go-config-dead-type-removal

Answer

The removal surface is exactly 4 files. The one trap: TLSSConfig sits inside the dead NATS block but is still live — WebsocketConfig (and possibly HTTPServerConfig) embeds it. So the deletion is not a contiguous block delete.

Step 0 — grep dependents of EVERY type before touching anything

grep -rn -E "NATSConfig|NATSConnectionConfig|TLSSConfig|\.NATS" --include="*.go" .

Expected output: - NATSConfig, NATSConnectionConfig: referenced only in config.go, secrets.go, loader.go, loader_test.go → dead, safe to delete. - TLSSConfig: referenced by WebsocketConfig.TLS (live) → keep.

1. config.go — remove dead types + field, keep TLSSConfig

// BEFORE
type Config struct {
    // ...
    Websocket WebsocketConfig `yaml:"websocket" json:"websocket" mapstructure:"websocket"`
    NATS      NATSConfig      `yaml:"nats" json:"nats" mapstructure:"nats"` // DEAD since GAP-014
}

// Dead block (GAP-014 removed the NATS client):
type NATSConfig struct {
    Servers    []string              `yaml:"servers" json:"servers"`
    Connection NATSConnectionConfig  `yaml:"connection" json:"connection"`
}
type NATSConnectionConfig struct {
    Name     string     `yaml:"name" json:"name"`
    User     string     `yaml:"user" json:"user"`
    Password string     `yaml:"password" json:"password"`
    Token    string     `yaml:"token" json:"token"`
    TLS      TLSSConfig `yaml:"tls" json:"tls"` // <-- TRAP: type is mid-block but still live
}
type TLSSConfig struct { // still used by WebsocketConfig
    Enabled  bool   `yaml:"enabled" json:"enabled"`
    CertFile string `yaml:"cert_file" json:"cert_file"`
    KeyFile  string `yaml:"key_file" json:"key_file"`
}

// AFTER
type Config struct {
    // ...
    Websocket WebsocketConfig `yaml:"websocket" json:"websocket" mapstructure:"websocket"`
    // NATS field removed
}

// NATSConfig, NATSConnectionConfig deleted.
// TLSSConfig survives — move it adjacent to its live dependent for clarity:
type TLSSConfig struct {
    Enabled  bool   `yaml:"enabled" json:"enabled"`
    CertFile string `yaml:"cert_file" json:"cert_file"`
    KeyFile  string `yaml:"key_file" json:"key_file"`
}

2. secrets.go — delete the NATS secret-resolution block

func (c *Config) resolveSecrets(secrets SecretResolver) error {
    if secrets == nil {
        return nil
    }
    // DEAD block (removed):
    // if err := secrets.Resolve(&c.NATS.Connection.User); err != nil { return err }
    // if err := secrets.Resolve(&c.NATS.Connection.Password); err != nil { return err }
    // if err := secrets.Resolve(&c.NATS.Connection.Token); err != nil { return err }

    // live resolvers (websocket TLS, admin, etc.) remain untouched:
    if err := secrets.Resolve(&c.Websocket.TLS.CertFile); err != nil { return err }
    if err := secrets.Resolve(&c.Websocket.TLS.KeyFile); err != nil { return err }
    return nil
}

3. loader.go — remove NATS defaults and the nats merge key

// BEFORE
var defaultConfig = Config{
    Websocket: WebsocketConfig{Cors: WebsocketCORSConfig{AllowedOrigins: []string{"http://localhost"}}},
    NATS: NATSConfig{ // DEAD
        Servers:    []string{"nats://<ip-address>:4222"},
        Connection: NATSConnectionConfig{Name: "gateway"},
    },
}

var mergeKeys = []string{"nats", "websocket", "admin"} // remove "nats"

// AFTER
var defaultConfig = Config{
    Websocket: WebsocketConfig{Cors: WebsocketCORSConfig{AllowedOrigins: []string{"http://localhost"}}},
}

var mergeKeys = []string{"websocket", "admin"}

4. loader_test.go — rewrite TestSliceEnvOverride onto a live []string, don't delete it

The slice-override mechanism (comma-split env var → []string) is still needed; only its vehicle (nats.servers) died. Rewrite it against websocket.cors.allowed_origins:

func TestSliceEnvOverride(t *testing.T) {
    // GAP-014 removed nats.servers (the slice this test rode on). Rewrite the
    // mechanism test against the equivalent live []string field instead of
    // deleting it.
    t.Setenv("CONFIG_WEBSOCKET_CORS_ALLOWED_ORIGINS", "https://a.example,https://b.example")

    cfg, err := Load("testdata/config.yaml", WithEnvPrefix("CONFIG_"))
    require.NoError(t, err)
    require.Equal(t, []string{"https://a.example", "https://b.example"}, cfg.Websocket.Cors.AllowedOrigins)
}

Also delete the now-impossible assertions that referenced NATS defaults (e.g., TestLoadDefaults asserting cfg.NATS.Servers) — that's a removal, not a mechanism, so deletion is correct there.