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;
}
}
It's a different error. To me it looks like you tried to import a file that doesn't exist. I made the file correctly and imported it, just didn't git add it. After committing I switched without issues.
For me that error message was in the same spot. The rest of the trace is what was evaled so you got to that error. It's the same principle as stack trace in other languages.
No, unstable nixos + home-manager. The error above was from
Hmm, that sounds exactly like my setup. Weird.
I did have the file created, with
{}inside (empty Nix expression). If Igit addit, it works as well:And yeah, I understand that it's supposed to be a stacktrace, but other error messages look similarly horrendous and I can often only try to guess what's wrong by reading the stacktrace top-to-bottom, so I've somewhat gotten used to doing that.
But good to know that these terrible error messages might be a problem with my system. Thanks!
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