Function findContentChanges

scripts/develop/dbrecovery.go:261–316

findContentChanges compares tracked up/down SQL against disk for all tracked versions whose files still exist.

(ctx context.Context, db *sql.DB, migrDir string)

// findContentChanges compares tracked up/down SQL against disk
// for all tracked versions whose files still exist.
func findContentChanges(ctx context.Context, db *sql.DB, migrDir string) ([]contentChange, error) {
	rows, err := db.QueryContext(ctx, `
		SELECT version, filename, up_sql, down_sql
		FROM _develop.applied_migrations
		ORDER BY version
	`)
	if err != nil {
		return nil, xerrors.Errorf("query tracking table: %w", err)
	}
	defer rows.Close()

	var changes []contentChange
	for rows.Next() {
		var version int
		var filename, trackedUp, trackedDown string
		if err := rows.Scan(&version, &filename, &trackedUp, &trackedDown); err != nil {
			return nil, xerrors.Errorf("scan row: %w", err)
		}

		// Only check files that exist on disk (missing files
		// are handled by findRollbacks).
		downPath := filepath.Join(migrDir, filename)
		if _, err := os.Stat(downPath); err != nil {
			continue
		}

		// Derive up filename from down filename.
		upFilename := strings.Replace(filename, ".down.sql", ".up.sql", 1)

		diskDown, err := os.ReadFile(filepath.Join(migrDir, filename))
		if err != nil {
			continue
		}
		diskUp, err := os.ReadFile(filepath.Join(migrDir, upFilename))
		if err != nil {
			continue
		}

		upChanged := trackedUp != "" && trackedUp != string(diskUp)
		downChanged := trackedDown != "" && trackedDown != string(diskDown)

		if upChanged || downChanged {
			changes = append(changes, contentChange{
				version:     version,
				filename:    filename,
				upChanged:   upChanged,
				downChanged: downChanged,
				trackedUp:   trackedUp,
				diskUp:      string(diskUp),
				trackedDown: trackedDown,
				diskDown:    string(diskDown),
			})
		}
	}
	return changes, rows.Err()
}

func maxTrackedVersion(ctx context.Context, db *sql.DB) (int, error) {