rust-lang / rust-lang/rustfmt

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

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C-feature-request I-max-width P-low
Dominant language
Rust
Stars
7k
Forks
1.1k
Avg merge
2d 13h
Merged PRs (30d)
24

Description

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

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by reproducing the reported overflow with the nightly rustfmt command and configuration from the issue. Read the merge_derives documentation, then trace the existing merge_derives behavior; done means an option can split derives when the merged line reaches the configured maximum width and the overflow case is covered.

Written by the indexing model from the issue text.

Assessment

Tech stack
rust
Domain
tooling
Issue type
Feature
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

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