images: remove the docker field

The 'docker' bit on model.Image was unused at runtime — every code
path that branched on it had been removed earlier, leaving only the
field, the SQL column, the --docker flag, and the
#feature:docker sentinel that BuildMetadataPackages emitted into a
hash file. None of those have callers anymore.

Strip the field from the model, the API params, the SQLite column,
the CLI flag, and BuildMetadataPackages's signature. Add migration
2 (drop_images_docker) so existing installs lose the column on next
daemon start. ALTER TABLE ... DROP COLUMN is fine: SQLite has
supported it since 3.35 (2021).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

internal/api/types.go

@@ -158,7 +158,6 @@ type ImageRegisterParams struct {
 	InitrdPath   string `json:"initrd_path,omitempty"`
 	ModulesDir   string `json:"modules_dir,omitempty"`
 	KernelRef    string `json:"kernel_ref,omitempty"`
-	Docker       bool   `json:"docker,omitempty"`
 }
 
 type ImagePullParams struct {

internal/cli/cli_test.go

@@ -309,7 +309,7 @@ func TestImageRegisterFlagsExist(t *testing.T) {
 	if err != nil {
 		t.Fatalf("find register: %v", err)
 	}
-	for _, flagName := range []string{"name", "rootfs", "work-seed", "kernel", "initrd", "modules", "docker"} {
+	for _, flagName := range []string{"name", "rootfs", "work-seed", "kernel", "initrd", "modules"} {
 		if register.Flags().Lookup(flagName) == nil {
 			t.Fatalf("missing flag %q", flagName)
 		}

internal/cli/commands_image.go

@@ -80,7 +80,6 @@ func (d *deps) newImageRegisterCommand() *cobra.Command {
 	cmd.Flags().StringVar(&params.InitrdPath, "initrd", "", "initrd path")
 	cmd.Flags().StringVar(&params.ModulesDir, "modules", "", "modules dir")
 	cmd.Flags().StringVar(&params.KernelRef, "kernel-ref", "", "name of a cataloged kernel (see 'banger kernel list')")
-	cmd.Flags().BoolVar(&params.Docker, "docker", false, "mark image as docker-prepared")
 	_ = cmd.RegisterFlagCompletionFunc("kernel-ref", d.completeKernelNames)
 	return cmd
 }

internal/daemon/imagemgr/paths.go

@@ -129,14 +129,9 @@ func StageOptionalArtifactPath(artifactDir, stagedPath, name string) string {
 }
 
 // BuildMetadataPackages returns the canonical package set recorded for a
-// managed image build. The #feature:docker sentinel is appended when
+// managed image build.
-// docker is requested.
+func BuildMetadataPackages() []string {
-func BuildMetadataPackages(docker bool) []string {
+	return DebianBasePackages()
-	packages := DebianBasePackages()
-	if docker {
-		packages = append(packages, "#feature:docker")
-	}
-	return packages
 }
 
 // WritePackagesMetadata writes the hash of packages next to rootfsPath so

internal/daemon/images.go

@@ -64,7 +64,6 @@ func (s *ImageService) RegisterImage(ctx context.Context, params api.ImageRegist
 		image.KernelPath = kernelPath
 		image.InitrdPath = initrdPath
 		image.ModulesDir = modulesDir
-		image.Docker = params.Docker
 		image.UpdatedAt = now
 	case errors.Is(lookupErr, sql.ErrNoRows):
 		id, idErr := model.NewID()
@@ -80,7 +79,6 @@ func (s *ImageService) RegisterImage(ctx context.Context, params api.ImageRegist
 			KernelPath:   kernelPath,
 			InitrdPath:   initrdPath,
 			ModulesDir:   modulesDir,
-			Docker:       params.Docker,
 			CreatedAt:    now,
 			UpdatedAt:    now,
 		}

internal/model/types.go

@@ -76,7 +76,6 @@ type Image struct {
 	ModulesDir                    string    `json:"modules_dir,omitempty"`
 	BuildSize                     string    `json:"build_size,omitempty"`
 	SeededSSHPublicKeyFingerprint string    `json:"seeded_ssh_public_key_fingerprint,omitempty"`
-	Docker                        bool      `json:"docker"`
 	CreatedAt                     time.Time `json:"created_at"`
 	UpdatedAt                     time.Time `json:"updated_at"`
 }

internal/store/migrations.go

@@ -24,6 +24,7 @@ type migration struct {
 // entries — installed DBs key off the id column.
 var migrations = []migration{
 	{id: 1, name: "baseline", up: migrateBaseline},
+	{id: 2, name: "drop_images_docker", up: migrateDropImagesDocker},
 }
 
 // runMigrations ensures schema_migrations exists, then applies every
@@ -141,3 +142,13 @@ func migrateBaseline(tx *sql.Tx) error {
 	}
 	return nil
 }
+
+// migrateDropImagesDocker removes the legacy images.docker column.
+// SQLite supports ALTER TABLE ... DROP COLUMN since 3.35 (2021), and
+// banger ships against modern SQLite, so a single statement is enough.
+// Existing values are simply discarded — the field never affected
+// runtime behaviour.
+func migrateDropImagesDocker(tx *sql.Tx) error {
+	_, err := tx.Exec(`ALTER TABLE images DROP COLUMN docker;`)
+	return err
+}

internal/store/store.go

@@ -123,8 +123,8 @@ func (s *Store) UpsertImage(ctx context.Context, image model.Image) error {
 	const query = `
 	INSERT INTO images (
 		id, name, managed, artifact_dir, rootfs_path, work_seed_path, kernel_path, initrd_path,
-		modules_dir, build_size, seeded_ssh_public_key_fingerprint, docker, created_at, updated_at
+		modules_dir, build_size, seeded_ssh_public_key_fingerprint, created_at, updated_at
-	) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
+	) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
 	ON CONFLICT(id) DO UPDATE SET
 		name=excluded.name,
 		managed=excluded.managed,
@@ -136,7 +136,6 @@ func (s *Store) UpsertImage(ctx context.Context, image model.Image) error {
 		modules_dir=excluded.modules_dir,
 		build_size=excluded.build_size,
 		seeded_ssh_public_key_fingerprint=excluded.seeded_ssh_public_key_fingerprint,
-		docker=excluded.docker,
 		updated_at=excluded.updated_at`
 	_, err := s.db.ExecContext(ctx, query,
 		image.ID,
@@ -150,7 +149,6 @@ func (s *Store) UpsertImage(ctx context.Context, image model.Image) error {
 		image.ModulesDir,
 		image.BuildSize,
 		image.SeededSSHPublicKeyFingerprint,
-		boolToInt(image.Docker),
 		image.CreatedAt.Format(time.RFC3339),
 		image.UpdatedAt.Format(time.RFC3339),
 	)
@@ -158,15 +156,15 @@ func (s *Store) UpsertImage(ctx context.Context, image model.Image) error {
 }
 
 func (s *Store) GetImageByName(ctx context.Context, name string) (model.Image, error) {
-	return s.getImage(ctx, "SELECT id, name, managed, artifact_dir, rootfs_path, work_seed_path, kernel_path, initrd_path, modules_dir, build_size, seeded_ssh_public_key_fingerprint, docker, created_at, updated_at FROM images WHERE name = ?", name)
+	return s.getImage(ctx, "SELECT id, name, managed, artifact_dir, rootfs_path, work_seed_path, kernel_path, initrd_path, modules_dir, build_size, seeded_ssh_public_key_fingerprint, created_at, updated_at FROM images WHERE name = ?", name)
 }
 
 func (s *Store) GetImageByID(ctx context.Context, id string) (model.Image, error) {
-	return s.getImage(ctx, "SELECT id, name, managed, artifact_dir, rootfs_path, work_seed_path, kernel_path, initrd_path, modules_dir, build_size, seeded_ssh_public_key_fingerprint, docker, created_at, updated_at FROM images WHERE id = ?", id)
+	return s.getImage(ctx, "SELECT id, name, managed, artifact_dir, rootfs_path, work_seed_path, kernel_path, initrd_path, modules_dir, build_size, seeded_ssh_public_key_fingerprint, created_at, updated_at FROM images WHERE id = ?", id)
 }
 
 func (s *Store) ListImages(ctx context.Context) ([]model.Image, error) {
-	rows, err := s.db.QueryContext(ctx, "SELECT id, name, managed, artifact_dir, rootfs_path, work_seed_path, kernel_path, initrd_path, modules_dir, build_size, seeded_ssh_public_key_fingerprint, docker, created_at, updated_at FROM images ORDER BY created_at ASC")
+	rows, err := s.db.QueryContext(ctx, "SELECT id, name, managed, artifact_dir, rootfs_path, work_seed_path, kernel_path, initrd_path, modules_dir, build_size, seeded_ssh_public_key_fingerprint, created_at, updated_at FROM images ORDER BY created_at ASC")
 	if err != nil {
 		return nil, err
 	}
@@ -356,7 +354,7 @@ type scanner interface {
 
 func scanImageRow(row scanner) (model.Image, error) {
 	var image model.Image
-	var managed, docker int
+	var managed int
 	var workSeedPath sql.NullString
 	var seededSSHPublicKeyFingerprint sql.NullString
 	var createdAt, updatedAt string
@@ -372,7 +370,6 @@ func scanImageRow(row scanner) (model.Image, error) {
 		&image.ModulesDir,
 		&image.BuildSize,
 		&seededSSHPublicKeyFingerprint,
-		&docker,
 		&createdAt,
 		&updatedAt,
 	)
@@ -380,7 +377,6 @@ func scanImageRow(row scanner) (model.Image, error) {
 		return image, err
 	}
 	image.Managed = managed == 1
-	image.Docker = docker == 1
 	image.WorkSeedPath = workSeedPath.String
 	image.SeededSSHPublicKeyFingerprint = seededSSHPublicKeyFingerprint.String
 	image.CreatedAt, err = time.Parse(time.RFC3339, createdAt)

internal/store/store_test.go

@@ -179,8 +179,8 @@ func TestGetImageRejectsMalformedTimestamp(t *testing.T) {
 	_, err := store.db.ExecContext(ctx, `
 		INSERT INTO images (
 			id, name, managed, artifact_dir, rootfs_path, kernel_path, initrd_path,
-			modules_dir, build_size, docker, created_at, updated_at
+			modules_dir, build_size, created_at, updated_at
-		) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)`,
+		) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)`,
 		"image-bad-time",
 		"image-bad-time",
 		0,
@@ -190,7 +190,6 @@ func TestGetImageRejectsMalformedTimestamp(t *testing.T) {
 		"",
 		"",
 		"",
-		0,
 		"not-a-time",
 		"not-a-time",
 	)
@@ -398,7 +397,6 @@ func sampleImage(name string) model.Image {
 		ModulesDir:                    "/modules/" + name,
 		BuildSize:                     "8G",
 		SeededSSHPublicKeyFingerprint: "seeded-fingerprint",
-		Docker:                        true,
 		CreatedAt:                     now,
 		UpdatedAt:                     now,
 	}