Change schema_migrations version from TEXT to INTEGER

Per review: the SQL file should be self-contained. 000.sql now
includes both the CREATE TABLE and the INSERT OR IGNORE for recording
its own version. Removed the separate INSERT from Go code in
bootstrapMigrationsTable().

internal/database/database.go

@@ -9,6 +9,7 @@ import (
 	"log/slog"
 	"path/filepath"
 	"sort"
+	"strconv"
 	"strings"
 
 	"go.uber.org/fx"
@@ -21,6 +22,10 @@ import (
 //go:embed schema/*.sql
 var schemaFS embed.FS
 
+// bootstrapVersion is the migration that creates the schema_migrations
+// table itself. It is applied before the normal migration loop.
+const bootstrapVersion = 0
+
 // Params defines dependencies for Database.
 type Params struct {
 	fx.In
@@ -38,35 +43,40 @@ type Database struct {
 // ParseMigrationVersion extracts the numeric version prefix from a migration
 // filename. Filenames must follow the pattern "<version>.sql" or
 // "<version>_<description>.sql", where version is a zero-padded numeric
-// string (e.g. "001", "002"). Returns the version string and an error if
+// string (e.g. "001", "002"). Returns the version as an integer and an
-// the filename does not match the expected pattern.
+// error if the filename does not match the expected pattern.
-func ParseMigrationVersion(filename string) (string, error) {
+func ParseMigrationVersion(filename string) (int, error) {
 	name := strings.TrimSuffix(filename, filepath.Ext(filename))
 	if name == "" {
-		return "", fmt.Errorf("invalid migration filename %q: empty name", filename)
+		return 0, fmt.Errorf("invalid migration filename %q: empty name", filename)
 	}
 
 	// Split on underscore to separate version from description.
 	// If there's no underscore, the entire stem is the version.
-	version := name
+	versionStr := name
 	if idx := strings.IndexByte(name, '_'); idx >= 0 {
-		version = name[:idx]
+		versionStr = name[:idx]
 	}
 
-	if version == "" {
+	if versionStr == "" {
-		return "", fmt.Errorf("invalid migration filename %q: empty version prefix", filename)
+		return 0, fmt.Errorf("invalid migration filename %q: empty version prefix", filename)
 	}
 
 	// Validate the version is purely numeric.
-	for _, ch := range version {
+	for _, ch := range versionStr {
 		if ch < '0' || ch > '9' {
-			return "", fmt.Errorf(
+			return 0, fmt.Errorf(
 				"invalid migration filename %q: version %q contains non-numeric character %q",
-				filename, version, string(ch),
+				filename, versionStr, string(ch),
 			)
 		}
 	}
 
+	version, err := strconv.Atoi(versionStr)
+	if err != nil {
+		return 0, fmt.Errorf("invalid migration filename %q: %w", filename, err)
+	}
+
 	return version, nil
 }
 
@@ -143,17 +153,34 @@ func collectMigrations() ([]string, error) {
 	return migrations, nil
 }
 
-// ensureMigrationsTable creates the schema_migrations tracking table if
+// bootstrapMigrationsTable ensures the schema_migrations table exists
-// it does not already exist.
+// by applying 000.sql if the table is missing.
-func ensureMigrationsTable(ctx context.Context, db *sql.DB) error {
+func bootstrapMigrationsTable(ctx context.Context, db *sql.DB, log *slog.Logger) error {
-	_, err := db.ExecContext(ctx, `
+	var tableExists int
-		CREATE TABLE IF NOT EXISTS schema_migrations (
+
-			version TEXT PRIMARY KEY,
+	err := db.QueryRowContext(ctx,
-			applied_at DATETIME DEFAULT CURRENT_TIMESTAMP
+		"SELECT COUNT(*) FROM sqlite_master WHERE type='table' AND name='schema_migrations'",
-		)
+	).Scan(&tableExists)
-	`)
 	if err != nil {
-		return fmt.Errorf("failed to create migrations table: %w", err)
+		return fmt.Errorf("failed to check for migrations table: %w", err)
+	}
+
+	if tableExists > 0 {
+		return nil
+	}
+
+	content, err := schemaFS.ReadFile("schema/000.sql")
+	if err != nil {
+		return fmt.Errorf("failed to read bootstrap migration 000.sql: %w", err)
+	}
+
+	if log != nil {
+		log.Info("applying bootstrap migration", "version", bootstrapVersion)
+	}
+
+	_, err = db.ExecContext(ctx, string(content))
+	if err != nil {
+		return fmt.Errorf("failed to apply bootstrap migration: %w", err)
 	}
 
 	return nil
@@ -164,7 +191,7 @@ func ensureMigrationsTable(ctx context.Context, db *sql.DB) error {
 // This is exported so tests can apply the real schema without the full fx
 // lifecycle.
 func ApplyMigrations(ctx context.Context, db *sql.DB, log *slog.Logger) error {
-	if err := ensureMigrationsTable(ctx, db); err != nil {
+	if err := bootstrapMigrationsTable(ctx, db, log); err != nil {
 		return err
 	}
 

internal/database/database_test.go

@@ -8,37 +8,51 @@ import (
 	_ "modernc.org/sqlite" // SQLite driver registration
 )
 
+// openTestDB returns a fresh in-memory SQLite database.
+func openTestDB(t *testing.T) *sql.DB {
+	t.Helper()
+
+	db, err := sql.Open("sqlite", ":memory:")
+	if err != nil {
+		t.Fatalf("failed to open test db: %v", err)
+	}
+
+	t.Cleanup(func() { db.Close() })
+
+	return db
+}
+
 func TestParseMigrationVersion(t *testing.T) {
 	tests := []struct {
 		name     string
 		filename string
-		want     string
+		want     int
 		wantErr  bool
 	}{
 		{
 			name:     "version only",
 			filename: "001.sql",
-			want:     "001",
+			want:     1,
 		},
 		{
 			name:     "version with description",
 			filename: "001_initial_schema.sql",
-			want:     "001",
+			want:     1,
 		},
 		{
 			name:     "multi-digit version",
 			filename: "042_add_indexes.sql",
-			want:     "042",
+			want:     42,
 		},
 		{
 			name:     "long version number",
 			filename: "00001_long_prefix.sql",
-			want:     "00001",
+			want:     1,
 		},
 		{
 			name:     "description with multiple underscores",
 			filename: "003_add_user_auth_tables.sql",
-			want:     "003",
+			want:     3,
 		},
 		{
 			name:     "empty filename",
@@ -67,7 +81,7 @@ func TestParseMigrationVersion(t *testing.T) {
 			got, err := ParseMigrationVersion(tt.filename)
 			if tt.wantErr {
 				if err == nil {
-					t.Errorf("ParseMigrationVersion(%q) expected error, got %q", tt.filename, got)
+					t.Errorf("ParseMigrationVersion(%q) expected error, got %d", tt.filename, got)
 				}
 
 				return
@@ -80,76 +94,131 @@ func TestParseMigrationVersion(t *testing.T) {
 			}
 
 			if got != tt.want {
-				t.Errorf("ParseMigrationVersion(%q) = %q, want %q", tt.filename, got, tt.want)
+				t.Errorf("ParseMigrationVersion(%q) = %d, want %d", tt.filename, got, tt.want)
 			}
 		})
 	}
 }
 
-func TestApplyMigrations(t *testing.T) {
+func TestApplyMigrations_CreatesSchemaAndTables(t *testing.T) {
-	db, err := sql.Open("sqlite", ":memory:")
+	db := openTestDB(t)
-	if err != nil {
+	ctx := context.Background()
-		t.Fatalf("failed to open in-memory database: %v", err)
-	}
-	defer db.Close()
 
-	// Apply migrations should succeed.
+	if err := ApplyMigrations(ctx, db, nil); err != nil {
-	if err := ApplyMigrations(context.Background(), db, nil); err != nil {
 		t.Fatalf("ApplyMigrations failed: %v", err)
 	}
 
-	// Verify the schema_migrations table recorded the version.
+	// The schema_migrations table must exist and contain at least
-	var version string
+	// version 0 (the bootstrap) and 1 (the initial schema).
-
+	rows, err := db.Query("SELECT version FROM schema_migrations ORDER BY version")
-	err = db.QueryRowContext(context.Background(),
-		"SELECT version FROM schema_migrations LIMIT 1",
-	).Scan(&version)
 	if err != nil {
 		t.Fatalf("failed to query schema_migrations: %v", err)
 	}
+	defer rows.Close()
 
-	if version != "001" {
+	var versions []int
-		t.Errorf("expected version %q, got %q", "001", version)
+	for rows.Next() {
+		var v int
+		if err := rows.Scan(&v); err != nil {
+			t.Fatalf("failed to scan version: %v", err)
 		}
 
-	// Verify a table from the migration exists (source_content).
+		versions = append(versions, v)
-	var tableName string
-
-	err = db.QueryRowContext(context.Background(),
-		"SELECT name FROM sqlite_master WHERE type='table' AND name='source_content'",
-	).Scan(&tableName)
-	if err != nil {
-		t.Fatalf("expected source_content table to exist: %v", err)
-	}
-}
-
-func TestApplyMigrationsIdempotent(t *testing.T) {
-	db, err := sql.Open("sqlite", ":memory:")
-	if err != nil {
-		t.Fatalf("failed to open in-memory database: %v", err)
-	}
-	defer db.Close()
-
-	// Apply twice should succeed (idempotent).
-	if err := ApplyMigrations(context.Background(), db, nil); err != nil {
-		t.Fatalf("first ApplyMigrations failed: %v", err)
 	}
 
-	if err := ApplyMigrations(context.Background(), db, nil); err != nil {
+	if err := rows.Err(); err != nil {
-		t.Fatalf("second ApplyMigrations failed: %v", err)
+		t.Fatalf("row iteration error: %v", err)
 	}
 
-	// Should still have exactly one migration recorded.
+	if len(versions) < 2 {
+		t.Fatalf("expected at least 2 migrations recorded, got %d: %v", len(versions), versions)
+	}
+
+	if versions[0] != 0 {
+		t.Errorf("first recorded migration = %d, want %d", versions[0], 0)
+	}
+
+	if versions[1] != 1 {
+		t.Errorf("second recorded migration = %d, want %d", versions[1], 1)
+	}
+
+	// Verify that the application tables created by 001.sql exist.
+	for _, table := range []string{"source_content", "source_metadata", "output_content", "request_cache", "negative_cache", "cache_stats"} {
 		var count int
 
-	err = db.QueryRowContext(context.Background(),
+		err := db.QueryRow(
-		"SELECT COUNT(*) FROM schema_migrations",
+			"SELECT COUNT(*) FROM sqlite_master WHERE type='table' AND name=?",
+			table,
 		).Scan(&count)
 		if err != nil {
-		t.Fatalf("failed to count schema_migrations: %v", err)
+			t.Fatalf("failed to check for table %s: %v", table, err)
 		}
 
 		if count != 1 {
-		t.Errorf("expected 1 migration record, got %d", count)
+			t.Errorf("table %s does not exist after migrations", table)
+		}
+	}
+}
+
+func TestApplyMigrations_Idempotent(t *testing.T) {
+	db := openTestDB(t)
+	ctx := context.Background()
+
+	if err := ApplyMigrations(ctx, db, nil); err != nil {
+		t.Fatalf("first ApplyMigrations failed: %v", err)
+	}
+
+	// Running a second time must succeed without errors.
+	if err := ApplyMigrations(ctx, db, nil); err != nil {
+		t.Fatalf("second ApplyMigrations failed: %v", err)
+	}
+
+	// Verify no duplicate rows in schema_migrations.
+	var count int
+
+	err := db.QueryRow("SELECT COUNT(*) FROM schema_migrations WHERE version = 0").Scan(&count)
+	if err != nil {
+		t.Fatalf("failed to count version 0 rows: %v", err)
+	}
+
+	if count != 1 {
+		t.Errorf("expected exactly 1 row for version 0, got %d", count)
+	}
+}
+
+func TestBootstrapMigrationsTable_FreshDatabase(t *testing.T) {
+	db := openTestDB(t)
+	ctx := context.Background()
+
+	if err := bootstrapMigrationsTable(ctx, db, nil); err != nil {
+		t.Fatalf("bootstrapMigrationsTable failed: %v", err)
+	}
+
+	// schema_migrations table must exist.
+	var tableCount int
+
+	err := db.QueryRow(
+		"SELECT COUNT(*) FROM sqlite_master WHERE type='table' AND name='schema_migrations'",
+	).Scan(&tableCount)
+	if err != nil {
+		t.Fatalf("failed to check for table: %v", err)
+	}
+
+	if tableCount != 1 {
+		t.Fatalf("schema_migrations table not created")
+	}
+
+	// Version 0 must be recorded.
+	var recorded int
+
+	err = db.QueryRow(
+		"SELECT COUNT(*) FROM schema_migrations WHERE version = 0",
+	).Scan(&recorded)
+	if err != nil {
+		t.Fatalf("failed to check version: %v", err)
+	}
+
+	if recorded != 1 {
+		t.Errorf("expected version 0 to be recorded, got count %d", recorded)
 	}
 }

internal/database/schema/000.sql

@@ -0,0 +1,9 @@
+-- Migration 000: Schema migrations tracking table
+-- Applied as a bootstrap step before the normal migration loop.
+
+CREATE TABLE IF NOT EXISTS schema_migrations (
+    version INTEGER PRIMARY KEY,
+    applied_at DATETIME DEFAULT CURRENT_TIMESTAMP
+);
+
+INSERT OR IGNORE INTO schema_migrations (version) VALUES (0);