Give the build verb the command's other two shapes, so a changed base or a source that moved can be rebuilt through the console

The verb took only a repository; build --on <module> and build --behind were reachable only through the generic command verb. Each shape is one per call, and a second beside it is refused as passed over.

internal/catalogue/verbs.go

@@ -396,13 +396,22 @@ var ControllerVerbs = []Verb{
 			"machine": "one machine (optional)",
 			"retired": "\"true\": only what is retired",
 		}, nil, "retired")},
-	{Name: "build", Description: "Have the build machine build a repository. Answers at once with the build's id: " +
-		"`builds` with that id follows it line by line, and the module is registered when the outcome comes.",
+	// Three shapes, as the command has them: one repository, every module standing on a base (on), or
+	// every module behind its source (behind). One per call; a second is refused as passed over.
+	{Name: "build", Description: "Have the build machine build a repository — or, instead, every module that " +
+		"stands on a base (on), or every module behind its source (behind). Answers at once with each build's id: " +
+		"`builds` with an id follows it line by line, and a module is registered when its outcome comes.",
 		Input: schema(map[string]string{
-			"repository": "the repository's URL, or its path on the forge holding the git seat (owner/name)",
-			"path":       "the module's directory inside it (optional)",
-			"ref":        "the branch, tag or commit to build (optional)",
-		}, []string{"repository"})},
+			"repository": "the repository's URL, or its path on the forge holding the git seat (owner/name); " +
+				"needed unless on or behind is given",
+			"path": "with repository: the module's directory inside it (optional)",
+			"ref":  "with repository: the branch, tag or commit to build (optional)",
+			"on": "instead of a repository: a module's name. Every module the mesh holds that was built against " +
+				"its artifacts is built again from its own source, bases among them asked first — the rebuild a " +
+				"changed base needs, which behind does not see because their sources did not move",
+			"behind": "\"true\", instead of a repository: build every module the mesh holds whose source has moved " +
+				"past the commit it was built from, bases asked first",
+		}, nil, "behind")},
 }
 
 // schema is a JSON schema for an object of string properties, which is every argument the verbs

internal/inventory/seats_test.go

@@ -227,3 +227,48 @@ func TestASeatsVerbGainsTheArgumentsTheBinaryNames(t *testing.T) {
 		}
 	}
 }
+
+// **A stored row's build verb takes on and behind** (novox/hq ADR 0246: arguments added to a verb are
+// additive): a row seeded before them described build with a repository it required, so the console
+// would refuse both and a call naming neither would be refused for want of a repository. Re-seeding
+// gives the row this binary's build.
+func TestAStoredRowsBuildVerbTakesOnAndBehind(t *testing.T) {
+	inv := ForTest(t)
+	ctx := t.Context()
+	if _, err := inv.SeedSeats(ctx, catalogue.DefaultSeats()); err != nil {
+		t.Fatal(err)
+	}
+	old := `[{"name":"build","description":"Have the build machine build a repository.","input":{"type":"object",
+	          "properties":{"repository":{"type":"string"},"path":{"type":"string"},"ref":{"type":"string"}},
+	          "required":["repository"]}}]`
+	if _, err := inv.store.Pool().Exec(ctx, `update seat set serves = $1 where name = $2`,
+		[]byte(old), catalogue.ControllerSeatName); err != nil {
+		t.Fatal(err)
+	}
+	if _, err := inv.SeedSeats(ctx, catalogue.DefaultSeats()); err != nil {
+		t.Fatal(err)
+	}
+	seats, err := inv.Seats(ctx)
+	if err != nil {
+		t.Fatal(err)
+	}
+	var build catalogue.Verb
+	for _, s := range seats {
+		if s.Name == catalogue.ControllerSeatName {
+			for _, v := range s.Serves {
+				if v.Name == "build" {
+					build = v
+				}
+			}
+		}
+	}
+	props, _ := build.Input["properties"].(map[string]any)
+	for _, arg := range []string{"repository", "path", "ref", "on", "behind"} {
+		if _, has := props[arg]; !has {
+			t.Errorf("build in the row does not take %s: %v", arg, props)
+		}
+	}
+	if req, _ := build.Input["required"].([]any); len(req) != 0 {
+		t.Errorf("build in the row still requires %v, so on and behind alone are refused", req)
+	}
+}