payments/migration1: freeze core payment code

Copy the core payments/db code into payments/db/migration1 and
add the required sqlc-generated types/queries from sqldb/sqlc.
This effectively freezes the migration code so it stays robust
against future query or schema changes in the main payments package.

Replace the delegation to channeldb.ReadElement/WriteElement with
self-contained, frozen implementations that only handle the exact types
required by this migration package. This removes the dependency on the
live channeldb codec so that future changes to channeldb serialization
cannot silently corrupt or break the migration.

UnknownElementType is also defined locally for the same reason.

payments/db/migration1/sqlc/db.go

@@ -0,0 +1,31 @@
+// Code generated by sqlc. DO NOT EDIT.
+// versions:
+//   sqlc v1.29.0
+
+package sqlc
+
+import (
+	"context"
+	"database/sql"
+)
+
+type DBTX interface {
+	ExecContext(context.Context, string, ...interface{}) (sql.Result, error)
+	PrepareContext(context.Context, string) (*sql.Stmt, error)
+	QueryContext(context.Context, string, ...interface{}) (*sql.Rows, error)
+	QueryRowContext(context.Context, string, ...interface{}) *sql.Row
+}
+
+func New(db DBTX) *Queries {
+	return &Queries{db: db}
+}
+
+type Queries struct {
+	db DBTX
+}
+
+func (q *Queries) WithTx(tx *sql.Tx) *Queries {
+	return &Queries{
+		db: tx,
+	}
+}

payments/db/migration1/sqlc/db_custom.go

@@ -0,0 +1,123 @@
+package sqlc
+
+import (
+	"fmt"
+	"strings"
+)
+
+// GetTx returns the underlying DBTX (either *sql.DB or *sql.Tx) used by the
+// Queries struct.
+func (q *Queries) GetTx() DBTX {
+	return q.db
+}
+
+// makeQueryParams generates a string of query parameters for a SQL query. It is
+// meant to replace the `?` placeholders in a SQL query with numbered parameters
+// like `$1`, `$2`, etc. This is required for the sqlc /*SLICE:<field_name>*/
+// workaround. See scripts/gen_sqlc_docker.sh for more details.
+func makeQueryParams(numTotalArgs, numListArgs int) string {
+	if numListArgs == 0 {
+		return ""
+	}
+
+	var b strings.Builder
+
+	// Pre-allocate a rough estimation of the buffer size to avoid
+	// re-allocations. A parameter like $1000, takes 6 bytes.
+	b.Grow(numListArgs * 6)
+
+	diff := numTotalArgs - numListArgs
+	for i := 0; i < numListArgs; i++ {
+		if i > 0 {
+			// We don't need to check the error here because the
+			// WriteString method of strings.Builder always returns
+			// nil.
+			_, _ = b.WriteString(",")
+		}
+
+		// We don't need to check the error here because the
+		// Write method (called by fmt.Fprintf) of strings.Builder
+		// always returns nil.
+		_, _ = fmt.Fprintf(&b, "$%d", i+diff+1)
+	}
+
+	return b.String()
+}
+
+// PaymentAndIntent is an interface that provides access to a payment and its
+// associated payment intent.
+type PaymentAndIntent interface {
+	// GetPayment returns the Payment associated with this interface.
+	GetPayment() Payment
+
+	// GetPaymentIntent returns the PaymentIntent associated with this
+	// payment.
+	GetPaymentIntent() PaymentIntent
+}
+
+// GetPayment returns the Payment associated with this interface.
+//
+// NOTE: This method is part of the PaymentAndIntent interface.
+func (r FilterPaymentsRow) GetPayment() Payment {
+	return r.Payment
+}
+
+// GetPaymentIntent returns the PaymentIntent associated with this payment.
+// If the payment has no intent (IntentType is NULL), this returns a zero-value
+// PaymentIntent.
+//
+// NOTE: This method is part of the PaymentAndIntent interface.
+func (r FilterPaymentsRow) GetPaymentIntent() PaymentIntent {
+	if !r.IntentType.Valid {
+		return PaymentIntent{}
+	}
+
+	return PaymentIntent{
+		IntentType:    r.IntentType.Int16,
+		IntentPayload: r.IntentPayload,
+	}
+}
+
+// GetPayment returns the Payment associated with this interface.
+//
+// NOTE: This method is part of the PaymentAndIntent interface.
+func (r FetchPaymentRow) GetPayment() Payment {
+	return r.Payment
+}
+
+// GetPaymentIntent returns the PaymentIntent associated with this payment.
+// If the payment has no intent (IntentType is NULL), this returns a zero-value
+// PaymentIntent.
+//
+// NOTE: This method is part of the PaymentAndIntent interface.
+func (r FetchPaymentRow) GetPaymentIntent() PaymentIntent {
+	if !r.IntentType.Valid {
+		return PaymentIntent{}
+	}
+
+	return PaymentIntent{
+		IntentType:    r.IntentType.Int16,
+		IntentPayload: r.IntentPayload,
+	}
+}
+
+func (r FetchPaymentsByIDsRow) GetPayment() Payment {
+	return Payment{
+		ID:                r.ID,
+		AmountMsat:        r.AmountMsat,
+		CreatedAt:         r.CreatedAt,
+		PaymentIdentifier: r.PaymentIdentifier,
+		FailReason:        r.FailReason,
+	}
+}
+
+func (r FetchPaymentsByIDsRow) GetPaymentIntent() PaymentIntent {
+	if !r.IntentType.Valid {
+		return PaymentIntent{}
+	}
+
+	return PaymentIntent{
+		IntentType:    r.IntentType.Int16,
+		IntentPayload: r.IntentPayload,
+	}
+}

payments/db/migration1/sqlc/models.go

@@ -0,0 +1,110 @@
+// Code generated by sqlc. DO NOT EDIT.
+// versions:
+//   sqlc v1.29.0
+
+package sqlc
+
+import (
+	"database/sql"
+	"time"
+)
+
+type Payment struct {
+	ID                int64
+	AmountMsat        int64
+	CreatedAt         time.Time
+	PaymentIdentifier []byte
+	FailReason        sql.NullInt32
+}
+
+type PaymentAttemptFirstHopCustomRecord struct {
+	ID               int64
+	HtlcAttemptIndex int64
+	Key              int64
+	Value            []byte
+}
+
+type PaymentDuplicate struct {
+	ID             int64
+	PaymentID      int64
+	AmountMsat     int64
+	CreatedAt      time.Time
+	FailReason     sql.NullInt32
+	SettlePreimage []byte
+	SettleTime     sql.NullTime
+}
+
+type PaymentFirstHopCustomRecord struct {
+	ID        int64
+	PaymentID int64
+	Key       int64
+	Value     []byte
+}
+
+type PaymentHopCustomRecord struct {
+	ID    int64
+	HopID int64
+	Key   int64
+	Value []byte
+}
+
+type PaymentHtlcAttempt struct {
+	ID                 int64
+	AttemptIndex       int64
+	PaymentID          int64
+	SessionKey         []byte
+	AttemptTime        time.Time
+	PaymentHash        []byte
+	FirstHopAmountMsat int64
+	RouteTotalTimeLock int32
+	RouteTotalAmount   int64
+	RouteSourceKey     []byte
+}
+
+type PaymentHtlcAttemptResolution struct {
+	AttemptIndex       int64
+	ResolutionTime     time.Time
+	ResolutionType     int32
+	SettlePreimage     []byte
+	FailureSourceIndex sql.NullInt32
+	HtlcFailReason     sql.NullInt32
+	FailureMsg         []byte
+}
+
+type PaymentIntent struct {
+	ID            int64
+	PaymentID     int64
+	IntentType    int16
+	IntentPayload []byte
+}
+
+type PaymentRouteHop struct {
+	ID               int64
+	HtlcAttemptIndex int64
+	HopIndex         int32
+	PubKey           []byte
+	Scid             string
+	OutgoingTimeLock int32
+	AmtToForward     int64
+	MetaData         []byte
+}
+
+type PaymentRouteHopAmp struct {
+	HopID      int64
+	RootShare  []byte
+	SetID      []byte
+	ChildIndex int32
+}
+
+type PaymentRouteHopBlinded struct {
+	HopID               int64
+	EncryptedData       []byte
+	BlindingPoint       []byte
+	BlindedPathTotalAmt sql.NullInt64
+}
+
+type PaymentRouteHopMpp struct {
+	HopID       int64
+	PaymentAddr []byte
+	TotalMsat   int64
+}