Hear a restricted stream only from a module's own account, never the tool runner's (issue 727)

The tool runner's bus account carried the heard grants, consumer and bind word of every module it runs, and every agent session on that machine reaches the bus as that account, so any session could pull a granted module's consumer on MAIL. Per ADR 0376 §1 the controller now composes a restricted stream's consumer, grants and bind word only for a module that declares runs-as; registration refuses a consumes of a restricted stream without runs-as (§2), and a grant that composes nothing is said in doctor (D-heard) and in the controller's log on every raise and send.

internal/catalogue/streams_test.go

@@ -204,3 +204,41 @@ func TestNarrowingTwoPatterns(t *testing.T) {
 		t.Fatalf("uncovered: %v", got)
 	}
 }
+
+// **A module that hears a restricted stream runs as an account of its own** (ADR 0376 §2): registration refuses a
+// `consumes` naming a module and asking for events its restricted stream carries, unless the manifest declares
+// `runs-as`; a stream without a grant, an event the provider says on EVENTS, and a wildcard emitter stay as they
+// were, and a consumer whose provider is not on the shelf is judged once it is.
+func TestHearingARestrictedStreamNeedsAnAccountOfItsOwn(t *testing.T) {
+	provider, err := ParseManifest([]byte(mailManifest(t, mailStream, `"emits":["account.added"],`)))
+	if err != nil {
+		t.Fatal(err)
+	}
+	feed := Manifest{Module: "feed", Streams: []StreamDeclaration{{Name: "items", Events: []string{"item.**"}}}}
+	carried := Manifest{Module: "reader", Consumes: []string{"mesh-mail.mail.*.message.added"}}
+	got := RestrictedHearingProblems(Shelf{"mesh-mail": provider, "reader": carried})
+	if len(got) != 1 || !strings.Contains(got[0], "reader consumes mesh-mail.mail.*.message.added") ||
+		!strings.Contains(got[0], "MAIL") || !strings.Contains(got[0], "runs-as") || !strings.Contains(got[0], "ADR 0376") {
+		t.Fatalf("a carried module hearing MAIL was not refused as it should be: %v", got)
+	}
+	if all := strings.Join(CatalogueProblems(Shelf{"mesh-mail": provider, "reader": carried}), "; "); !strings.Contains(all, got[0]) {
+		t.Fatalf("the catalogue's check does not refuse it: %s", all)
+	}
+	own := carried
+	own.RunsAs = "reader"
+	if got := RestrictedHearingProblems(Shelf{"mesh-mail": provider, "reader": own}); len(got) != 0 {
+		t.Fatalf("a module of its own account was refused: %v", got)
+	}
+	for _, m := range []Manifest{
+		{Module: "events", Consumes: []string{"mesh-mail.account.added"}},
+		{Module: "items", Consumes: []string{"feed.item.**"}},
+		{Module: "audit", Consumes: []string{"**", "*.mail.**"}},
+	} {
+		if got := RestrictedHearingProblems(Shelf{"mesh-mail": provider, "feed": feed, m.Module: m}); len(got) != 0 {
+			t.Errorf("%s was refused: %v", m.Module, got)
+		}
+	}
+	if got := RestrictedHearingProblems(Shelf{"reader": carried}); len(got) != 0 {
+		t.Fatalf("judged without its provider: %v", got)
+	}
+}