Lua behaviour has changed sometime since Wireshark 1.8.7

Question

I just upgraded Wireshark from 1.8.7 to the latest stable version (1.12.2) on my Windows machine.

The Lua engine now behaves differently, rendering my plugin dissectors inoperative. I have three dissectors, each in a separate .lua source file, that make use of some common, global, variables that are declared in a fourth .lua source file. All of these sources are placed in my %APPDATA%\Roaming\Wireshark\plugins directory.

After the Lua engine reads all these sources in, all non-local entities declared in any file USED TO BE ACCESSIBLE from any function subsequently run (even if that function were defined in a different source file to the entity's declaration).

Are individual .lua source files now treated as separate namespaces (effectively making all declarations local to their containing file)?

Is there some way to restore the ability to declare entities that can be visible from functions in other sources?

Thanks.

Answer 1

Yes, a long time ago the loading of plugins was changed to be scoped to a separate environment for each plugin file, to prevent clobbering of variables if people forgot to make their variables local.

To handle your use-case, I think you have two options:

In the file that declares your global variables, declare them explicitly as global variables by putting them in the global table. For example, like this:
```
 _G["myVariable1"] = true
 _G["myVariable2"] = 42
 -- or this syntax
 _G.myVariable3 = false
 _G.myVariable4 = "foobar"
```
Or, have Wireshark only load the one plugin that declares the common global variables, and in that plugin use dofile() or load file() to load all the other plugins. That way they're all loaded into the same environment.