error[internal]: left behind trailing whitespace

[skrobchik]

Hello 👋

I'm getting an error when running cargo fmt in my project. Here's the commit.

Not sure if you need any logs? I didn't see any guidelines for filing bug reports, so please let me know if anything is needed 😄

PS C:\Users\Robert\Desktop\Git Projects\calenda-rs> git clean -ffdx
PS C:\Users\Robert\Desktop\Git Projects\calenda-rs> git status
On branch master
Your branch is up to date with 'origin/master'.

nothing to commit, working tree clean
PS C:\Users\Robert\Desktop\Git Projects\calenda-rs> cargo fmt
error[internal]: left behind trailing whitespace
   --> \\?\C:\Users\Robert\Desktop\Git Projects\calenda-rs\crates\calendars_egui\src\class_editor.rs:132:132:1
    |
132 |
    | ^^^^
    |

error[internal]: left behind trailing whitespace
   --> \\?\C:\Users\Robert\Desktop\Git Projects\calenda-rs\crates\calendars_egui\src\class_editor.rs:145:145:1
    |
145 |
    | ^^^^
    |

warning: rustfmt has failed to format. See previous 2 errors.

PS C:\Users\Robert\Desktop\Git Projects\calenda-rs> rustfmt --version
rustfmt 1.7.0-nightly (9d5cdf75 2024-04-07)
PS C:\Users\Robert\Desktop\Git Projects\calenda-rs> rustc --version
rustc 1.79.0-nightly (9d5cdf75a 2024-04-07)
PS C:\Users\Robert\Desktop\Git Projects\calenda-rs> cargo --version
cargo 1.79.0-nightly (28e7b2bc0 2024-04-05)
PS C:\Users\Robert\Desktop\Git Projects\calenda-rs>

[ytmimi]

@skrobchik thanks for the report. When you get a chance, can you try to minimize the reproducible example to be as small as possible. Taking a look at the commit that you referenced I suspect this might be another duplicate of #3863 leading to rustfmt complaining about whitespace that exists within the source code.

[ealinye]

this error also happen in my project, while formating chain-call, like:

        let benches: Vec<_> = self[gidx]
            .res
            
            .iter()

then:

yiyue@terc ~/Pin1Yin1-Compiler-Rust (main)> rustfmt py-ast/src/semantic/declare/map.rs
error[internal]: left behind trailing whitespace
  --> /home/yiyue/Pin1Yin1-Compiler-Rust/py-ast/src/semantic/declare/map.rs:72:72:1
   |
72 |             
   | ^^^^^^^^^^^^
   |

warning: rustfmt has failed to format. See previous 1 errors.

because i always use vscode's format on save to format my code, it's hard to not notice that the code is not formated after i changed the code

although i can get error by using cli, there are not any log are printed...

[konstin]

Here's a semi minimal example (make sure your ide doesn't remove trailing whitespace by default):

impl Preferences {
    fn from_iter() -> Self {
        Self(
            preferences
                .filter_map(|preference| {
                    trace!(
                        "Excluding {} from preferences due to unmatched markers.", requirement.name
                    );
                    match requirement {
                        UvSource => {
                            if *ve {
                                trace!(
                                    "Excluding {} from preferences due to inexact version specifier.", requirement.name
                                );
                            }
                        }
                    }

                    

                })
                .collect(),
        )
    }
}

Playground: https://play.rust-lang.org/?version=stable&mode=debug&edition=2021&gist=01c66f1e423afb96d09aaebbbf5f7e33

[ytmimi]

@konstin your example is definitely a duplicate of #3863. preferences.filter_map().collect() is a chain, and there are lines that exceed the max_width.

Because of the nested nature of the code, the line with the string literal exceeds the default width of 100.

                                trace!(
                                    "Excluding {} from preferences due to inexact version specifier.", requirement.name
                                );

You have 3 options:

1. bump the max_width
2. manually break the string literal over multiple lines
3. if you're using nightly rustfmt you can try using format_strings=true

[ytmimi]

@skrobchik having just reviewed the commit it would seem that this line 👇🏼 is causing the ui.vertical(|ui| {}) call on line 60 from being formatted, therefore failing to remove whitespace that exists in the program.

              "El programa intentara asignar una aula de las categorias seleccionadas a esta clase.",

Taking a look at the file shows that there is indeed trailing whitespace in the commit:

The advice to resolve this is the same as I mentioned above, with the addition that you could refactor your code and extract your message into a constant. For example:

const HOVER_TEXT: &str = "El programa intentara asignar una aula de las categorias seleccionadas a esta clase.";

ui.label(RichText::new("Aulas Permitidas").strong()).on_hover_text(HOVER_TEXT);

[konstin]

Would it be possible to disable the trailing whitespace check if rustfmt gave up on a too long line? Rustfmt not touching a piece of the AST is fine, the current error makes it look like you discovered a bad rustfmt bug