feat(backend)!: run on Postgres with a migration-owned schema (#28)

Swap modernc.org/sqlite for jackc/pgx/v5 with no observable change:
same endpoints, same wire format, same updated_at ordering rule.

The schema now comes from numbered SQL embedded in the binary and
applied on startup, one transaction each, recorded in
schema_migrations. That replaces two pieces of SQLite-era machinery,
both deleted rather than ported: the column probing (Postgres has ADD
COLUMN IF NOT EXISTS, and there is no legacy database left to probe)
and the Asura key rewrite, which has run clean on every start for
months now that the userscripts strip build hashes before writing. Its
regexp survives as latest.asuraBuildHash, where the poller still needs
it to scope chapter links to a series whose slug carries a rotating
hash.

Types get real: favorite is a boolean, chapter numbers double
precision, timestamps stay unix-ms bigint. SQLite's null-safe IS NOT
becomes IS DISTINCT FROM, which is what implements the rule that only
reading progress reorders a list. Inside COALESCE/NULLIF the status
and kind parameters need an explicit ::text -- there is no target
column to infer from and Postgres refuses to guess.

Tests lose their free t.TempDir() database, so Docker is now a hard
prerequisite for `go test ./...`: internal/pgtest starts one
postgres:17-alpine per test binary and hands each test a database of
its own.

Also lands CONTEXT.md and the four ADRs written while scoping #18.

BREAKING CHANGE: DB_PATH is retired for DATABASE_URL, which is
required and has no default. Compose gains a postgres service on an
internal network with its own volume; POSTGRES_PASSWORD joins .env.
The old bookmarks-data volume is deliberately left undeclared so
`docker compose down -v` cannot take the pre-migration database with
it. main is not deployable until #25 and #26 land.

Closes #20

Co-authored-by: Sulthan Zaki <sultankiki05@gmail.com>
Co-committed-by: Sulthan Zaki <sultankiki05@gmail.com>

backend/internal/store/migrations/0001_bookmarks.sql

@@ -0,0 +1,28 @@
+-- One row per tracked series, keyed "<site>:<series_id>".
+--
+-- Everything is NOT NULL with a default except latest_chapter_num, where NULL
+-- is a distinct state: nothing has been captured yet, which is not the same as
+-- chapter zero.
+--
+-- Timestamps are unix milliseconds as bigint, not timestamptz: the userscripts
+-- send Date.now() over the wire and the ordering rule compares them directly.
+CREATE TABLE bookmarks (
+  key                text PRIMARY KEY,
+  site               text NOT NULL,
+  series_id          text NOT NULL,
+  title              text NOT NULL DEFAULT '',
+  series_url         text NOT NULL DEFAULT '',
+  cover              text NOT NULL DEFAULT '',
+  last_chapter       text NOT NULL DEFAULT '',
+  last_chapter_num   double precision NOT NULL DEFAULT 0,
+  last_chapter_url   text NOT NULL DEFAULT '',
+  favorite           boolean NOT NULL DEFAULT false,
+  latest_chapter     text NOT NULL DEFAULT '',
+  latest_chapter_num double precision,
+  -- When the server last polled this series, unix ms; 0 means never, and sorts
+  -- first so a new bookmark is picked up on the next tick with no special case.
+  latest_checked_at  bigint NOT NULL DEFAULT 0,
+  status             text NOT NULL DEFAULT 'reading',
+  kind               text NOT NULL DEFAULT 'manga',
+  updated_at         bigint NOT NULL
+);

backend/internal/store/store.go

@@ -2,13 +2,17 @@ package store
 
 import (
 	"database/sql"
+	"embed"
 	"errors"
 	"fmt"
+	"io/fs"
+	"path"
 	"regexp"
+	"slices"
 	"strconv"
 	"strings"
 
-	_ "modernc.org/sqlite"
+	_ "github.com/jackc/pgx/v5/stdlib"
 )
 
 // Bookmark is one tracked series, keyed "<site>:<series_id>" across both sites.
@@ -114,222 +118,119 @@ const (
 	StatusFinished = "finished"
 )
 
-const schema = `
-CREATE TABLE IF NOT EXISTS bookmarks (
-  key                TEXT PRIMARY KEY,
-  site               TEXT NOT NULL,
-  series_id          TEXT NOT NULL,
-  title              TEXT,
-  series_url         TEXT,
-  cover              TEXT,
-  last_chapter       TEXT,
-  last_chapter_num   REAL,
-  last_chapter_url   TEXT,
-  favorite           INTEGER NOT NULL DEFAULT 0,
-  latest_chapter     TEXT NOT NULL DEFAULT '',
-  latest_chapter_num REAL,
-  latest_checked_at  INTEGER NOT NULL DEFAULT 0,
-  status             TEXT NOT NULL DEFAULT 'reading',
-  kind               TEXT NOT NULL DEFAULT 'manga',
-  updated_at         INTEGER NOT NULL
-);`
-
-// The columns above that databases created before them will be missing.
-// SQLite has no ADD COLUMN IF NOT EXISTS, so each is added only when absent.
-var addedColumns = []struct{ name, ddl string }{
-	{"favorite", `ALTER TABLE bookmarks ADD COLUMN favorite INTEGER NOT NULL DEFAULT 0`},
-	{"latest_chapter", `ALTER TABLE bookmarks ADD COLUMN latest_chapter TEXT NOT NULL DEFAULT ''`},
-	{"latest_chapter_num", `ALTER TABLE bookmarks ADD COLUMN latest_chapter_num REAL`},
-	// When the server last looked at this series, unix ms; 0 means never, and
-	// sorts first so a new bookmark is picked up on the next tick with no
-	// special case. Deliberately NOT in bookmarkColumns — see MarkLatestChecked.
-	{"latest_checked_at", `ALTER TABLE bookmarks ADD COLUMN latest_checked_at INTEGER NOT NULL DEFAULT 0`},
-	// Lifecycle bucket. The DEFAULT backfills every pre-existing row as
-	// 'reading', so there is no separate migration step.
-	{"status", `ALTER TABLE bookmarks ADD COLUMN status TEXT NOT NULL DEFAULT 'reading'`},
-	// Library bucket. The DEFAULT backfills every pre-existing row as 'manga',
-	// which is what every row written before novels existed actually is.
-	{"kind", `ALTER TABLE bookmarks ADD COLUMN kind TEXT NOT NULL DEFAULT 'manga'`},
-}
+//go:embed migrations/*.sql
+var migrations embed.FS
 
+// bookmarkColumns is the only value ever concatenated into query text. It is a
+// compile-time constant; every request value is bound as a parameter.
 const bookmarkColumns = `key, site, series_id, title, series_url, cover,
 	last_chapter, last_chapter_num, last_chapter_url,
 	favorite, latest_chapter, latest_chapter_num, updated_at, status, kind`
 
-// Store is the SQLite-backed bookmark store.
+// Store is the Postgres-backed bookmark store.
 type Store struct {
 	db *sql.DB
 }
 
-// OpenStore opens (or creates) the SQLite database at path and applies the schema.
-func Open(path string) (*Store, error) {
-	// busy_timeout guards against SQLITE_BUSY under the reverse proxy's
-	// concurrent requests; a single writer connection keeps writes serialized.
-	dsn := path
-	if !strings.Contains(dsn, "?") {
-		dsn += "?_pragma=busy_timeout(5000)&_pragma=journal_mode(WAL)"
-	}
-	db, err := sql.Open("sqlite", dsn)
+// Open connects to Postgres at url — a libpq connection URL such as
+// "postgres://user:pass@host:5432/bookmarks?sslmode=disable" — and brings its
+// schema up to date.
+func Open(url string) (*Store, error) {
+	db, err := sql.Open("pgx", url)
 	if err != nil {
-		return nil, fmt.Errorf("open sqlite %q: %w", path, err)
+		return nil, fmt.Errorf("open postgres: %w", err)
 	}
-	db.SetMaxOpenConns(1)
-	if _, err := db.Exec(schema); err != nil {
+	if err := migrate(db); err != nil {
 		db.Close()
-		return nil, fmt.Errorf("apply schema: %w", err)
-	}
-	if err := migrateColumns(db); err != nil {
-		db.Close()
-		return nil, fmt.Errorf("migrate schema: %w", err)
-	}
-	if err := migrateAsuraKeys(db); err != nil {
-		db.Close()
-		return nil, fmt.Errorf("migrate asura keys: %w", err)
+		return nil, fmt.Errorf("migrate: %w", err)
 	}
 	return &Store{db: db}, nil
 }
 
-// migrateColumns brings a pre-existing bookmarks table up to the current
-// schema. Safe to run on every start: columns already present are skipped.
-func migrateColumns(db *sql.DB) error {
-	have, err := existingColumns(db, "bookmarks")
+// migrate applies every embedded migration this database has not recorded, in
+// filename order, each in its own transaction. Files are named
+// "<version>_<name>.sql" and are append-only: editing an applied file changes
+// nothing, because schema_migrations is how a database remembers what it ran.
+// Runs on every start and is a no-op once current.
+func migrate(db *sql.DB) error {
+	if _, err := db.Exec(`CREATE TABLE IF NOT EXISTS schema_migrations (
+		version    bigint PRIMARY KEY,
+		applied_at timestamptz NOT NULL DEFAULT now())`); err != nil {
+		return fmt.Errorf("create version table: %w", err)
+	}
+
+	names, err := fs.Glob(migrations, "migrations/*.sql")
 	if err != nil {
 		return err
 	}
-	for _, c := range addedColumns {
-		if _, ok := have[c.name]; ok {
-			continue
+	slices.Sort(names)
+
+	for _, name := range names {
+		version, err := strconv.ParseInt(strings.SplitN(path.Base(name), "_", 2)[0], 10, 64)
+		if err != nil {
+			return fmt.Errorf("migration %q: filename must start with a version number", name)
 		}
-		if _, err := db.Exec(c.ddl); err != nil {
-			return fmt.Errorf("add column %q: %w", c.name, err)
+		body, err := migrations.ReadFile(name)
+		if err != nil {
+			return err
+		}
+		if err := applyMigration(db, version, string(body)); err != nil {
+			return fmt.Errorf("migration %q: %w", name, err)
 		}
 	}
 	return nil
 }
 
-// AsuraBuildHash matches the trailing "-xxxxxxxx" site-wide build ID Asura
-// appends to every series slug. It rotates on each site redeploy, so it
-// must not be part of series_id. Must stay in sync with stripBuildHash in
-// userscript/manga-bookmark.user.js.
-var AsuraBuildHash = regexp.MustCompile(`-[0-9a-f]{8}$`)
-
-// migrateAsuraKeys rewrites asura bookmarks whose series_id still carries
-// the build hash to the stable, hashless ID. Rows keyed with a hash are
-// orphaned on every Asura redeploy (old-hash URLs 302 to new-hash ones, so
-// detection yields a key that never matches). When two hash-generations of
-// one series collide, the row with the newest updated_at wins and the rest
-// are deleted. Idempotent: hashless IDs never match the regex.
-func migrateAsuraKeys(db *sql.DB) error {
-	rows, err := db.Query(`SELECT key, series_id, updated_at FROM bookmarks WHERE site = 'asura'`)
+// applyMigration runs one migration and records its version in the same
+// transaction, so an interrupted start leaves neither half behind.
+func applyMigration(db *sql.DB, version int64, body string) error {
+	tx, err := db.Begin()
 	if err != nil {
-		return fmt.Errorf("list asura rows: %w", err)
-	}
-	type row struct {
-		key, id string
-		updated int64
-	}
-	var all []row
-	for rows.Next() {
-		var r row
-		if err := rows.Scan(&r.key, &r.id, &r.updated); err != nil {
-			rows.Close()
-			return fmt.Errorf("scan asura row: %w", err)
-		}
-		all = append(all, r)
-	}
-	if err := rows.Close(); err != nil {
 		return err
 	}
+	defer tx.Rollback()
 
-	groups := map[string][]row{}
-	for _, r := range all {
-		stripped := AsuraBuildHash.ReplaceAllString(r.id, "")
-		groups[stripped] = append(groups[stripped], r)
+	var applied bool
+	if err := tx.QueryRow(
+		`SELECT EXISTS (SELECT 1 FROM schema_migrations WHERE version = $1)`,
+		version).Scan(&applied); err != nil {
+		return err
 	}
-	for stripped, g := range groups {
-		winner := 0
-		for i := range g {
-			if g[i].updated > g[winner].updated {
-				winner = i
-			}
-		}
-		// Losers go first: rewriting the winner to the stripped key while a
-		// pre-existing hashless row still holds it is a primary-key collision.
-		for i, r := range g {
-			if i == winner {
-				continue
-			}
-			if _, err := db.Exec(`DELETE FROM bookmarks WHERE key = ?`, r.key); err != nil {
-				return fmt.Errorf("drop duplicate %q: %w", r.key, err)
-			}
-		}
-		if r := g[winner]; r.id != stripped {
-			if _, err := db.Exec(
-				`UPDATE bookmarks SET key = ?, series_id = ? WHERE key = ?`,
-				"asura:"+stripped, stripped, r.key); err != nil {
-				return fmt.Errorf("rewrite key %q: %w", r.key, err)
-			}
-		}
+	if applied {
+		return nil
 	}
-	return nil
+	// No parameters, so this goes over the simple protocol and a migration may
+	// hold more than one statement.
+	if _, err := tx.Exec(body); err != nil {
+		return err
+	}
+	if _, err := tx.Exec(`INSERT INTO schema_migrations (version) VALUES ($1)`, version); err != nil {
+		return err
+	}
+	return tx.Commit()
 }
 
-func existingColumns(db *sql.DB, table string) (map[string]struct{}, error) {
-	rows, err := db.Query(`SELECT name FROM pragma_table_info(?)`, table)
-	if err != nil {
-		return nil, fmt.Errorf("read %s columns: %w", table, err)
-	}
-	defer rows.Close()
-
-	out := map[string]struct{}{}
-	for rows.Next() {
-		var name string
-		if err := rows.Scan(&name); err != nil {
-			return nil, fmt.Errorf("scan column name: %w", err)
-		}
-		out[name] = struct{}{}
-	}
-	return out, rows.Err()
-}
-
-// scanBookmark reads one row in bookmarkColumns order, translating SQLite's
-// integer bool and nullable latest_chapter_num into Go types.
-//
-// The optional columns are read through Null* types because rows predating
-// this code (or written by hand) may hold NULL where the app only ever writes
-// zero values. Only latest_chapter_num distinguishes the two: everywhere else
-// NULL and the zero value mean the same thing to clients.
+// scanBookmark reads one row in bookmarkColumns order. Every column is NOT
+// NULL except latest_chapter_num, where NULL means "never captured" — a
+// distinct state from chapter zero, and the reason for the pointer.
 func scanBookmark(scan func(...any) error) (Bookmark, error) {
 	var (
-		b                                          Bookmark
-		title, seriesURL, cover                    sql.NullString
-		lastChapter, lastChapterURL, latestChapter sql.NullString
-		status                                     sql.NullString
-		lastChapterNum, latestChapterNum           sql.NullFloat64
-		favorite                                   sql.NullInt64
+		b                Bookmark
+		latestChapterNum sql.NullFloat64
 	)
 	if err := scan(
-		&b.Key, &b.Site, &b.SeriesID, &title, &seriesURL, &cover,
-		&lastChapter, &lastChapterNum, &lastChapterURL,
-		&favorite, &latestChapter, &latestChapterNum, &b.UpdatedAt, &status, &b.Kind,
+		&b.Key, &b.Site, &b.SeriesID, &b.Title, &b.SeriesURL, &b.Cover,
+		&b.LastChapter, &b.LastChapterNum, &b.LastChapterURL,
+		&b.Favorite, &b.LatestChapter, &latestChapterNum, &b.UpdatedAt, &b.Status, &b.Kind,
 	); err != nil {
 		return Bookmark{}, err
 	}
-	b.Title = title.String
-	b.SeriesURL = seriesURL.String
-	b.Cover = cover.String
-	b.LastChapter = lastChapter.String
-	b.LastChapterNum = lastChapterNum.Float64
-	b.LastChapterURL = lastChapterURL.String
-	b.Favorite = favorite.Int64 != 0
-	b.LatestChapter = latestChapter.String
 	if latestChapterNum.Valid {
 		b.LatestChapterNum = &latestChapterNum.Float64
 	}
-	// A NULL, empty, or unrecognised bucket (e.g. a hand-edited row) would
-	// leave the row in no list at all, so anything outside the three known
-	// buckets reads as the default rather than being passed through.
-	b.Status = status.String
+	// An unrecognised bucket (a hand-edited row) would leave the row in no list
+	// at all, so anything outside the three known buckets reads as the default
+	// rather than being passed through.
 	if b.Status != StatusReading && b.Status != StatusArchived && b.Status != StatusFinished {
 		b.Status = StatusReading
 	}
@@ -365,7 +266,7 @@ func (s *Store) List() ([]Bookmark, error) {
 // the fields they do not touch.
 func (s *Store) Get(key string) (Bookmark, bool, error) {
 	b, err := scanBookmark(s.db.QueryRow(
-		`SELECT `+bookmarkColumns+` FROM bookmarks WHERE key = ?`, key).Scan)
+		`SELECT `+bookmarkColumns+` FROM bookmarks WHERE key = $1`, key).Scan)
 	if errors.Is(err, sql.ErrNoRows) {
 		return Bookmark{}, false, nil
 	}
@@ -395,9 +296,10 @@ func (s *Store) Upsert(b Bookmark) (Bookmark, error) {
 		latestNum = *b.LatestChapterNum
 	}
 
-	// IS NOT is SQLite's null-safe comparison. Within DO UPDATE, a bare column
-	// is the stored row and excluded.* is the incoming one; a brand-new key
-	// never reaches this clause, so it keeps the fresh timestamp from VALUES.
+	// IS DISTINCT FROM is Postgres's null-safe comparison, and it is what
+	// implements the ordering rule. Within DO UPDATE, a bare column is the
+	// stored row and excluded.* is the incoming one; a brand-new key never
+	// reaches this clause, so it keeps the fresh timestamp from VALUES.
 	//
 	// The status and kind columns resolve on the VALUES side, not in the
 	// conflict clause: excluded.* is the row *after* these expressions are
@@ -408,12 +310,16 @@ func (s *Store) Upsert(b Bookmark) (Bookmark, error) {
 	// stored", and only a brand-new row falls through to the literal
 	// default. The subquery runs inside this transaction, so it sees the
 	// row this statement is about to conflict with.
+	//
+	// The ::text casts are load-bearing: inside COALESCE/NULLIF there is no
+	// target column to infer the parameter type from, and Postgres rejects the
+	// statement rather than guessing.
 	if _, err := tx.Exec(`
 		INSERT INTO bookmarks (`+bookmarkColumns+`)
-		VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?,
-		        COALESCE(NULLIF(?, ''), (SELECT status FROM bookmarks WHERE key = ?), 'reading'),
-		        COALESCE(NULLIF(?, ''), (SELECT kind FROM bookmarks WHERE key = ?), 'manga'))
-		ON CONFLICT(key) DO UPDATE SET
+		VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11, $12, $13,
+		        COALESCE(NULLIF($14::text, ''), (SELECT status FROM bookmarks WHERE key = $1), 'reading'),
+		        COALESCE(NULLIF($15::text, ''), (SELECT kind FROM bookmarks WHERE key = $1), 'manga'))
+		ON CONFLICT (key) DO UPDATE SET
 		  site=excluded.site, series_id=excluded.series_id, title=excluded.title,
 		  series_url=excluded.series_url, cover=excluded.cover,
 		  last_chapter=excluded.last_chapter, last_chapter_num=excluded.last_chapter_num,
@@ -424,20 +330,19 @@ func (s *Store) Upsert(b Bookmark) (Bookmark, error) {
 		  status=excluded.status,
 		  kind=excluded.kind,
 		  updated_at=CASE
-		    WHEN bookmarks.last_chapter_num IS NOT excluded.last_chapter_num
+		    WHEN bookmarks.last_chapter_num IS DISTINCT FROM excluded.last_chapter_num
 		    THEN excluded.updated_at
 		    ELSE bookmarks.updated_at
 		  END`,
 		b.Key, b.Site, b.SeriesID, b.Title, b.SeriesURL, b.Cover,
 		b.LastChapter, b.LastChapterNum, b.LastChapterURL,
 		b.Favorite, b.LatestChapter, latestNum, b.UpdatedAt,
-		b.Status, b.Key,
-		b.Kind, b.Key); err != nil {
+		b.Status, b.Kind); err != nil {
 		return Bookmark{}, fmt.Errorf("upsert %q: %w", b.Key, err)
 	}
 
 	stored, err := scanBookmark(tx.QueryRow(
-		`SELECT `+bookmarkColumns+` FROM bookmarks WHERE key = ?`, b.Key).Scan)
+		`SELECT `+bookmarkColumns+` FROM bookmarks WHERE key = $1`, b.Key).Scan)
 	if err != nil {
 		return Bookmark{}, fmt.Errorf("read back %q: %w", b.Key, err)
 	}
@@ -449,7 +354,7 @@ func (s *Store) Upsert(b Bookmark) (Bookmark, error) {
 
 // Delete removes a bookmark by key. Deleting a missing key is not an error.
 func (s *Store) Delete(key string) error {
-	if _, err := s.db.Exec(`DELETE FROM bookmarks WHERE key = ?`, key); err != nil {
+	if _, err := s.db.Exec(`DELETE FROM bookmarks WHERE key = $1`, key); err != nil {
 		return fmt.Errorf("delete %q: %w", key, err)
 	}
 	return nil
@@ -472,11 +377,11 @@ func (s *Store) Delete(key string) error {
 func (s *Store) DueForLatestCheck(cutoffMs int64, limit int) ([]Bookmark, error) {
 	rows, err := s.db.Query(`SELECT `+bookmarkColumns+`
 		FROM bookmarks
-		WHERE series_url IS NOT NULL AND series_url <> ''
-		  AND status IS NOT 'finished'
-		  AND latest_checked_at <= ?
+		WHERE series_url <> ''
+		  AND status IS DISTINCT FROM 'finished'
+		  AND latest_checked_at <= $1
 		ORDER BY latest_checked_at ASC
-		LIMIT ?`, cutoffMs, limit)
+		LIMIT $2`, cutoffMs, limit)
 	if err != nil {
 		return nil, fmt.Errorf("query due bookmarks: %w", err)
 	}
@@ -505,7 +410,7 @@ func (s *Store) DueForLatestCheck(cutoffMs int64, limit int) ([]Bookmark, error)
 // long as the user kept reading it.
 func (s *Store) MarkLatestChecked(key string, ts int64) error {
 	if _, err := s.db.Exec(
-		`UPDATE bookmarks SET latest_checked_at = ? WHERE key = ?`, ts, key); err != nil {
+		`UPDATE bookmarks SET latest_checked_at = $1 WHERE key = $2`, ts, key); err != nil {
 		return fmt.Errorf("mark checked %q: %w", key, err)
 	}
 	return nil
@@ -518,7 +423,7 @@ func (s *Store) MarkLatestChecked(key string, ts int64) error {
 func (s *Store) LatestCheckedAt(key string) (int64, error) {
 	var ts int64
 	if err := s.db.QueryRow(
-		`SELECT latest_checked_at FROM bookmarks WHERE key = ?`, key).Scan(&ts); err != nil {
+		`SELECT latest_checked_at FROM bookmarks WHERE key = $1`, key).Scan(&ts); err != nil {
 		return 0, fmt.Errorf("latest checked at %q: %w", key, err)
 	}
 	return ts, nil

backend/internal/store/store_test.go

@@ -1,80 +1,54 @@
 package store
 
 import (
-	"database/sql"
-	"path/filepath"
+	"os"
 	"testing"
 	"time"
+
+	"bookmarkmanager/backend/internal/pgtest"
 )
 
+func TestMain(m *testing.M) { os.Exit(pgtest.Main(m)) }
+
 func newTestStore(t *testing.T) *Store {
 	t.Helper()
-	store, err := Open(filepath.Join(t.TempDir(), "test.db"))
+	store, err := Open(pgtest.URL(t))
 	if err != nil {
-		t.Fatalf("OpenStore: %v", err)
+		t.Fatalf("Open: %v", err)
 	}
 	t.Cleanup(func() { store.Close() })
 	return store
 }
 
-func TestOpenStoreMigratesLegacySchema(t *testing.T) {
-	dbPath := filepath.Join(t.TempDir(), "legacy.db")
-
-	legacy, err := sql.Open("sqlite", dbPath)
+// The migration runner runs on every start, so a second Open against a
+// database it already built must be a no-op rather than a duplicate-table
+// error, and must leave the rows alone.
+func TestOpenIsIdempotent(t *testing.T) {
+	url := pgtest.URL(t)
+	first, err := Open(url)
 	if err != nil {
-		t.Fatalf("open legacy db: %v", err)
+		t.Fatalf("Open: %v", err)
 	}
-	if _, err := legacy.Exec(`
-		CREATE TABLE bookmarks (
-		  key              TEXT PRIMARY KEY,
-		  site             TEXT NOT NULL,
-		  series_id        TEXT NOT NULL,
-		  title            TEXT,
-		  series_url       TEXT,
-		  cover            TEXT,
-		  last_chapter     TEXT,
-		  last_chapter_num REAL,
-		  last_chapter_url TEXT,
-		  updated_at       INTEGER NOT NULL
-		)`); err != nil {
-		t.Fatalf("create legacy schema: %v", err)
-	}
-	if _, err := legacy.Exec(`
-		INSERT INTO bookmarks (key, site, series_id, title, last_chapter, last_chapter_num, updated_at)
-		VALUES ('asura:legacy', 'asura', 'legacy', 'Legacy Series', 'Chapter 7', 7, 123)`); err != nil {
-		t.Fatalf("seed legacy row: %v", err)
-	}
-	if err := legacy.Close(); err != nil {
-		t.Fatalf("close legacy db: %v", err)
+	if _, err := first.Upsert(Bookmark{
+		Key: "asura:solo", Site: "asura", SeriesID: "solo", UpdatedAt: 1000,
+	}); err != nil {
+		t.Fatalf("seed: %v", err)
 	}
+	first.Close()
 
-	store, err := Open(dbPath)
+	second, err := Open(url)
 	if err != nil {
-		t.Fatalf("OpenStore on legacy db: %v", err)
+		t.Fatalf("reopen: %v", err)
 	}
-	t.Cleanup(func() { store.Close() })
+	t.Cleanup(func() { second.Close() })
 
-	list, err := store.List()
+	list, err := second.List()
 	if err != nil {
 		t.Fatalf("List: %v", err)
 	}
-	if len(list) != 1 || list[0].Key != "asura:legacy" {
-		t.Fatalf("legacy row lost: %+v", list)
+	if len(list) != 1 || list[0].Key != "asura:solo" {
+		t.Fatalf("rows after reopen = %+v, want only the seeded one", list)
 	}
-	got := list[0]
-	if got.Title != "Legacy Series" || got.LastChapterNum != 7 || got.UpdatedAt != 123 {
-		t.Fatalf("legacy data mangled: %+v", got)
-	}
-	if got.Favorite || got.LatestChapter != "" || got.LatestChapterNum != nil {
-		t.Fatalf("new columns should default empty, got %+v", got)
-	}
-
-	// Reopening an already-migrated database must be a no-op, not an error.
-	store2, err := Open(dbPath)
-	if err != nil {
-		t.Fatalf("OpenStore is not idempotent: %v", err)
-	}
-	store2.Close()
 }
 
 func TestStoreGet(t *testing.T) {
@@ -155,7 +129,7 @@ func readLatestCheckedAt(t *testing.T, s *Store, key string) int64 {
 	t.Helper()
 	var ts int64
 	if err := s.db.QueryRow(
-		`SELECT latest_checked_at FROM bookmarks WHERE key = ?`, key).Scan(&ts); err != nil {
+		`SELECT latest_checked_at FROM bookmarks WHERE key = $1`, key).Scan(&ts); err != nil {
 		t.Fatalf("read latest_checked_at %q: %v", key, err)
 	}
 	return ts
@@ -264,53 +238,6 @@ func TestUpsertPreservesLatestCheckedAt(t *testing.T) {
 	}
 }
 
-// migrateColumns must be able to bring a database created before this column up
-// to date, not just create it fresh.
-func TestMigrateAddsLatestCheckedAt(t *testing.T) {
-	path := filepath.Join(t.TempDir(), "old.db")
-
-	old, err := sql.Open("sqlite", path)
-	if err != nil {
-		t.Fatalf("open: %v", err)
-	}
-	// A pre-latest_checked_at table, matching the schema as it shipped before.
-	if _, err := old.Exec(`CREATE TABLE bookmarks (
-		key TEXT PRIMARY KEY, site TEXT NOT NULL, series_id TEXT NOT NULL,
-		title TEXT, series_url TEXT, cover TEXT,
-		last_chapter TEXT, last_chapter_num REAL, last_chapter_url TEXT,
-		favorite INTEGER NOT NULL DEFAULT 0,
-		latest_chapter TEXT NOT NULL DEFAULT '', latest_chapter_num REAL,
-		updated_at INTEGER NOT NULL)`); err != nil {
-		t.Fatalf("create old table: %v", err)
-	}
-	if _, err := old.Exec(
-		`INSERT INTO bookmarks (key, site, series_id, series_url, updated_at)
-		 VALUES ('asura:x', 'asura', 'x', 'https://asurascans.com/comics/x', 5)`); err != nil {
-		t.Fatalf("seed old row: %v", err)
-	}
-	if err := old.Close(); err != nil {
-		t.Fatalf("close: %v", err)
-	}
-
-	s, err := Open(path)
-	if err != nil {
-		t.Fatalf("OpenStore on pre-existing db: %v", err)
-	}
-	t.Cleanup(func() { s.Close() })
-
-	// The migrated row must default to 0 (never checked) and so be due.
-	if got := readLatestCheckedAt(t, s, "asura:x"); got != 0 {
-		t.Fatalf("migrated latest_checked_at = %d, want 0", got)
-	}
-	due, err := s.DueForLatestCheck(1000, 10)
-	if err != nil {
-		t.Fatalf("DueForLatestCheck: %v", err)
-	}
-	if len(due) != 1 {
-		t.Fatalf("got %d due rows after migration, want 1", len(due))
-	}
-}
-
 func TestUpsertDefaultsStatusToReading(t *testing.T) {
 	store := newTestStore(t)
 	stored, err := store.Upsert(Bookmark{
@@ -425,41 +352,6 @@ func TestUpsertStatusChangeKeepsUpdatedAt(t *testing.T) {
 	}
 }
 
-// A database written before the column existed must gain it, with every
-// pre-existing row landing in the reading bucket.
-func TestMigrationAddsStatusToLegacyDatabase(t *testing.T) {
-	path := filepath.Join(t.TempDir(), "legacy.db")
-	db, err := sql.Open("sqlite", path)
-	if err != nil {
-		t.Fatalf("open: %v", err)
-	}
-	if _, err := db.Exec(`
-		CREATE TABLE bookmarks (
-		  key TEXT PRIMARY KEY, site TEXT NOT NULL, series_id TEXT NOT NULL,
-		  title TEXT, series_url TEXT, cover TEXT,
-		  last_chapter TEXT, last_chapter_num REAL, last_chapter_url TEXT,
-		  updated_at INTEGER NOT NULL);
-		INSERT INTO bookmarks (key, site, series_id, updated_at)
-		VALUES ('asura:old', 'asura', 'old', 1)`); err != nil {
-		t.Fatalf("seed legacy: %v", err)
-	}
-	db.Close()
-
-	store, err := Open(path)
-	if err != nil {
-		t.Fatalf("OpenStore: %v", err)
-	}
-	defer store.Close()
-
-	b, ok, err := store.Get("asura:old")
-	if err != nil || !ok {
-		t.Fatalf("Get: ok=%v err=%v", ok, err)
-	}
-	if b.Status != StatusReading {
-		t.Fatalf("Status = %q, want %q", b.Status, StatusReading)
-	}
-}
-
 // Archiving is the reason to keep polling — the point is to come back to a
 // series that has moved on. A finished series has nothing left to publish.
 func TestDueForLatestCheckSkipsFinishedKeepsArchived(t *testing.T) {
@@ -494,135 +386,6 @@ func TestDueForLatestCheckSkipsFinishedKeepsArchived(t *testing.T) {
 	}
 }
 
-// Asura slugs used to include the site build hash; rows keyed with it must
-// be rewritten to the stable ID on open, merging hash-generations of the
-// same series into the newest row.
-func TestOpenStoreMigratesAsuraBuildHashKeys(t *testing.T) {
-	dbPath := filepath.Join(t.TempDir(), "hash.db")
-
-	store, err := Open(dbPath)
-	if err != nil {
-		t.Fatalf("open: %v", err)
-	}
-	seed := []Bookmark{
-		{Key: "asura:swordmasters-youngest-son-f886a8af", Site: "asura",
-			SeriesID: "swordmasters-youngest-son-f886a8af", Title: "Old gen",
-			LastChapterNum: 50, UpdatedAt: 100},
-		{Key: "asura:swordmasters-youngest-son-059befe1", Site: "asura",
-			SeriesID: "swordmasters-youngest-son-059befe1", Title: "Re-bookmarked",
-			LastChapterNum: 60, UpdatedAt: 200},
-		{Key: "asura:overgeared-059befe1", Site: "asura",
-			SeriesID: "overgeared-059befe1", Title: "Single gen", UpdatedAt: 150},
-		// Hash-like suffix on another site must be left alone.
-		{Key: "demonic:x-deadbeef", Site: "demonic",
-			SeriesID: "x-deadbeef", Title: "Not asura", UpdatedAt: 300},
-	}
-	for _, b := range seed {
-		if _, err := store.Upsert(b); err != nil {
-			t.Fatalf("seed %s: %v", b.Key, err)
-		}
-	}
-	if err := store.Close(); err != nil {
-		t.Fatalf("close: %v", err)
-	}
-
-	reopened, err := Open(dbPath)
-	if err != nil {
-		t.Fatalf("reopen: %v", err)
-	}
-	t.Cleanup(func() { reopened.Close() })
-
-	list, err := reopened.List()
-	if err != nil {
-		t.Fatalf("List: %v", err)
-	}
-	byKey := map[string]Bookmark{}
-	for _, b := range list {
-		byKey[b.Key] = b
-	}
-	if len(list) != 3 {
-		t.Fatalf("want 3 rows after merge, got %d: %+v", len(list), list)
-	}
-	merged, ok := byKey["asura:swordmasters-youngest-son"]
-	if !ok {
-		t.Fatalf("merged key missing: %+v", byKey)
-	}
-	// Newest row wins the merge.
-	if merged.Title != "Re-bookmarked" || merged.LastChapterNum != 60 || merged.UpdatedAt != 200 {
-		t.Fatalf("merge kept wrong row: %+v", merged)
-	}
-	if merged.SeriesID != "swordmasters-youngest-son" {
-		t.Fatalf("series_id not stripped: %q", merged.SeriesID)
-	}
-	if _, ok := byKey["asura:overgeared-059befe1"]; ok {
-		t.Fatal("single-generation hashed key not rewritten")
-	}
-	if _, ok := byKey["asura:overgeared"]; !ok {
-		t.Fatal("single-generation row missing under stripped key")
-	}
-	if _, ok := byKey["demonic:x-deadbeef"]; !ok {
-		t.Fatal("non-asura row touched")
-	}
-
-	// Idempotent: a third open changes nothing.
-	third, err := Open(dbPath)
-	if err != nil {
-		t.Fatalf("third open: %v", err)
-	}
-	third.Close()
-}
-
-// A hashed row and a pre-existing hashless row of the same series collide on
-// the stripped key. The winner rewrite must happen only after the loser is
-// gone, or the UPDATE hits a primary-key collision and OpenStore fails.
-func TestOpenStoreMigratesAsuraHashlessCollision(t *testing.T) {
-	dbPath := filepath.Join(t.TempDir(), "collision.db")
-
-	store, err := Open(dbPath)
-	if err != nil {
-		t.Fatalf("open: %v", err)
-	}
-	seed := []Bookmark{
-		{Key: "asura:overgeared", Site: "asura", SeriesID: "overgeared",
-			Title: "Hashless", LastChapterNum: 10, UpdatedAt: 100},
-		{Key: "asura:overgeared-059befe1", Site: "asura",
-			SeriesID: "overgeared-059befe1", Title: "Hashed newer",
-			LastChapterNum: 20, UpdatedAt: 200},
-	}
-	for _, b := range seed {
-		if _, err := store.Upsert(b); err != nil {
-			t.Fatalf("seed %s: %v", b.Key, err)
-		}
-	}
-	if err := store.Close(); err != nil {
-		t.Fatalf("close: %v", err)
-	}
-
-	reopened, err := Open(dbPath)
-	if err != nil {
-		t.Fatalf("reopen: %v", err)
-	}
-	t.Cleanup(func() { reopened.Close() })
-
-	list, err := reopened.List()
-	if err != nil {
-		t.Fatalf("List: %v", err)
-	}
-	if len(list) != 1 {
-		t.Fatalf("want 1 row after merge, got %d: %+v", len(list), list)
-	}
-	merged := list[0]
-	if merged.Key != "asura:overgeared" {
-		t.Fatalf("merged key = %q, want asura:overgeared", merged.Key)
-	}
-	if merged.SeriesID != "overgeared" {
-		t.Fatalf("series_id = %q, want overgeared", merged.SeriesID)
-	}
-	if merged.Title != "Hashed newer" || merged.LastChapterNum != 20 || merged.UpdatedAt != 200 {
-		t.Fatalf("merge kept wrong row: %+v", merged)
-	}
-}
-
 func TestDisplayChapter(t *testing.T) {
 	cases := []struct {
 		name string
@@ -713,51 +476,3 @@ func TestUpsertEmptyKindKeepsStoredValue(t *testing.T) {
 		t.Fatalf("LastChapterNum = %v, want 11 — progress in the same request must still land", got.LastChapterNum)
 	}
 }
-
-// A database created before this column exists must gain it, backfilled as
-// manga, without losing anything.
-func TestLegacyDatabaseGainsKindAsManga(t *testing.T) {
-	dbPath := filepath.Join(t.TempDir(), "legacy.db")
-
-	legacy, err := sql.Open("sqlite", dbPath)
-	if err != nil {
-		t.Fatalf("open legacy db: %v", err)
-	}
-	if _, err := legacy.Exec(`
-		CREATE TABLE bookmarks (
-		  key              TEXT PRIMARY KEY,
-		  site             TEXT NOT NULL,
-		  series_id        TEXT NOT NULL,
-		  title            TEXT,
-		  series_url       TEXT,
-		  cover            TEXT,
-		  last_chapter     TEXT,
-		  last_chapter_num REAL,
-		  last_chapter_url TEXT,
-		  updated_at       INTEGER NOT NULL
-		)`); err != nil {
-		t.Fatalf("create legacy schema: %v", err)
-	}
-	if _, err := legacy.Exec(`
-		INSERT INTO bookmarks (key, site, series_id, title, updated_at)
-		VALUES ('asura:legacy', 'asura', 'legacy', 'Legacy Series', 123)`); err != nil {
-		t.Fatalf("seed legacy row: %v", err)
-	}
-	if err := legacy.Close(); err != nil {
-		t.Fatalf("close legacy db: %v", err)
-	}
-
-	store, err := Open(dbPath)
-	if err != nil {
-		t.Fatalf("Open on legacy db: %v", err)
-	}
-	t.Cleanup(func() { store.Close() })
-
-	list, err := store.List()
-	if err != nil {
-		t.Fatalf("List: %v", err)
-	}
-	if len(list) != 1 || list[0].Kind != KindManga {
-		t.Fatalf("legacy row should backfill as manga, got %+v", list)
-	}
-}