Debug Library — Introspection

The debug library provides runtime introspection tools for analyzing code at runtime.

Stack inspection:

• debug.traceback() — generates a formatted stack trace string
• debug.info(level, flags) — gets info about a function at call stack level
• debug.info(func, flags) — gets info about a specific function

Flags for debug.info: "n" name, "l" line, "s" source, "f" func itself

Upvalue access:

• debug.getupvalues(func) — returns table of {name, value} for all upvalues
• debug.setupvalue(func, index, value) — modify an upvalue by index

Upvalues are the outer local variables captured by a closure — debug can read and modify them.

Constants:

• debug.getconstants(func) — returns all constants (strings, numbers) used in function bytecode

Local variable access:

• debug.getlocal(level, index) — read local variable from a stack frame
• debug.setlocal(level, index, value) — modify it

Note: Many debug functions are restricted or removed in standard Roblox scripts. Full access requires an executor environment.