Mypy Flycheck Clears Errors On Unsaved File

Question

I am currently trying to port over my python enviornment to Doom Emacs from VSCode. One of the major features I want is type checking from MyPy. Doom Emacs' flycheck comes with MyPy as an option by default so I was going to use that.

My major issue with it though is that while it correctly lints saved files, as soon as I make any edits all linting help goes away and mypy will say that there are no errors until the next time I save. It would be okay if the linting didn't re run while I was editing, but its important for me that the errors don't just disappear.

Notably, when I use other checkers, such as flake or the default lsp, there is no such issue with linting disappear.

Does anyone know how to fix this?

Answer 1

Not a Doom Emacs user, but it sounds like it might be setting flycheck-check-syntax-automatically. Disable Doom's setting or customize it yourself to include "idle-change". For instance mine is (via C-h v flycheck-check-syntax-automatically):

flycheck-check-syntax-automatically is a variable defined in ‘flycheck.el’.

Its value is (save idle-change new-line mode-enabled)

When Flycheck should check syntax automatically.

This variable is a list of events that may trigger syntax checks.
The following events are known:
...