fix(auth): harden oauth identity upgrade paths

backend/internal/repository/migrations_runner.go

@@ -51,6 +51,8 @@ CREATE TABLE IF NOT EXISTS atlas_schema_revisions (
 const migrationsAdvisoryLockID int64 = 694208311321144027
 const migrationsLockRetryInterval = 500 * time.Millisecond
 const nonTransactionalMigrationSuffix = "_notx.sql"
+const paymentOrdersOutTradeNoUniqueMigration = "120_enforce_payment_orders_out_trade_no_unique_notx.sql"
+const paymentOrdersOutTradeNoUniqueIndex = "paymentorder_out_trade_no_unique"
 
 type migrationChecksumCompatibilityRule struct {
 	fileChecksum       string
@@ -65,9 +67,11 @@ var migrationChecksumCompatibilityRules = map[string]migrationChecksumCompatibil
 	"054_drop_legacy_cache_columns.sql":                       newMigrationChecksumCompatibilityRule("82de761156e03876653e7a6a4eee883cd927847036f779b0b9f34c42a8af7a7d", "182c193f3359946cf094090cd9e57d5c3fd9abaffbc1e8fc378646b8a6fa12b4"),
 	"061_add_usage_log_request_type.sql":                      newMigrationChecksumCompatibilityRule("66207e7aa5dd0429c2e2c0fabdaf79783ff157fa0af2e81adff2ee03790ec65c", "08a248652cbab7cfde147fc6ef8cda464f2477674e20b718312faa252e0481c0", "222b4a09c797c22e5922b6b172327c824f5463aaa8760e4f621bc5c22e2be0f3"),
 	"109_auth_identity_compat_backfill.sql":                   newMigrationChecksumCompatibilityRule("2b380305e73ff0c13aa8c811e45897f2b36ca4a438f7b3e8f98e19ecb6bae0b3", "551e498aa5616d2d91096e9d72cf9fb36e418ee22eacc557f8811cadbc9e20ee"),
+	"115_auth_identity_legacy_external_backfill.sql":          newMigrationChecksumCompatibilityRule("022aadd97bb53e755f0cf7a3a957e0cb1a1353b0c39ec4de3234acd2871fd04f", "4cf39e508be9fd1a5aa41610cbbebeb80385c9adda45bf78a706de9db4f1385f"),
+	"116_auth_identity_legacy_external_safety_reports.sql":    newMigrationChecksumCompatibilityRule("07edb09fa8d04ffb172b0621e3c22f4d1757d20a24ae267b3b36b087ab72d488", "f7757bd929ac67ffb08ce69fa4cf20fad39dbff9d5a5085fb2adabb7607e5877"),
 	"118_wechat_dual_mode_and_auth_source_defaults.sql":       newMigrationChecksumCompatibilityRule("b54194d7a3e4fbf710e0a3590d22a2fe7966804c487052a356e0b55f53ef96b0", "e0cdf835d6c688d64100f483d31bc02ac9ebad414bf1837af239a84bf75b8227"),
 	"119_enforce_payment_orders_out_trade_no_unique.sql":      newMigrationChecksumCompatibilityRule("0bbe809ae48a9d811dabda1ba1c74955bd71c4a9cc610f9128816818dfa6c11e", "ebd2c67cce0116393fb4f1b5d5116a67c6aceb73820dfb5133d1ff6f36d72d34"),
-	"120_enforce_payment_orders_out_trade_no_unique_notx.sql": newMigrationChecksumCompatibilityRule("707431450603e70a43ce9fbd61e0c12fa67da4875158ccefabacea069587ab22", "04b082b5a239c525154fe9185d324ee2b05ff90da9297e10dba19f9be79aa59a"),
+	"120_enforce_payment_orders_out_trade_no_unique_notx.sql": newMigrationChecksumCompatibilityRule("34aadc0db59a4e390f92a12b73bd74642d9724f33124f73638ae00089ea5e074", "e77921f79d539bc24575cb9c16cbe566d2b23ce816190343d0a7568f6a3fcf61", "707431450603e70a43ce9fbd61e0c12fa67da4875158ccefabacea069587ab22", "04b082b5a239c525154fe9185d324ee2b05ff90da9297e10dba19f9be79aa59a"),
 	"123_fix_legacy_auth_source_grant_on_signup_defaults.sql": newMigrationChecksumCompatibilityRule("2ce43c2cd89e9f9e1febd34a407ed9e84d177386c5544b6f02c1f58a21129f57", "6cd33422f215dcd1f486ab6f35c0ea5805d9ca69bb25906d94bc649156657145"),
 }
 
@@ -195,6 +199,10 @@ func applyMigrationsFS(ctx context.Context, db *sql.DB, fsys fs.FS) error {
 		}
 
 		if nonTx {
+			if err := prepareNonTransactionalMigration(ctx, db, name); err != nil {
+				return fmt.Errorf("prepare migration %s: %w", name, err)
+			}
+
 			// *_notx.sql：用于 CREATE/DROP INDEX CONCURRENTLY 场景，必须非事务执行。
 			// 逐条语句执行，避免将多条 CONCURRENTLY 语句放入同一个隐式事务块。
 			statements := splitSQLStatements(content)
@@ -244,6 +252,88 @@ func applyMigrationsFS(ctx context.Context, db *sql.DB, fsys fs.FS) error {
 	return nil
 }
 
+func prepareNonTransactionalMigration(ctx context.Context, db *sql.DB, name string) error {
+	switch name {
+	case paymentOrdersOutTradeNoUniqueMigration:
+		return preparePaymentOrdersOutTradeNoUniqueMigration(ctx, db)
+	default:
+		return nil
+	}
+}
+
+func preparePaymentOrdersOutTradeNoUniqueMigration(ctx context.Context, db *sql.DB) error {
+	duplicates, err := findDuplicatePaymentOrderOutTradeNos(ctx, db)
+	if err != nil {
+		return fmt.Errorf("precheck duplicate out_trade_no: %w", err)
+	}
+	if len(duplicates) > 0 {
+		return fmt.Errorf(
+			"duplicate out_trade_no values block %s; remediate duplicates before retrying: %s",
+			paymentOrdersOutTradeNoUniqueMigration,
+			strings.Join(duplicates, ", "),
+		)
+	}
+
+	invalid, err := indexIsInvalid(ctx, db, paymentOrdersOutTradeNoUniqueIndex)
+	if err != nil {
+		return fmt.Errorf("check invalid index %s: %w", paymentOrdersOutTradeNoUniqueIndex, err)
+	}
+	if !invalid {
+		return nil
+	}
+
+	if _, err := db.ExecContext(ctx, fmt.Sprintf("DROP INDEX CONCURRENTLY IF EXISTS %s", paymentOrdersOutTradeNoUniqueIndex)); err != nil {
+		return fmt.Errorf("drop invalid index %s: %w", paymentOrdersOutTradeNoUniqueIndex, err)
+	}
+	return nil
+}
+
+func findDuplicatePaymentOrderOutTradeNos(ctx context.Context, db *sql.DB) ([]string, error) {
+	rows, err := db.QueryContext(ctx, `
+		SELECT out_trade_no, COUNT(*) AS duplicate_count
+		FROM payment_orders
+		WHERE out_trade_no <> ''
+		GROUP BY out_trade_no
+		HAVING COUNT(*) > 1
+		ORDER BY duplicate_count DESC, out_trade_no
+		LIMIT 5
+	`)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	duplicates := make([]string, 0, 5)
+	for rows.Next() {
+		var outTradeNo string
+		var duplicateCount int
+		if err := rows.Scan(&outTradeNo, &duplicateCount); err != nil {
+			return nil, err
+		}
+		duplicates = append(duplicates, fmt.Sprintf("%s (count=%d)", outTradeNo, duplicateCount))
+	}
+	if err := rows.Err(); err != nil {
+		return nil, err
+	}
+	return duplicates, nil
+}
+
+func indexIsInvalid(ctx context.Context, db *sql.DB, indexName string) (bool, error) {
+	var invalid bool
+	err := db.QueryRowContext(ctx, `
+		SELECT EXISTS (
+			SELECT 1
+			FROM pg_class idx
+			JOIN pg_namespace ns ON ns.oid = idx.relnamespace
+			JOIN pg_index i ON i.indexrelid = idx.oid
+			WHERE ns.nspname = 'public'
+			  AND idx.relname = $1
+			  AND NOT i.indisvalid
+		)
+	`, indexName).Scan(&invalid)
+	return invalid, err
+}
+
 func ensureAtlasBaselineAligned(ctx context.Context, db *sql.DB, fsys fs.FS) error {
 	hasLegacy, err := tableExists(ctx, db, "schema_migrations")
 	if err != nil {