Fix(router): handle debug.getinfo returning nil for non-Lua functions

[PlumBlossomMaid]

Issue

debug.getinfo(fn, "Su") behaves differently depending on the function type:

• For pure Lua functions: returns a table with nparams field
• For C functions or wrapped callbacks: may return nil or a table without nparams

This inconsistency causes attempt to compare number with nil errors in layer.lua:57 and layer.lua:47 on Windows/Lua 5.1 environments.

Root Cause

The pegasus HTTP server passes some C-level callbacks and wrapped functions through the middleware chain. When these reach the layer handlers, debug.getinfo fails to extract parameter count information.

Fix

Added defensive checks before accessing nparams:

Before:

if debug.getinfo(fn, "Su").nparams > 3 then

After:

local info = debug.getinfo(fn, "Su")
if not info or not info.nparams or info.nparams > 3 then

Affected Functions

• LAYER_MT:handle_request
• LAYER_MT:handle_error

Environment

• OS: Windows 10
• Lua: 5.1.5
• Dependencies: pegasus 1.1.0, copas 4.10.0