Using 'then' or 'do' in string literals incorrectly causes indentation

[jnwhiteh]

How are you using the lua-language-server?

Visual Studio Code Extension (sumneko.lua)

Which OS are you using?

MacOS

What is the issue affecting?

Formatting

Expected Behaviour

local f = "We go to the house and then we go home"
print(f)

Actual Behaviour

local f = "We go to the house and then we go home"
    print(f)

Reproduction steps

Open a new file. Utilize a string literal in a statement that contains either "then" or "do" and then move to the next line or use the Reindent command.

Additional Notes

No response

Log File

file_Users_jimw_tmp.log

[tomlau10]

Interesting, but seems unrelated to LuaLS 😕 I tried to disable LuaLS extension then restart vscode, and this still behaves the same ...
I guess this is somehow related to vscode built-in auto indentation for lua language. Something like this reference: https://code.visualstudio.com/api/language-extensions/language-configuration-guide#on-enter-rules

---

Or do you mean LuaLS should add functionalities to override this settings and provide a more accurate indentation on enter?

[tomlau10]

With more searching, it seems there is already an issue on vscode repo: microsoft/vscode#199223

By looking into vscode's built-in lua language extension:
https://github.com/microsoft/vscode/blob/1c7fa5ef1e67c86302bdd432da48ffe91b8c4d52/extensions/lua/language-configuration.json#L25-L28

	"indentationRules": {
		"increaseIndentPattern": "^((?!(\\-\\-)).)*((\\b(else|function|then|do|repeat)\\b((?!\\b(end|until)\\b).)*)|(\\{\\s*))$",
		"decreaseIndentPattern": "^\\s*((\\b(elseif|else|end|until)\\b)|(\\})|(\\)))"
	}

It seems to just match keywords at word boundary, ignoring the fact they may be just a word in string literal 😕

---

The current regex just states that if there exists matched keywords, and not followed by end / until, then it will be indented next line. With this fact, we can craft another false negative example (expected to have indent, but no in actual result)

if true then -- end of line
|<<< cursor here no indent...

=> that's because the word end is matched after the then, even though end is part of a comment 😇

[jnwhiteh]

Oof, worse than I thought. Thank you for helping to diagnose! I'll follow the report against vscode and think about using comments to mitigate in the meantime.

[tomlau10]

I've been working on improving the increaseIndentPattern and got some progress. And I've posted my current solution in the issue linked above. Maybe @jnwhiteh you would like to give some comments on it or even give it a try (by modifying the extensions/lua/language-configuration.json in your local vscode) 👀

I will soon open a PR for it in the vscode repo after more discussion and testing 😄