feat: address-change redirects for writes outside the admin

- the RecordSaved listener re-describes an updated record of a content
  type after commit and applies AddressChanged per changed locale, so
  Journal's API, MCP and imports get the 301 too; an admin save that
  already applied it changes nothing more

listeners.go

@@ -3,14 +3,19 @@ package seo
 import (
 	"context"
 
+	"git.golem15.com/golem15/sm-seo-plugin/classes"
 	"git.golem15.com/golem15/summercms/modules/backpack"
 	"git.golem15.com/golem15/summercms/modules/pact"
+	"gorm.io/gorm"
 )
 
 // listen subscribes to the framework's record events (D-92): a deleted
-// record of a content type loses its SEO entries (kept in history), and a
-// created one gets its address snapshot. Listener errors are logged by the
-// bus and never fail the write that fired them.
+// record of a content type loses its SEO entries (kept in history), a
+// created one gets its address snapshot, and an updated one whose address
+// changed gets its 301 after commit (D-18), whoever wrote it: Journal's
+// API, MCP, an import, or an admin form whose SEO tab the administrator
+// does not see. Listener errors are logged by the bus and never fail the
+// write that fired them.
 func (p *Plugin) listen(app *backpack.App) {
 	if app == nil || app.Events == nil {
 		return
@@ -24,9 +29,43 @@ func (p *Plugin) listen(app *backpack.App) {
 	})
 	app.Events.Listen("golem15.seo", func(ctx context.Context, ev *pact.RecordSaved) error {
 		svc := p.Service()
-		if svc == nil || ev == nil || !ev.Created {
+		if svc == nil || ev == nil {
 			return nil
 		}
-		return svc.RecordCreated(ctx, ev)
+		if ev.Created {
+			return svc.RecordCreated(ctx, ev)
+		}
+		return p.addressesAfterSave(ctx, svc, ev.Model, ev.ID)
+	})
+}
+
+// addressesAfterSave re-describes a saved record of a content type in a
+// transaction of its own and applies AddressChanged to every locale whose
+// address differs from its entry's URL. After an admin save whose SEO tab
+// already did this, nothing differs and nothing happens.
+func (p *Plugin) addressesAfterSave(ctx context.Context, svc *classes.Service, model, id string) error {
+	reg := svc.Registry()
+	if reg == nil {
+		return nil
+	}
+	typ, ok := reg.ContentTypeForModel(model)
+	if !ok || typ.Content == nil {
+		return nil
+	}
+	db, err := svc.DB(ctx)
+	if err != nil {
+		return err
+	}
+	return db.Transaction(func(tx *gorm.DB) error {
+		changes, err := svc.AddressChanges(ctx, tx, typ, id)
+		if err != nil {
+			return err
+		}
+		for _, change := range changes {
+			if _, err := svc.AddressChanged(ctx, tx, change); err != nil {
+				return err
+			}
+		}
+		return nil
 	})
 }

redirects_test.go

@@ -2,6 +2,7 @@ package seo_test
 
 import (
 	"bytes"
+	"context"
 	"encoding/json"
 	"errors"
 	"net/http"
@@ -14,6 +15,9 @@ import (
 
 	"git.golem15.com/golem15/sm-seo-plugin/classes"
 	"git.golem15.com/golem15/sm-seo-plugin/models"
+	"git.golem15.com/golem15/summercms/modules/cabana"
+	"git.golem15.com/golem15/summercms/modules/lagoon"
+	"git.golem15.com/golem15/summercms/modules/pact"
 	"gorm.io/gorm"
 )
 
@@ -575,3 +579,68 @@ func TestNotFoundLog(t *testing.T) {
 		t.Fatalf("open filter = %v, want none", open)
 	}
 }
+
+// TestAddressChangeFromEvent checks the after-commit path for writes
+// outside the admin forms (D-18, D-92, D-102): a Journal-style write that
+// changes a published record's slug and fires RecordSaved without a
+// controller creates the 301; a save without an address change and a
+// change of an unpublished record create nothing.
+func TestAddressChangeFromEvent(t *testing.T) {
+	env := bootEnv(t)
+	token := env.admin(t, true)
+	id := env.createPage(t, token, map[string]any{"title": "Beta", "slug": "beta", "published": true})
+	draft := env.createPage(t, token, map[string]any{"title": "Draft", "slug": "draft", "published": false})
+
+	write := func(id string, changes ...pact.RecordChange) {
+		t.Helper()
+		if err := lagoon.Transaction(t.Context(), env.db, func(ctx context.Context, tx *gorm.DB) error {
+			for _, c := range changes {
+				if err := tx.Exec(`UPDATE acme_pages_pages SET `+c.Attribute+` = ? WHERE id = ?`, c.New, id).Error; err != nil {
+					return err
+				}
+			}
+			cabana.EmitRecordSaved(ctx, env.app, tx, pact.RecordSaved{Model: pagesModel, ID: id, Changes: changes})
+			return nil
+		}); err != nil {
+			t.Fatal(err)
+		}
+	}
+
+	write(id, pact.RecordChange{Attribute: "title", Old: "Beta", New: "Beta 2"})
+	if n := env.redirectCount(t); n != 0 {
+		t.Fatalf("redirects after a save without an address change = %d, want 0", n)
+	}
+
+	write(id, pact.RecordChange{Attribute: "slug", Old: "beta", New: "gamma"})
+	rows := env.redirects(t)
+	if redirectTo(rows, "/pages/beta") != "/pages/gamma" || redirectTo(rows, "/pl/pages/beta") != "/pl/pages/gamma" {
+		t.Fatalf("redirects after an API slug change = %+v, want /pages/beta -> /pages/gamma in both locales", rows)
+	}
+	for _, r := range rows {
+		if r.Origin != "slug" || r.Status != 301 {
+			t.Fatalf("redirect %+v, want a 301 with origin slug", r)
+		}
+	}
+	env.expectRedirect(t, "/pages/beta", 301, siteURL+"/pages/gamma")
+	if rows := env.revisions(t, "redirect"); len(rows) == 0 || rows[0].Via != "auto" {
+		t.Fatalf("redirect history = %+v, want via auto", rows)
+	}
+
+	before := env.redirectCount(t)
+	write(draft, pact.RecordChange{Attribute: "slug", Old: "draft", New: "draft-2"})
+	if n := env.redirectCount(t); n != before {
+		t.Fatalf("redirects after an unpublished record's slug change = %d, want %d", n, before)
+	}
+	var url string
+	if err := env.db.Raw(`SELECT url FROM golem15_seo_entries WHERE record_id = ? AND locale = 'en'`, draft).Scan(&url).Error; err != nil || url != "/pages/draft-2" {
+		t.Fatalf("unpublished entry URL = %q err=%v, want the new address without a redirect", url, err)
+	}
+
+	// An admin save already applied the change: the event after it
+	// changes nothing more.
+	env.expect(t, http.StatusOK, http.MethodPut, adminAPI("/acme/pages/pages/"+id), token, map[string]any{"title": "Beta 2", "slug": "delta", "published": true})
+	rows = env.redirects(t)
+	if redirectTo(rows, "/pages/gamma") != "/pages/delta" || redirectTo(rows, "/pages/beta") != "/pages/delta" {
+		t.Fatalf("redirects after the admin save = %+v, want both old addresses on /pages/delta", rows)
+	}
+}