feat: v1→v2 config schema migration for seid v6.5 write mode rename (#25)

* feat: v1→v2 config schema migration for seid v6.5 write mode rename

seid v6.5 (sei-chain commit 0412e4e84) replaced the WriteMode enum to
model the FlatKV migration lifecycle. cosmos_only → memiavl_only is now
the breaking change that crashes any node provisioned with the old default.

Changes:
- types.go: add v2 WriteMode constants (memiavl_only, migrate_evm,
  evm_migrated, migrate_all_but_bank, all_migrated_but_bank,
  migrate_bank, flatkv_only, test_only_dual_write); update IsValid() to
  v2 values; keep v1 constants as Deprecated for migration reference
- defaults.go: change StateCommit and StateStore WriteMode defaults from
  WriteModeCosmosOnly → WriteModeMemiavlOnly
- config.go: bump CurrentVersion 1 → 2
- migrate.go: register v1→v2 migration (renames cosmos_only, dual_write,
  split_write in both StateCommit and StateStore WriteMode); add
  SeidVersionForSchema map so each schema version is traceable to its
  seid version boundary
- config_test.go: update TestWriteMode_Validity for v2 semantics

Fixes: #24

Co-Authored-By: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>

* test: add v1→v2 migration round-trip and edge case coverage

Co-Authored-By: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>

* fix: address cross-review findings on v2 write mode migration

- types.go: remove WriteModeEVMOnly — never a real deployed value, had
  no migration target (would fail IsValid() after migration)
- migrate.go: delete SeidVersionForSchema exported var (YAGNI — no
  programmatic consumer); fold version mapping into doc comment
- validate.go: add SeverityWarning for test_only_dual_write — valid per
  IsValid() to match seid's own parser, but explicitly flagged since
  sei-chain marks it "CRITICAL: never deploy to production"

Co-Authored-By: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>

Author: bdchatham

config.go

@@ -8,7 +8,7 @@ package seiconfig
 import "runtime"
 
 // CurrentVersion is the config schema version produced by this library.
-const CurrentVersion = 1
+const CurrentVersion = 2
 
 // DefaultSnapshotInterval is the default Tendermint state-sync snapshot
 // creation interval (in blocks) used when snapshot generation is enabled.

config_test.go

@@ -739,8 +739,11 @@ func TestNodeMode_IsFullnodeType(t *testing.T) {
 }
 
 func TestWriteMode_Validity(t *testing.T) {
-	if !WriteModeCosmosOnly.IsValid() {
-		t.Error("cosmos_only should be valid")
+	if !WriteModeMemiavlOnly.IsValid() {
+		t.Error("memiavl_only should be valid")
+	}
+	if WriteModeCosmosOnly.IsValid() {
+		t.Error("cosmos_only should not be valid in v2 (deprecated — use migration)")
 	}
 	if WriteMode("invalid").IsValid() {
 		t.Error("'invalid' should not be valid")

defaults.go

@@ -117,7 +117,7 @@ func baseDefaults() *SeiConfig {
 			IAVLDisableFastNode: true,
 			StateCommit: StateCommitConfig{
 				Enable:    true,
-				WriteMode: WriteModeCosmosOnly,
+				WriteMode: WriteModeMemiavlOnly,
 				ReadMode:  ReadModeCosmosOnly,
 			},
 			StateStore: StateStoreConfig{
@@ -128,7 +128,7 @@ func baseDefaults() *SeiConfig {
 				PruneIntervalSeconds: 600,
 				ImportNumWorkers:     1,
 				KeepLastVersion:      true,
-				WriteMode:            WriteModeCosmosOnly,
+				WriteMode:            WriteModeMemiavlOnly,
 				ReadMode:             ReadModeCosmosOnly,
 			},
 			ReceiptStore: ReceiptStoreConfig{

migrate.go

@@ -175,22 +175,33 @@ type AppliedMigration struct {
 // Default migration registry
 // ---------------------------------------------------------------------------
 
-// DefaultMigrations returns the set of all known migrations for the sei-config
-// schema. Currently empty since v1 is the initial version — migrations will be
-// added here as the schema evolves.
+// DefaultMigrations returns all known migrations for the sei-config schema.
 //
-// Example of a future migration:
+// Schema version to seid version mapping:
 //
-//	Migration{
-//	    FromVersion: 1,
-//	    ToVersion:   2,
-//	    Description: "Rename evm.checktx_timeout to evm.check_tx_timeout",
-//	    Migrate: func(cfg *SeiConfig) error {
-//	        // Field was renamed; value is preserved by the struct.
-//	        cfg.Version = 2
-//	        return nil
-//	    },
-//	}
+//	v1 → seid < v6.5   (cosmos_only write mode, legacy EVM routing)
+//	v2 → seid ≥ v6.5   (memiavl_only write mode, FlatKV migration scheme)
 func DefaultMigrations() []Migration {
-	return []Migration{}
+	return []Migration{
+		{
+			FromVersion: 1,
+			ToVersion:   2,
+			Description: "seid v6.5: rename WriteMode values to FlatKV migration scheme (cosmos_only→memiavl_only, dual_write→migrate_evm, split_write→evm_migrated)",
+			Migrate: func(cfg *SeiConfig) error {
+				rename := map[WriteMode]WriteMode{
+					WriteModeCosmosOnly: WriteModeMemiavlOnly,
+					WriteModeDualWrite:  WriteModeMigrateEVM,
+					WriteModeSplitWrite: WriteModeEVMMigrated,
+				}
+				if m, ok := rename[cfg.Storage.StateCommit.WriteMode]; ok {
+					cfg.Storage.StateCommit.WriteMode = m
+				}
+				if m, ok := rename[cfg.Storage.StateStore.WriteMode]; ok {
+					cfg.Storage.StateStore.WriteMode = m
+				}
+				cfg.Version = 2
+				return nil
+			},
+		},
+	}
 }

migrate_test.go

@@ -377,3 +377,96 @@ func TestDefaultMigrations_Valid(t *testing.T) {
 		t.Fatalf("DefaultMigrations failed to register: %v", err)
 	}
 }
+
+// v1ToV2Migration returns the v1→v2 migration from DefaultMigrations for tests
+// that exercise the rename transform directly (bypassing post-migration
+// validation, which rejects unknown/deprecated WriteMode values).
+func v1ToV2Migration(t *testing.T) Migration {
+	t.Helper()
+	for _, m := range DefaultMigrations() {
+		if m.FromVersion == 1 && m.ToVersion == 2 {
+			return m
+		}
+	}
+	t.Fatal("DefaultMigrations missing v1→v2 migration")
+	return Migration{}
+}
+
+// TestMigrateConfig_WriteModeRoundTrip runs the real v1→v2 migration through
+// the registry pipeline (including post-migration validation) and asserts the
+// deprecated cosmos_only write mode is renamed to memiavl_only in both stores.
+func TestMigrateConfig_WriteModeRoundTrip(t *testing.T) {
+	r, err := NewMigrationRegistry(DefaultMigrations()...)
+	if err != nil {
+		t.Fatalf("NewMigrationRegistry: %v", err)
+	}
+
+	cfg := DefaultForMode(ModeFull)
+	cfg.Version = 1
+	cfg.Storage.StateCommit.WriteMode = WriteModeCosmosOnly
+	cfg.Storage.StateStore.WriteMode = WriteModeCosmosOnly
+
+	result, err := r.MigrateConfig(cfg, 2)
+	if err != nil {
+		t.Fatalf("MigrateConfig: %v", err)
+	}
+
+	if cfg.Version != 2 {
+		t.Errorf("version: got %d, want 2", cfg.Version)
+	}
+	if cfg.Storage.StateCommit.WriteMode != WriteModeMemiavlOnly {
+		t.Errorf("state_commit.write_mode: got %q, want %q",
+			cfg.Storage.StateCommit.WriteMode, WriteModeMemiavlOnly)
+	}
+	if cfg.Storage.StateStore.WriteMode != WriteModeMemiavlOnly {
+		t.Errorf("state_store.write_mode: got %q, want %q",
+			cfg.Storage.StateStore.WriteMode, WriteModeMemiavlOnly)
+	}
+	if len(result.Applied) != 1 {
+		t.Fatalf("applied migrations: got %d, want 1", len(result.Applied))
+	}
+}
+
+// TestV1ToV2_WriteModeRename covers every deprecated v1 write mode and asserts
+// it maps to the expected v2 value. The unknown-value case asserts pass-through
+// (the migration only renames known values; validation handles the rest).
+func TestV1ToV2_WriteModeRename(t *testing.T) {
+	m := v1ToV2Migration(t)
+
+	tests := []struct {
+		name string
+		in   WriteMode
+		want WriteMode
+	}{
+		{"cosmos_only renames to memiavl_only", WriteModeCosmosOnly, WriteModeMemiavlOnly},
+		{"dual_write renames to migrate_evm", WriteModeDualWrite, WriteModeMigrateEVM},
+		{"split_write renames to evm_migrated", WriteModeSplitWrite, WriteModeEVMMigrated},
+		{"already-v2 memiavl_only is preserved", WriteModeMemiavlOnly, WriteModeMemiavlOnly},
+		{"unknown value passes through unchanged", WriteMode("future_mode"), WriteMode("future_mode")},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			cfg := DefaultForMode(ModeFull)
+			cfg.Version = 1
+			cfg.Storage.StateCommit.WriteMode = tc.in
+			cfg.Storage.StateStore.WriteMode = tc.in
+
+			if err := m.Migrate(cfg); err != nil {
+				t.Fatalf("Migrate: %v", err)
+			}
+
+			if cfg.Version != 2 {
+				t.Errorf("version: got %d, want 2", cfg.Version)
+			}
+			if cfg.Storage.StateCommit.WriteMode != tc.want {
+				t.Errorf("state_commit.write_mode: got %q, want %q",
+					cfg.Storage.StateCommit.WriteMode, tc.want)
+			}
+			if cfg.Storage.StateStore.WriteMode != tc.want {
+				t.Errorf("state_store.write_mode: got %q, want %q",
+					cfg.Storage.StateStore.WriteMode, tc.want)
+			}
+		})
+	}
+}

types.go

@@ -69,15 +69,27 @@ func Dur(d time.Duration) Duration {
 type WriteMode string
 
 const (
+	// v2 write modes — FlatKV migration lifecycle (sei-chain ≥ v6.5).
+	WriteModeMemiavlOnly        WriteMode = "memiavl_only"
+	WriteModeMigrateEVM         WriteMode = "migrate_evm"
+	WriteModeEVMMigrated        WriteMode = "evm_migrated"
+	WriteModeMigrateAllButBank  WriteMode = "migrate_all_but_bank"
+	WriteModeAllMigratedButBank WriteMode = "all_migrated_but_bank"
+	WriteModeMigrateBank        WriteMode = "migrate_bank"
+	WriteModeFlatKVOnly         WriteMode = "flatkv_only"
+	WriteModeTestOnlyDualWrite  WriteMode = "test_only_dual_write"
+
+	// Deprecated: v1 write modes, accepted only during v1→v2 migration.
 	WriteModeCosmosOnly WriteMode = "cosmos_only"
 	WriteModeDualWrite  WriteMode = "dual_write"
 	WriteModeSplitWrite WriteMode = "split_write"
-	WriteModeEVMOnly    WriteMode = "evm_only"
 )
 
 func (m WriteMode) IsValid() bool {
 	switch m {
-	case WriteModeCosmosOnly, WriteModeDualWrite, WriteModeSplitWrite, WriteModeEVMOnly:
+	case WriteModeMemiavlOnly, WriteModeMigrateEVM, WriteModeEVMMigrated,
+		WriteModeMigrateAllButBank, WriteModeAllMigratedButBank,
+		WriteModeMigrateBank, WriteModeFlatKVOnly, WriteModeTestOnlyDualWrite:
 		return true
 	default:
 		return false

validate.go

@@ -260,6 +260,9 @@ func validateStorage(r *ValidationResult, cfg *SeiConfig) {
 	if sc.WriteMode != "" && !sc.WriteMode.IsValid() {
 		r.addError("storage.state_commit.write_mode", fmt.Sprintf("invalid write_mode: %q", sc.WriteMode))
 	}
+	if sc.WriteMode == WriteModeTestOnlyDualWrite {
+		r.addWarning("storage.state_commit.write_mode", "test_only_dual_write must not be used in production")
+	}
 	if sc.ReadMode != "" && !sc.ReadMode.IsValid() {
 		r.addError("storage.state_commit.read_mode", fmt.Sprintf("invalid read_mode: %q", sc.ReadMode))
 	}