Fix LuaShader crash when debug.getinfo is unavailable in gadget context

LuaShader:GetHandle/Delete/Activate/ActivateWith guard their "invalid
shader object" error path with `(debug and debug.getinfo(1).name)`. In
gadget (LuaRules) Lua the engine strips debug.getinfo while leaving the
debug table present, so the guard passes but debug.getinfo(1) is a nil
call -> uncaught error.

This turns a recoverable shader-compile failure into a fatal one: when a
shader fails to compile (e.g. gfx_overdrive_cables' geometry shader on a
driver lacking GL_ARB_gpu_shader5 in geometry shaders, such as older
llvmpipe), the gadget handles it gracefully via RemoveGadget, but
Shutdown -> cableShader:Finalize() then calls Delete() on a shader whose
shaderObj is nil, hitting the guard. The resulting error propagates out
of the pcall'd gadgets.lua include and aborts the ENTIRE LuaRules handle
("LuaRules is not loaded") instead of just disabling one effect.

Fix: also check that debug.getinfo exists before calling it. Applied to
all three vendored copies of LuaShader.lua.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: danfireman

LuaRules/Gadgets/Include/LuaShader.lua

@@ -196,7 +196,7 @@ function LuaShader:GetHandle()
 	if self.shaderObj ~= nil then
 		return self.shaderObj
 	else
-		local funcName = (debug and debug.getinfo(1).name) or "UnknownFunction"
+		local funcName = (debug and debug.getinfo and debug.getinfo(1).name) or "UnknownFunction"
 		self:ShowError(string.format("Attempt to use invalid shader object in [%s](). Did you call :Compile() or :Initialize()?", funcName))
 	end
 end
@@ -205,7 +205,7 @@ function LuaShader:Delete()
 	if self.shaderObj ~= nil then
 		gl.DeleteShader(self.shaderObj)
 	else
-		local funcName = (debug and debug.getinfo(1).name) or "UnknownFunction"
+		local funcName = (debug and debug.getinfo and debug.getinfo(1).name) or "UnknownFunction"
 		self:ShowError(string.format("Attempt to use invalid shader object in [%s](). Did you call :Compile() or :Initialize()", funcName))
 	end
 end
@@ -217,7 +217,7 @@ function LuaShader:Activate()
 		self.active = true
 		return glUseShader(self.shaderObj)
 	else
-		local funcName = (debug and debug.getinfo(1).name) or "UnknownFunction"
+		local funcName = (debug and debug.getinfo and debug.getinfo(1).name) or "UnknownFunction"
 		self:ShowError(string.format("Attempt to use invalid shader object in [%s](). Did you call :Compile() or :Initialize()", funcName))
 		return false
 	end
@@ -238,7 +238,7 @@ function LuaShader:ActivateWith(func, ...)
 		glActiveShader(self.shaderObj, func, ...)
 		self.active = false
 	else
-		local funcName = (debug and debug.getinfo(1).name) or "UnknownFunction"
+		local funcName = (debug and debug.getinfo and debug.getinfo(1).name) or "UnknownFunction"
 		self:ShowError(string.format("Attempt to use invalid shader object in [%s](). Did you call :Compile() or :Initialize()", funcName))
 	end
 end

LuaUI/Widgets/Include/LuaShader.lua

@@ -758,7 +758,7 @@ function LuaShader:GetHandle()
 	if self.shaderObj ~= nil then
 		return self.shaderObj
 	else
-		local funcName = (debug and debug.getinfo(1).name) or "UnknownFunction"
+		local funcName = (debug and debug.getinfo and debug.getinfo(1).name) or "UnknownFunction"
 		self:ShowError(string.format("Attempt to use invalid shader object in [%s](). Did you call :Compile() or :Initialize()?", funcName))
 	end
 end
@@ -767,7 +767,7 @@ function LuaShader:Delete()
 	if self.shaderObj ~= nil then
 		gl.DeleteShader(self.shaderObj)
 	else
-		local funcName = (debug and debug.getinfo(1).name) or "UnknownFunction"
+		local funcName = (debug and debug.getinfo and debug.getinfo(1).name) or "UnknownFunction"
 		self:ShowError(string.format("Attempt to use invalid shader object in [%s](). Did you call :Compile() or :Initialize()", funcName))
 	end
 end
@@ -779,7 +779,7 @@ function LuaShader:Activate()
 		self.active = true
 		return glUseShader(self.shaderObj)
 	else
-		local funcName = (debug and debug.getinfo(1).name) or "UnknownFunction"
+		local funcName = (debug and debug.getinfo and debug.getinfo(1).name) or "UnknownFunction"
 		self:ShowError(string.format("Attempt to use invalid shader object in [%s](). Did you call :Compile() or :Initialize()", funcName))
 		return false
 	end
@@ -800,7 +800,7 @@ function LuaShader:ActivateWith(func, ...)
 		glActiveShader(self.shaderObj, func, ...)
 		self.active = false
 	else
-		local funcName = (debug and debug.getinfo(1).name) or "UnknownFunction"
+		local funcName = (debug and debug.getinfo and debug.getinfo(1).name) or "UnknownFunction"
 		self:ShowError(string.format("Attempt to use invalid shader object in [%s](). Did you call :Compile() or :Initialize()", funcName))
 	end
 end

modules/graphics/LuaShader.lua

@@ -929,7 +929,7 @@ function LuaShader:GetHandle()
 	if self.shaderObj ~= nil then
 		return self.shaderObj
 	else
-		local funcName = (debug and debug.getinfo(1).name) or "UnknownFunction"
+		local funcName = (debug and debug.getinfo and debug.getinfo(1).name) or "UnknownFunction"
 		self:ShowError(string.format("Attempt to use invalid shader object in [%s](). Did you call :Compile() or :Initialize()?", funcName))
 	end
 end
@@ -938,7 +938,7 @@ function LuaShader:Delete()
 	if self.shaderObj ~= nil then
 		gl.DeleteShader(self.shaderObj)
 	else
-		local funcName = (debug and debug.getinfo(1).name) or "UnknownFunction"
+		local funcName = (debug and debug.getinfo and debug.getinfo(1).name) or "UnknownFunction"
 		self:ShowError(string.format("Attempt to use invalid shader object in [%s](). Did you call :Compile() or :Initialize()", funcName))
 	end
 end
@@ -959,7 +959,7 @@ function LuaShader:Activate()
 		end
 		return glUseShader(self.shaderObj)
 	else
-		local funcName = (debug and debug.getinfo(1).name) or "UnknownFunction"
+		local funcName = (debug and debug.getinfo and debug.getinfo(1).name) or "UnknownFunction"
 		self:ShowError(string.format("Attempt to use invalid shader object in [%s](). Did you call :Compile() or :Initialize()", funcName))
 		return false
 	end
@@ -980,7 +980,7 @@ function LuaShader:ActivateWith(func, ...)
 		glActiveShader(self.shaderObj, func, ...)
 		self.active = false
 	else
-		local funcName = (debug and debug.getinfo(1).name) or "UnknownFunction"
+		local funcName = (debug and debug.getinfo and debug.getinfo(1).name) or "UnknownFunction"
 		self:ShowError(string.format("Attempt to use invalid shader object in [%s](). Did you call :Compile() or :Initialize()", funcName))
 	end
 end