mirrors/arti.git/crates/tor-rtcompat/src/lib.rs, branch derive-traits

Merge branch 'clippy-allow-arc-clone' into 'main'

2022-03-01T20:38:05Z

Disable clippy::clone_on_ref_ptr See merge request tpo/core/arti!352

Fix rustdoc errors.

2022-03-01T13:16:02Z

arti-client: use PreferredRuntime by default, doc cleanups

2022-02-28T16:41:13Z

This makes using the `PreferredRuntime` the first-class option inside `arti-client`, freeing users who don't want to think about runtimes from having to do so. `TorClient::create_unbootstrapped` and `builder` now automatically use this runtime, leaving only `builder_custom` for users who wish to manually specify a runtime. This lets us clean up the docs a lot: mentions of using custom runtimes are now relegated to nearer the end of the crate-level documentation, and we mostly just link to `tor_rtcompat`'s docs to explain more there. Instead, we take some more time to explain how you use the builder API to create clients synchronously. Other doc cleanups included getting rid of the explanation of `TorAddr` in the main crate-level doc; this is already well-documented elsewhere, and is something users should discover organically later. fixes arti#326

tor-rtcompat: refactor PreferredRuntime, clean up docs

2022-02-25T17:34:05Z

`PreferredRuntime` is now an opaque wrapper struct that contains the "actual" preferred runtime as a type alias. The `current_user_runtime` and `create_runtime` functions become `PreferredRuntime::current` and `PreferredRuntime::create`, respectively. This removes the dependence on `impl Trait`, meaning we can now name the returned runtime (yay!). In addition, the documentation was cleaned up a bit to make it (hopefully) flow better. Items that don't make sense to publicize, like testing implementation details, have been marked #[doc(hidden)] and semver warnings added.

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.

add example of tcp hook

2022-02-23T13:29:37Z

this required to make additional types public

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

2022-02-14T14:24:06Z

Closes #338.

tor-rtcompat: Add some miscellaneous tests

2022-01-27T20:48:30Z

These probably aren't for things that will fail IRL, but it's nice to have coverage on the code, just in case.

tor-rtcompat: Simplify test-declaration macros.

2022-01-27T20:09:09Z

Now there's much less copy-and-paste.

Move tor-rtcompat tests to lib.rs

2022-01-27T19:45:00Z

This makes our layout more similar to our other crates, and successfully informs our grcov exclusion pattern that these tests are indeed tests. Doing this knocks down the reported coverage for the tor-rtcompat crate, but that's okay: we hadn't earned it. I hereby promise that this commit is only code-movement.