[Rust] PartialEq for DataFrame

[ibENPC]

New implementation

Following #1833

impl PartialEq for DataFrame {
    fn eq(&self, other: &Self) -> bool {
        self.shape() == other.shape()
            && self
                .columns
                .par_iter()
                .zip_eq(other.columns.par_iter())
                .all(|(x, y)| x == y)
    }
}

Miri issue

Miri is giving me these warning and error:

test testing::test::test_df_partialeq ... warning: thread support is experimental and incomplete: weak memory effects are not emulated.

[...]

error: the main thread terminated without waiting for all remaining threads

I assume that the problem is because the eq function is parallel and is tested at the end of the Miri check, but I don't know why it doesn't wait for all the threads to finish 😅

[ibENPC]

There is some debate about this issue:

• https://users.rust-lang.org/t/how-to-test-rayon-with-miri/67314
• Support detached threads still running when the main thread exits ("thread leaks") rust-lang/miri#1371

So I keep it simple and safe for now by not using the iterators of Rayon but the iterators of the std::iter.

impl PartialEq for DataFrame {
    fn eq(&self, other: &Self) -> bool {
        self.shape() == other.shape()
            && self
                .columns
                .iter()
                .zip(other.columns.iter())
                .all(|(s1, s2)| s1 == s2)
    }
}

[ritchie46]

Also not needed to do in parallel. So great!