Start java process lazy / if necessary

[hirschsn]

Every new vscode window starts a java process, even if the window is empty or the project does not contain any latex files.

Optimal behaviour: Java-Process starts not until a latex file is opened.

[valentjn]

I think the fact that a new LS is opened for every VS Code window is by design, as it's supposed to work in a multi-user, multi-window (other workspaces can have different extension settings), and multi-editor (other editors can connect to the LS, too) environment. So this would be an upstream issue of the LSP specs or VS Code.

It should, however, not be necessary to have a server if there's no LaTeX file (or none of the supported file types) currently opened. The activationEvents in package.json control when the whole extension is activated. If I open a new VS Code window with a workspace where only a file of some unrelated type (MATLAB) is opened, the extension is still activated. I see this in Output -> Log (Extension Host):

ExtensionService#_doActivateExtension valentjn.vscode-ltex {"startup":false,"activationEvent":"onLanguage:plaintext"}

If I remove onLanguage:plaintext from the activationEvents, the extension is not loaded (you can test it too in .vscode/extensions/.../package.json). So this seems like a bug in VS Code to me.

[valentjn]

See upstream issue for more info: microsoft/vscode#80268

[valentjn]

Bug has been confirmed upstream. Seems plaintext is used as a fallback if the language mode cannot be detected.

[valentjn]

Now that I think about it... Most people don't want to check plaintext documents anyway, as an untitled plaintext file can just be some copy/pasted code, data, etc. I could imagine there would be lots of errors for these types of files.

plaintext doesn't necessarily mean "text in some natural language that can be spellchecked," but rather "file with arbitrary text (= not a binary file) that can't be classified as a specific known file type."

So we'll just remove the onLanguage:plaintext activation event. People will still be able to check text files if they switch the language to markdown.