[0].At)
+	}
+	in.InternalSuffix = ".lan"
+	got = rendered(t, in, "anchor", Foreseeing)
+	if got.Rendering.Suffix != "lan" || got.Rendering.Grants[0].At != "laptop.lan" {
+		t.Errorf("given: suffix %q, grant at %q", got.Rendering.Suffix, got.Rendering.Grants[0].At)
+	}
+	where, err := newComposer(in).whereEveryoneIs()
+	if err != nil || where["anchor"] != "anchor.lan" {
+		t.Errorf("where everyone is: %v %v", where, err)
+	}
+	if names := newComposer(in).namesInTheMesh(); names["anchor.lan"] == "" || names["anchor.internal"] != "" {
+		t.Errorf("names: %v", names)
+	}
+}

go/compose/input.go

@@ -12,6 +12,7 @@
 // same refusals in the same words, so that a comparison node for node is a fair one.
 //
 // It imports the standard library and mesh-sdk's own packages only.
+// It reads no environment variable: the range the mesh allocates from and the suffix of its internal names are fields of Input.
 package compose
 
 import (
@@ -42,6 +43,9 @@ type Input struct {
 	// OverlayCIDR is the range the mesh allocates from when no tunnel was adopted, as genesis was told it (the
 	// controller's OverlayCIDRVar); empty means DefaultOverlayCIDR. The package reads no environment.
 	OverlayCIDR string
+	// InternalSuffix is what the mesh's internal names end in (the controller's MESH_INTERNAL_SUFFIX), with or without a leading
+	// dot; empty means overlay.DefaultSuffix. A fact of the whole mesh, so it is in the Input and never read from the environment.
+	InternalSuffix string
 	// Tunnels is, by node name, the found tunnel whose key is the node's overlay key (inv.Tunnels).
 	Tunnels map[string]FoundTunnel
 	// Adopted is the hub's found tunnel and the hub's name, whether or not the hub took it (inv.AdoptedTunnel); nil

go/compose/network.go

@@ -37,6 +37,19 @@ func (c *composer) say(format string, args ...any) {
 	c.said = append(c.said, line)
 }
 
+// suffix is what the mesh's internal names end in: the Input's, and overlay.DefaultSuffix when it gives none. The package never calls
+// overlay.Suffix or overlay.InternalName, which read the environment, so the assigner and the controller compose the same names
+// from the same Input.
+func (c *composer) suffix() string {
+	if v := strings.TrimPrefix(strings.TrimSpace(c.in.InternalSuffix), "."); v != "" {
+		return v
+	}
+	return overlay.DefaultSuffix
+}
+
+// internalName is a node's name inside the mesh.
+func (c *composer) internalName(node string) string { return node + "." + c.suffix() }
+
 // overlayRange is the range the mesh allocates node addresses from: the adopted tunnel's first (novox/hq ADR 0105),
 // then the range genesis was told, then the default.
 func (c *composer) overlayRange() string {
@@ -203,7 +216,7 @@ func (c *composer) whereEveryoneIs() (map[string]string, error) {
 	}
 	out := map[string]string{}
 	for _, p := range c.onTheNetwork() {
-		out[p.Name] = overlay.InternalName(p.Name)
+		out[p.Name] = c.internalName(p.Name)
 	}
 	return out, nil
 }

go/compose/rendering.go

@@ -120,7 +120,7 @@ func (c *composer) places(nodeName string, resolved Resolved) (Placed, error) {
 	// And who holds each replicated seat, where (novox/hq ADR 0223).
 	r.Holders = c.replicatedHolders()
 
-	r.Suffix, r.TunnelInterface = overlay.Suffix(), overlay.Interface
+	r.Suffix, r.TunnelInterface = c.suffix(), overlay.Interface
 
 	// And, for a module that keeps them, every operator-sealed secret in the mesh (novox/hq ADR 0085, amended).
 	for _, m := range plan.Modules {
@@ -272,16 +272,16 @@ func (c *composer) onThePrivateNetwork() []string {
 func (c *composer) namesInTheMesh() map[string]string {
 	out := map[string]string{}
 	for _, p := range c.onTheNetwork() {
-		out[overlay.InternalName(p.Name)] = p.Place.Address
+		out[c.internalName(p.Name)] = p.Place.Address
 	}
 	for _, p := range c.in.CarriedPeers {
 		if p.Named == "" || p.EnrolledAs != "" {
 			continue
 		}
-		if _, taken := out[overlay.InternalName(p.Named)]; taken {
+		if _, taken := out[c.internalName(p.Named)]; taken {
 			continue // a node of the mesh owns the name; the stale statement loses
 		}
-		out[overlay.InternalName(p.Named)] = p.Address
+		out[c.internalName(p.Named)] = p.Address
 	}
 	return out
 }
@@ -342,7 +342,7 @@ func (c *composer) artifactStoreAddress(forNode string) (string, error) {
 		return "", err
 	}
 	if found {
-		return overlay.InternalName(node) + ":" + port, nil
+		return c.internalName(node) + ":" + port, nil
 	}
 	all := map[string]bool{}
 	for _, n := range c.in.Nodes {
@@ -399,7 +399,7 @@ func (c *composer) zonesInTheMesh() ([]catalogue.ZoneAt, error) {
 			zones = append(zones, *z)
 		}
 	}
-	if problems := catalogue.ZonesProblems(zones, overlay.Suffix(), public); len(problems) > 0 {
+	if problems := catalogue.ZonesProblems(zones, c.suffix(), public); len(problems) > 0 {
 		return nil, fmt.Errorf("the mesh's zones cannot be forwarded:\n  - %s", strings.Join(problems, "\n  - "))
 	}
 	return zones, nil
@@ -458,7 +458,7 @@ func (c *composer) replicatedHolders() map[string]map[string]string {
 		at := map[string]string{}
 		for _, n := range nodes {
 			if address[n] != "" {
-				at[overlay.InternalName(n)] = address[n]
+				at[c.internalName(n)] = address[n]
 			}
 		}
 		out[seat.Name] = at