mirrors/arti.git/crates/tor-dirmgr/src/lib.rs, 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.

dirmgr: add Store trait

2022-02-23T18:50:33Z

Merge branch 'remaining-errors'

2022-02-17T19:22:47Z

dirmgr: Remember where netdocs came from.

2022-02-16T21:28:23Z

This isn't complete (see TODO), but it's enough to let us report the right ErrorKind if something fails to parse.

arti-client: add ability to automatically bootstrap

2022-02-16T19:29:16Z

The new `BootstrapBehavior` enum controls whether an unbootstrapped `TorClient` will bootstrap itself automatically (`Ondemand`) when an attempt is made to use it, or whether the user must perform bootstrapping themselves (`Manual`). The `lazy-init` example shows how you could write a simple `get_tor_client()` function that used a global `OnceCell` to share a Tor client across an entire application with this API. closes arti#278

Merge branch 'warn_not_deny' into 'main'

2022-02-14T19:45:18Z

Change deny(clippy::all) to warn(clippy::all). Closes #338 See merge request tpo/core/arti!306

dirmgr: Remove a useless Ok(x?)

2022-02-14T14:30:18Z

Found by nightly clippy.

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

2022-02-14T14:24:06Z

Closes #338.

Allow creating unbootstrapped `TorClient`s (and `DirMgr`s)

2022-02-11T16:42:19Z

This commit changes how the `TorClient` type works, enabling it to be constructed synchronously without initiating the bootstrapping process. Daemon tasks are still started on construction (although some of them won't do anything if the client isn't bootstrapped). The old bootstrap() methods are now reimplemented in terms of the new create_unbootstrapped() and bootstrap_existing() methods. This required refactoring how the `DirMgr` works to enable the same sort of thing there. closes #293

Make SpawnError wrappers contain a 'spawning' string

2022-02-04T21:06:11Z

(By our convention, these errors should say what we were trying to spawn when the error occurred.)