Comments with /* */ have whitespace issues when formatting

[brandonsurh]

This was discovered during the progress of #5297.

So it seems that formatting comments such as /* inline test */ is a little finnicky within swayfmt. The comments seem to get shifted around in various ways depending on the category that they are identified as. This issue persists across all the items I have tested so far.

It is possible that the whitespace formatting I see is desired, though I wouldn't expect it to be as the items treat the same comments differently.

Useful commit to pull for testing here.

Example:

Behavior for item_abi and item_impl:
Before:

script;

use std::{constants::ZERO_B256, vm::evm::evm_address::EvmAddress};

abi MyContract {
    // double slash comment
    /// triple slash comment
    /* inline comment */
    /*
        multiline comment
    */
    fn test_function() -> bool;
}

impl MyContract for Contract {
    // double slash comment
    /// triple slash comment
    /* inline comment */
    /*
        multiline comment
    */

    fn test_function() -> bool {
        true
    }
}

After:

script;

use std::{constants::ZERO_B256, vm::evm::evm_address::EvmAddress};

abi MyContract {
    // double slash comment
    /// triple slash comment /* inline comment */
    /*
        multiline comment
    */
    fn test_function() -> bool;
}

impl MyContract for Contract {
    // double slash comment
    /// triple slash comment /* inline comment */
    /*
        multiline comment
    */
    fn test_function() -> bool {
        true
    }
}

Behavior for item_enum and item_configurable:
Before:

enum Color {
    // double slash comment
    /// triple slash comment
    /* inline comment */
    /*
        multiline comment
    */
    blue: (),
    red: ()
}

configurable {
    // double slash comment
    /// triple slash comment
    /* inline comment */
    /*
        multiline comment
    */
    SIGNER: EvmAddress = EvmAddress {
        value: ZERO_B256,
    },
}

After:

enum Color {
    // double slash comment
    /// triple slash comment
/* inline comment */    /*
        multiline comment
    */    blue: (),
    red: (),
}

configurable {
    // double slash comment
    /// triple slash comment
/* inline comment */    /*
        multiline comment
    */    SIGNER: EvmAddress = EvmAddress {
        value: ZERO_B256,
    },
}

The implementation for item_enum and item_configurable are the same. I'm assuming this is why they have the same behavior.

Also, if I try to place the same comments inside of fn test_function() then the test fails with:

running 1 test
thread 'configurable_comments' panicked at 'called `Result::unwrap()` on an `Err` value: ParseFileError(ParseFileError([Parse { error: ParseError { span: Span { src (ptr): 0x7f929c002290, source_id: None, start: 478, end: 502, as_str(): "/// triple slash comment" }, kind: ExpectedExpression } }]))', swayfmt/tests/mod.rs:8:86
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
test configurable_comments ... FAILED

failures:

failures:
    configurable_comments

This is possibly a duplicate as we fix formatting issues regarding comments, but I couldn't find anything about this in particular.

[sdankel]

Thanks for digging in! How does this behavior compare to cargo fmt's handling of comments?

[brandonsurh]

Just did some testing and those whitespace changes don't exist with cargo fmt. At least not when formatting enum and impl blocks. To save you the trouble, the before and after blocks below are exactly the same.

Before:

enum IpAddrKind {
    // double slash comment
    /// triple slash comment
    /* inline comment */
    /*
        multiline comment
    */
    V4,
    V6,
}

impl Rectangle {
    // double slash comment
    /// triple slash comment
    /* inline comment */
    /*
        multiline comment
    */
    fn test(&self) -> u32 {
        // double slash comment
        /// triple slash comment
        /* inline comment */
        /*
            multiline comment
        */
        10
    }
}

fn main() {}

After:

enum IpAddrKind {
    // double slash comment
    /// triple slash comment
    /* inline comment */
    /*
        multiline comment
    */
    V4,
    V6,
}

impl Rectangle {
    // double slash comment
    /// triple slash comment
    /* inline comment */
    /*
        multiline comment
    */
    fn test(&self) -> u32 {
        // double slash comment
        /// triple slash comment
        /* inline comment */
        /*
            multiline comment
        */
        10
    }
}

fn main() {}