Disable zones instead of deleting them

A disabled zone stays in Jarl with its records, options and history,
still editable, but named doesn't load it; enabling it serves it as it is
then. Signed zones, and zones another view shares, can't be disabled.
jarl zone disable|enable, the zone page's Disable/Enable button.
Database schema 7.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

internal/engine/zonedisable_test.go

@@ -0,0 +1,81 @@
+package engine
+
+import (
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"jarl/internal/model"
+)
+
+func TestZoneDisable(t *testing.T) {
+	env := newEnv(t)
+	setupZone(env)
+	z := env.state().ZonesNamed("example.com")[0]
+	confPath := filepath.Join(env.dir, "etc/named.conf")
+	zonePath := filepath.Join(env.dir, "zones/_default/example.com.zone")
+
+	res := env.submit(env.admin, NewRequest(OpZoneUpdate, z.ID, ZoneInput{Disabled: model.Ptr(true)}))
+	if res.Ops[0].Summary != "disable zone example.com" || len(res.Warnings) != 1 || !strings.Contains(res.Warnings[0], "recursion") {
+		t.Errorf("disable: %q, warnings %v", res.Ops[0].Summary, res.Warnings)
+	}
+	conf, _ := os.ReadFile(confPath)
+	if strings.Contains(string(conf), "zone \"example.com\" {") || !strings.Contains(string(conf), `// zone "example.com" is disabled in Jarl`) {
+		t.Errorf("named.conf with the zone disabled:\n%s", conf)
+	}
+	// Still edited, and its file kept up to date.
+	env.submit(env.admin, rec("example.com", "www", "A", "192.0.2.10"))
+	if f, err := os.ReadFile(zonePath); err != nil || !strings.Contains(string(f), "www\t\tIN\tA\t192.0.2.10") {
+		t.Errorf("zone file while disabled: %v\n%s", err, f)
+	}
+
+	// Enabling brings it back.
+	res = env.submit(env.admin, NewRequest(OpZoneUpdate, z.ID, ZoneInput{Disabled: model.Ptr(false)}))
+	if res.Ops[0].Summary != "enable zone example.com" {
+		t.Errorf("enable: %q", res.Ops[0].Summary)
+	}
+	if conf, _ := os.ReadFile(confPath); !strings.Contains(string(conf), "zone \"example.com\" {") {
+		t.Errorf("named.conf after enabling:\n%s", conf)
+	}
+	// Reverting a disable enables the zone again.
+	res = env.submit(env.admin, NewRequest(OpZoneUpdate, z.ID, ZoneInput{Disabled: model.Ptr(true)}))
+	rev, err := env.e.Revert(env.ctx, res.ChangesetID, env.admin)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if _, err := env.e.Apply(env.ctx, rev.ID, env.admin, ApplyOptions{}); err != nil || env.state().Zones[z.ID].Disabled {
+		t.Errorf("revert of a disable: %v, disabled=%v", err, env.state().Zones[z.ID].Disabled)
+	}
+
+	// Signed zones can't be disabled.
+	env.submit(env.admin, NewRequest(OpZoneUpdate, z.ID, ZoneInput{DNSSECPolicy: model.Ptr("default")}))
+	if e := env.submitErr(env.admin, NewRequest(OpZoneUpdate, z.ID, ZoneInput{Disabled: model.Ptr(true)})); e.Kind != KindValidation || !strings.Contains(e.Message, "signed zone can't be disabled") {
+		t.Errorf("disabling a signed zone: %+v", e)
+	}
+}
+
+func TestZoneDisableInView(t *testing.T) {
+	env := newEnv(t)
+	setupZone(env)
+	env.submit(env.admin,
+		NewRequest(OpViewCreate, 0, ViewInput{Name: model.Ptr("internal"), MatchClients: &[]string{"10.0.0.0/8"}, AdoptZones: true}),
+		NewRequest(OpViewCreate, 0, ViewInput{Name: model.Ptr("external")}),
+	)
+	st := env.state()
+	ext := st.ViewByName("external")
+	env.submit(env.admin, NewRequest(OpZoneCreate, 0, ZoneInput{Name: model.Ptr("example.com"), ViewID: &ext.ID, Type: model.Ptr(model.ZoneInView), InView: model.Ptr("internal")}))
+	in := st.ZonesNamed("example.com")[0]
+	// The zone another view shares can't be disabled alone.
+	if e := env.submitErr(env.admin, NewRequest(OpZoneUpdate, in.ID, ZoneInput{Disabled: model.Ptr(true)})); e.Kind != KindValidation || !strings.Contains(e.Message, "is disabled, so this zone can't share it") {
+		t.Errorf("disabling a shared zone: %+v", e)
+	}
+	// Without recursion, the warning says REFUSED.
+	env.submit(env.admin, NewRequest(OpOptionCreate, 0, OptionInput{Scope: model.Ptr(model.ScopeView), ScopeID: &ext.ID, Name: model.Ptr("recursion"), Value: model.Ptr("no")}))
+	env.submit(env.admin, NewRequest(OpZoneCreate, 0, ZoneInput{Name: model.Ptr("public.example"), ViewID: &ext.ID}))
+	pub := env.state().FindZone("public.example", ext.ID)
+	res := env.submit(env.admin, NewRequest(OpZoneUpdate, pub.ID, ZoneInput{Disabled: model.Ptr(true)}))
+	if len(res.Warnings) != 1 || !strings.Contains(res.Warnings[0], "view external answers REFUSED") {
+		t.Errorf("warnings = %v", res.Warnings)
+	}
+}