mirrors/arti.git/crates/tor-units/src, branch derive-traits

Disable clippy::clone_on_ref_ptr

2022-02-24T18:15:44Z

This lint is IMO inherently ill-conceived. I have looked for the reasons why this might be thought to be a good idea and there were basically two (and they are sort of contradictory): I. "Calling ‘.clone()` on an Rc, Arc, or Weak can obscure the fact that only the pointer is being cloned, not the underlying data." This is the wording from https://rust-lang.github.io/rust-clippy/v0.0.212/#clone_on_ref_ptr It is a bit terse; we are left to infer why it is a bad idea to obscure this fact. It seems to me that if it is bad to obscure some fact, that must be because the fact is a hazard. But why would it be a hazard to not copy the underlying data ? In other languages, faliing to copy the underlying data is a serious correctness hazard. There is a whose class of bugs where things were not copied, and then mutated and/or reused in multiple places in ways that were not what the programmer intended. In my experience, this is a very common bug when writing Python and Javascript. I'm told it's common in golang too. But in Rust this bug is much much harder to write. The data inside an Arc is immutable. To have this bug you'd have use interior mutability - ie mess around with Mutex or RefCell. That provides a good barrier to these kind of accidents. II. "The reason for writing Rc::clone and Arc::clone [is] to make it clear that only the pointer is being cloned, as opposed to the underlying data. The former is always fast, while the latter can be very expensive depending on what is being cloned." This is the reasoning found here https://github.com/rust-lang/rust-clippy/issues/2048 This is saying that *not* using Arc::clone is hazardous. Specifically, that a deep clone is a performance hazard. But for this argument, the lint is precisely backwards. It's linting the "good" case and asking for it to be written in a more explicit way; while the supposedly bad case can be written conveniently. Also, many objects (in our codebase, and in all the libraries we use) that are Clone are in fact simply handles. They contain Arc(s) (or similar) and are cheap to clone. Indeed, that is the usual case. It does not make sense to distinguish in the syntax we use to clone such a handle, whether the handle is a transparent Arc, or an opaque struct containing one or more other handles. Forcing Arc::clone to be written as such makes for code churn when a type is changed from Arc to Something: Clone, or vice versa.

Change deny(clippy::all) to warn(clippy::all).

2022-02-14T14:24:06Z

Closes #338.

extend lints to include 'clippy::all'

2021-12-28T20:15:40Z

address lint warnings

2021-12-09T13:47:59Z

tor-netdir: Resolve an XXXX about type ugliness

2021-12-08T17:32:44Z

We had no function to infallibly convert BoundedInt32<{0 or 1},H> into a u32, even though we could have. Because of that, we were treating weight_scale as an i32 when logically it's a u32 or a NonZeroU32. Moreover, it turns out we were using an incorrect minimum for the bwweightscale param, which would in theory have allowed the authorities to make us divide by zero. This patch introduces the necessary From<> implementation and uses it. It corrects the binimum bwweightscale, and prevents a division-by-zero issue in case weight_scale is zero.

Get tor-units grcov line coverage to 100%

2021-12-02T22:08:22Z

This is mostly a finger exercise, and an experiment in "what does grcov consider to be coverage". Here's what I've found out... * In grcov's eyes, most #[derive(Foo)] lines count as containing code; but calling any one derived function counts as calling those lines. * Unlike with tarpaulin, it is actually possible to reach 100% grcov line coverage. (Tarpaulin likes to pick "}" lines and tell you that you never reached them; or sometimes it picks expression statements that have the effect of a return, and tells you that they're unreached. Even with these tests, tarpaulin claims that the line coverage of tor-units is only 97.3%.) * In rust, it may be a bit hopeless trying to get high function coverage. Even though we've hit every line of the tor-units crate, the function coverage from its own tests is only 9.38% (55.41% from other crates). I think this is probably due to derived functions, or maybe due to generics getting instantiated? I've got no idea; the denominator for the function coverage lines fluctuates oddly.

Implement Eq,PartialEq for BoundedInt32.

2021-12-02T21:40:22Z

add semicolons if nothing returned

2021-11-25T13:20:37Z

More typo fixes that I forgot to save :(

2021-11-24T23:23:12Z

enable checked_conversions lint.

2021-10-09T20:53:13Z