csharpfritz/.squad/skills/static-config-pattern

Static Configuration Pattern

Confidence: low Source: earned

When to Use

When a class has compile-time constants (const) that need to become runtime-configurable without breaking existing consumers.

Pattern

1. Convert const fields to static T { get; private set; } = <original value>.
2. Add a public Configure*() method that sets the new values. Call once at startup.
3. Add an internal static Reset*() method that restores defaults — needed for test isolation since private set prevents external reset.
4. Ensure integer division preserves behavior: 7 / 2 = 3 matches the old hardcoded 3.

Key Considerations

• Default values must match the original constants exactly for backward compatibility.
• const → static property is a binary-breaking change (const values are inlined by the compiler). Only safe when all consumers are recompiled together (e.g., internal types, same solution).
• The Reset() method should be internal and gated behind InternalsVisibleTo so only test projects can call it.
• Place the Configure*() call in startup code before any consumer reads the properties.

Example

internal static class Layout
{
    public static int Size { get; private set; } = 7;

    public static void ConfigureExpanded() => Size = 15;

    internal static void ResetLayout() => Size = 7;
}