472
rust blasphemy (added context)
(lemmy.world)
made in gimp, with <3
Context for actual rust programmers
I was having massive beef with the rust compiler yesterday, every cargo check takes 20 seconds.
And then look at the three functions below, only one of them are Send, if you know why, please let me know.
(Note: value that is not Send cannot be held across an await point, and Box is not Send)
async fn one() {
let res: Result<(), Box<dyn Error>> = do_stuff();
if let Err(err) = res {
let content = err.to_string();
let _ = do_stuff(content).await;
}
}
async fn two() {
let res: Result<(), Box<dyn Error>> = do_stuff();
let content = if let Err(err) = res {
Some(err.to_string())
} else {
None
};
drop(res);
if let Some(content) = content {
let _ = do_stuff(content).await;
}
}
async fn three() {
let content = {
let res: Result<(), Box<dyn Error>> = do_stuff();
if let Err(err) = res {
Some(err.to_string())
} else {
None
}
};
if let Some(content) = content {
let _ = do_stuff(content).await;
}
}
I think we're doing different things, that's why it's giving us completely different errors.
I just added files to imports in configuration.nix
I'm guessing you've got some manual error checking implemented with assertions?
I'm yet to see any nix error be more readable top to bottom. And I think it's intentionally designed that way so you don't need to scroll up.
I don't think, we are doing different things. I create a new file, put
{}inside, then add it into theimports = [...];. It gives me that error.Then I
git add ., run again and don't get the error anymore.Is the error you pasted now from some manual assertion you did?
Yeah I'm doing the same, I even tried to import a nonexistent file, and use build like you instead of switch, but I'm only getting the error from above.
What's your nix version?
nix (Nix) 2.34.6
Hmm, for whatever reason, I'm on 2.31.4, so that might be the difference.
That version was tagged two weeks ago, because they apparently still release patch versions for rather old minor versions of
nix. So, apparently I am getting updates, but I'm on some older release channel or something. No idea why.I have to head to work now, so will have to debug in the evening or the weekend. Thanks for the clue, though.