Stop bumping cookie banner version on no-op updates

A central snapshot-equality guard in ensureDraftVersion now returns
the latest version unchanged when the candidate snapshot matches it,
so no-op admin saves no longer force visitors to re-consent. Per-
operation short-circuits in UpdateCookieBanner, UpdateCookieCategory,
UpdateCookiePattern, DeleteCookiePattern, MoveCookiePatternToCategory,
ReorderCookieCategory, and UpsertCookieBannerTranslation skip the row
update and version bump when nothing visitor-facing changes (excluded
patterns, identical values, identical translation JSON).

Rank is now treated as admin-only metadata: buildSnapshot sorts
categories by (Kind weight, ID byte order) instead of relying on the
implicit rank-driven slice order, and ReorderCookieCategory no longer
calls ensureDraftVersionForBanner. Default banners keep their
visitor-facing order (insertion order matches Kind+ID); banners with
admin-customised ranks see a one-time order shift to insertion order
on the next snapshot rebuild.

Reusable equality helpers (Ptr generic + JSON canonicalisation) move
to a new pkg/equal package; snapshotsEqual stays in service.go as the
documented chokepoint for visitor-identical snapshot comparison.

Signed-off-by: Émile Ré <emile@getprobo.com>

pkg/equal/equal.go

@@ -0,0 +1,48 @@
+// Copyright (c) 2026 Probo Inc <hello@getprobo.com>.
+//
+// Permission to use, copy, modify, and/or distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice appear in all copies.
+//
+// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
+// REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+// AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
+// INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+// LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
+// OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+// PERFORMANCE OF THIS SOFTWARE.
+
+// Package equal contains small helpers for value equality across the
+// codebase, with no business semantics.
+package equal
+
+import (
+	"encoding/json"
+	"fmt"
+	"reflect"
+)
+
+// Ptr reports whether two nullable values are equal: both nil are equal,
+// one nil is not equal to a non-nil, otherwise the pointed-to values are
+// compared with ==.
+func Ptr[T comparable](a, b *T) bool {
+	if a == nil || b == nil {
+		return a == b
+	}
+	return *a == *b
+}
+
+// JSON reports whether two JSON blobs are semantically identical after
+// normalising whitespace and (top-level and nested) object key ordering.
+// Array element order is preserved as significant. Numbers are compared
+// after JSON unmarshalling, so 1 and 1.0 compare equal.
+func JSON(a, b json.RawMessage) (bool, error) {
+	var av, bv any
+	if err := json.Unmarshal(a, &av); err != nil {
+		return false, fmt.Errorf("cannot unmarshal first json blob: %w", err)
+	}
+	if err := json.Unmarshal(b, &bv); err != nil {
+		return false, fmt.Errorf("cannot unmarshal second json blob: %w", err)
+	}
+	return reflect.DeepEqual(av, bv), nil
+}

pkg/equal/equal_test.go

@@ -0,0 +1,147 @@
+// Copyright (c) 2026 Probo Inc <hello@getprobo.com>.
+//
+// Permission to use, copy, modify, and/or distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice appear in all copies.
+//
+// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
+// REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+// AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
+// INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+// LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
+// OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+// PERFORMANCE OF THIS SOFTWARE.
+
+package equal_test
+
+import (
+	"encoding/json"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"go.probo.inc/probo/pkg/equal"
+)
+
+func TestPtr_String(t *testing.T) {
+	t.Parallel()
+
+	a := "hello"
+	b := "hello"
+	c := "world"
+
+	assert.True(t, equal.Ptr[string](nil, nil))
+	assert.False(t, equal.Ptr(&a, nil))
+	assert.False(t, equal.Ptr[string](nil, &a))
+	assert.True(t, equal.Ptr(&a, &b))
+	assert.False(t, equal.Ptr(&a, &c))
+}
+
+func TestPtr_Int(t *testing.T) {
+	t.Parallel()
+
+	a := 42
+	b := 42
+	c := 99
+
+	assert.True(t, equal.Ptr[int](nil, nil))
+	assert.False(t, equal.Ptr(&a, nil))
+	assert.False(t, equal.Ptr[int](nil, &a))
+	assert.True(t, equal.Ptr(&a, &b))
+	assert.False(t, equal.Ptr(&a, &c))
+}
+
+func TestPtr_Bool(t *testing.T) {
+	t.Parallel()
+
+	tt := true
+	tt2 := true
+	ff := false
+
+	assert.True(t, equal.Ptr(&tt, &tt2))
+	assert.False(t, equal.Ptr(&tt, &ff))
+}
+
+func TestJSON(t *testing.T) {
+	t.Parallel()
+
+	t.Run("identical bytes", func(t *testing.T) {
+		t.Parallel()
+
+		a := json.RawMessage(`{"foo":"bar","n":1}`)
+		b := json.RawMessage(`{"foo":"bar","n":1}`)
+
+		eq, err := equal.JSON(a, b)
+		require.NoError(t, err)
+		assert.True(t, eq)
+	})
+
+	t.Run("whitespace and key order differences", func(t *testing.T) {
+		t.Parallel()
+
+		a := json.RawMessage(`{"foo":"bar","n":1}`)
+		b := json.RawMessage("{\n  \"n\": 1,\n  \"foo\": \"bar\"\n}")
+
+		eq, err := equal.JSON(a, b)
+		require.NoError(t, err)
+		assert.True(t, eq)
+	})
+
+	t.Run("nested objects with reordered keys", func(t *testing.T) {
+		t.Parallel()
+
+		a := json.RawMessage(`{"a":{"x":1,"y":2},"b":[1,2,3]}`)
+		b := json.RawMessage(`{"b":[1,2,3],"a":{"y":2,"x":1}}`)
+
+		eq, err := equal.JSON(a, b)
+		require.NoError(t, err)
+		assert.True(t, eq)
+	})
+
+	t.Run("array order matters", func(t *testing.T) {
+		t.Parallel()
+
+		a := json.RawMessage(`{"items":[1,2,3]}`)
+		b := json.RawMessage(`{"items":[3,2,1]}`)
+
+		eq, err := equal.JSON(a, b)
+		require.NoError(t, err)
+		assert.False(t, eq)
+	})
+
+	t.Run("real content change", func(t *testing.T) {
+		t.Parallel()
+
+		a := json.RawMessage(`{"title":"Cookies"}`)
+		b := json.RawMessage(`{"title":"Cookies updated"}`)
+
+		eq, err := equal.JSON(a, b)
+		require.NoError(t, err)
+		assert.False(t, eq)
+	})
+
+	t.Run("integers and floats compare equal", func(t *testing.T) {
+		t.Parallel()
+
+		a := json.RawMessage(`{"n":1}`)
+		b := json.RawMessage(`{"n":1.0}`)
+
+		eq, err := equal.JSON(a, b)
+		require.NoError(t, err)
+		assert.True(t, eq, "json.Unmarshal yields float64 for both")
+	})
+
+	t.Run("invalid first blob returns error", func(t *testing.T) {
+		t.Parallel()
+
+		_, err := equal.JSON(json.RawMessage(`not json`), json.RawMessage(`{}`))
+		assert.Error(t, err)
+	})
+
+	t.Run("invalid second blob returns error", func(t *testing.T) {
+		t.Parallel()
+
+		_, err := equal.JSON(json.RawMessage(`{}`), json.RawMessage(`not json`))
+		assert.Error(t, err)
+	})
+}