LSP: Add --lsp-port as a command line argument

[ryanabx]

Per discussion in godotengine/godot-vscode-plugin#488, and the suggestion by @Calinou in godotengine/godot-vscode-plugin#488 (comment).

Implements an --lsp-port command line argument for Godot. This argument overrides the user's editor setting for network/language_server/remote_port.

The use case for this argument would be for the godot-vscode-plugin to be able to specify the port used for the language server instance spun up by the plugin.

This would potentially solve a few long standing issues with the godot-vscode-plugin, including:

1. Godot's 3.x LSP port and 4.x LSP port don't match, causing the plugin to have to tell users to explicitly specify the port they have selected in their editor settings. (See Default LSP server port of plugin doesn't match with default port of Godot 4  godot-vscode-plugin#473)
2. Spinning up multiple workspaces in vscode would cause both to use the same language server.

If the change is accepted, it should be cherry picked to 3.x. I can help with that if need be.

Let me know what things I have to change. Since this is my first time working with main.cpp and further with #ifdef and #ifndef, please pay attention to my use of those and let me know if they are up to standard.

I also added the port to the language server editor print that says --- GDScript language server started ---, changing it to --- GDScript language server started on port "port"---.

If there are places I need to document this change at, let me know as well. :)

[DaelonSuzuka]

Just to add some context on the ramifications of this, I expect it be a significant quality-of-life improvement for everybody using VSCode and for many users of other external editors.

• This will improve the new user experience considerably. A very commonly raised issue is users not understanding that the Godot editor needs to be running for many of the extension features to work.
• This will allow us to sidestep the port number issue by launching our own LSP process.
• This is will let us do something that I believe is impossible today: opening two Godot projects in two VSCode windows and getting the correct LSP results in both of them.
• This will improve the overall stability of the editing experience, because crashes in the LSP won't kill the user's open editor.

[akien-mga]

Makes sense to me. Maybe it should simply be named --lsp-port? It's implicit for any command line option that it takes precedence over what's the current default.

[anvilfolk]

Do we think that instead of --lsp-port-override it might just be --lsp-port instead? It isn't so much an override as it's specifying a thing that otherwise has a default value, and gets rid of some extra bit of typing :)

[ryanabx]

Makes sense to me. Maybe it should simply be named --lsp-port? It's implicit for any command line option that it takes precedence over what's the current default.

Do we think that instead of --lsp-port-override it might just be --lsp-port instead? It isn't so much an override as it's specifying a thing that otherwise has a default value, and gets rid of some extra bit of typing :)

Yep, I like that better. I've changed it in the latest commit!

[ryanabx]

Other than potentially gathering more reviews, the PR is ready to go!

[adamscott]

Seems fine!

[akien-mga]

Thanks!

[van800]

I have encountered a complication with this feature. It seems to depend on the order of arguments.
This would work:
/Applications/Godot_mono_4.3dev1.app/Contents/MacOS/Godot --lsp-port 6010 --path /Users/user/Godot43vdev1 --editor
And this would not:
/Applications/Godot_mono_4.3dev1.app/Contents/MacOS/Godot --path /Users/user/Godot43vdev1 --editor --lsp-port=6010

[akien-mga]

@van800 The difference seems to be that you use --lsp-port=6010 (with =) in the second one. Godot doesn't support this format for passing argument values, it expects the value to be the next word.

[van800]

Thank you so much!