A-342 judge-node-env: a resource's own MESH_NODE is refused

The node-engine sets MESH_NODE to its node's name in every process it runs; the judge refuses a resource whose env sets it, so the mesh's value is the only one.

Builds: design 47 G A-342

Claude-Session: https://claude.ai/code/session_01NcbgfGKaxw984XyAPfLm4h

modules/mesh-delivery-indexer/judge/rules.go

@@ -2845,6 +2845,8 @@ func parseManifest(raw []byte, predefined catalogue.PredefinedList) (catalogue.M
 	// And the config values its resources are declared under (design 42 zfs-owns-zfs §2).
 	problems = append(problems, IfConfigProblems(m)...)
 	problems = append(problems, ConfigLinesProblems(m)...)
+	// And the node's name, which the node-engine sets in every process's env itself (design 47 G A-342).
+	problems = append(problems, NodeEnvProblems(m)...)
 	// And what it requires optionally, and the files it delivers only while bound (novox/hq ADR 0330).
 	problems = append(problems, OptionalProblems(m)...)
 	// And which setting keys each mergeable file takes (setting_takes.go, novox/hq ADR 0326).
@@ -4125,6 +4127,24 @@ func ProcessBusProblems(m catalogue.Manifest) []string {
 	return problems
 }
 
+// NodeEnv is the variable the node-engine sets to its node's name in the env of every process it runs (design 47 G
+// A-342): a resource's own value of it is refused, so the mesh's is the only one.
+const NodeEnv = "MESH_NODE"
+
+// NodeEnvProblems are the resources whose env sets NodeEnv themselves.
+func NodeEnvProblems(m catalogue.Manifest) []string {
+	var problems []string
+	for _, r := range m.Resources {
+		if env, ok := r["env"].(map[string]any); ok {
+			if _, sets := env[NodeEnv]; sets {
+				problems = append(problems, fmt.Sprintf("%s's resource %v sets %s in its env, which the node-engine sets to "+
+					"its node's name in every process it runs (design 47 G A-342)", m.Module, r["id"], NodeEnv))
+			}
+		}
+	}
+	return problems
+}
+
 func filepathDir(p string) string {
 	if i := strings.LastIndex(p, "/"); i > 0 {
 		return p[:i]

modules/mesh-delivery-indexer/judge/rules_test.go

@@ -2456,6 +2456,11 @@ func caseAProcessBusNamesOnlyTheModulesOwn(t *testing.T) {
 			t.Errorf("%s: %v; want a refusal naming %q", name, err, c.says)
 		}
 	}
+	// Design 47 G A-342: a resource setting the node's name in its own env is refused naming it.
+	ownNode := strings.Replace(mailSenderProcessManifest(t, ""), `"user":"mesh-mail-send"}`, `"user":"mesh-mail-send","env":{"MESH_NODE":"ace"}}`, 1)
+	if _, err := ParseManifest([]byte(ownNode)); err == nil || !strings.Contains(err.Error(), "MESH_NODE") {
+		t.Errorf("a process setting MESH_NODE itself: %v; want a refusal naming MESH_NODE", err)
+	}
 	// Design 47 G A-340: an event the module consumes, its process may hear.
 	consumed := strings.Replace(mailSenderProcessManifest(t, `{"consumes":["billing.paid"]}`), `"resources"`, `"consumes":["billing.paid"],"resources"`, 1)
 	if _, err := ParseManifest([]byte(consumed)); err != nil {