derive attribute is not wrapped if it's exactly max length

[Dzordzu]

Tested configuration

The default one plus cargo +nightly fmt -- --unstable-features --config error_on_line_overflow=true --config imports_granularity=module

Current situation

error[internal]: line formatted, but exceeded maximum width (maximum: 100 (see `max_width` option), found: 101)
  --> /home/dzordzu/400G/work/wcss/service-user-synchro/lib/sus-protocol/src/lib.rs:58:58:101
   |
58 |     Serialize, Deserialize, Debug, Clone, EnumString, EnumIter, strum_macros::Display, PartialEq, Eq,
   |                                                                                                     ^
   |

Suggestion

Add a new option to the merge_derives that will split derives on line overflow

[ytmimi]

@Dzordzu Thanks for reaching out.

Without a minimal reproducible code snippet that we can use to reproduce the issue there's not action that the rustfmt team can take. When you have a moment can you update the description and provide a code snippet, thanks.

[Dzordzu]

Here you go!

Wrong snippet. This code is working

#[derive(
    Serialize, Deserialize, Debug, Clone, EnumString, EnumIter, strum_macros::Display, PartialEq, Eq, JsonSchema, ValueEnum
)]
#[serde(rename_all = "snake_case")]
pub enum Action {
    Create,
    Update,
    Delete,
    Undefined,
}

[ytmimi]

@Dzordzu thanks for following up.

What version of rustfmt are you using?

When running rustfmt 1.5.2-nightly (2d0aa576 2023-06-18) on your input snippet I'm unable to reproduce the internal error that you posted. I get the following formatting.

#[derive(
    Serialize,
    Deserialize,
    Debug,
    Clone,
    EnumString,
    EnumIter,
    strum_macros::Display,
    PartialEq,
    Eq,
    JsonSchema,
    ValueEnum,
)]
#[serde(rename_all = "snake_case")]
pub enum Action {
    Create,
    Update,
    Delete,
    Undefined,
}

[Dzordzu]

Hm. Strange. After update it works. Sorry for wasting your time

[Dzordzu]

UPDATED: Copied wrong snippet

#[derive(
    Serialize, Deserialize, Debug, Clone, EnumString, EnumIter, strum_macros::Display, PartialEq, Eq,
)]
#[serde(rename_all = "snake_case")]
pub enum Action {
    Create,
    Update,
    Delete,
    Undefined,
}

Fails with:

• cargo +nightly fmt -- --config error_on_line_overflow=true
• rustfmt --config error_on_line_overflow=true ./src/long.rs

Spec:

• rustfmt 1.5.2-stable (90c5418 2023-05-31)
• rustfmt 1.5.3-nightly (8084f39 2023-06-25)

Preview:

[ytmimi]

@Dzordzu I'm unable to reproduce the described behavior with the new snippet either. Can you confirm what version of rustfmt you're using and enumerate any non default configs you might be using. rustfmt should be wrapping those derives. I know you mentioned running cargo fmt.

Can you reproduce the issue when running rustfmt path/to/file.rs directly?

[Dzordzu]

@ytmimi updated the previous reply. I must have had copied the wrong snippet