From 994006585be6850b250b21aac76a58f1324cad5d Mon Sep 17 00:00:00 2001 From: Aleksey Kladov Date: Tue, 2 Jun 2020 11:16:49 +0200 Subject: Start documenting review process --- docs/dev/README.md | 105 ++++++++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 104 insertions(+), 1 deletion(-) diff --git a/docs/dev/README.md b/docs/dev/README.md index 65cc9fc12..1de5a2aab 100644 --- a/docs/dev/README.md +++ b/docs/dev/README.md @@ -30,7 +30,7 @@ https://rust-lang.zulipchat.com/#narrow/stream/185405-t-compiler.2Fwg-rls-2.2E0 * [good-first-issue](https://github.com/rust-analyzer/rust-analyzer/labels/good%20first%20issue) are good issues to get into the project. -* [E-mentor](https://github.com/rust-analyzer/rust-analyzer/issues?q=is%3Aopen+is%3Aissue+label%3AE-mentor) +* [E-has-instructions](https://github.com/rust-analyzer/rust-analyzer/issues?q=is%3Aopen+is%3Aissue+label%3AE-has-instructions) issues have links to the code in question and tests. * [E-easy](https://github.com/rust-analyzer/rust-analyzer/issues?q=is%3Aopen+is%3Aissue+label%3AE-easy), [E-medium](https://github.com/rust-analyzer/rust-analyzer/issues?q=is%3Aopen+is%3Aissue+label%3AE-medium), @@ -117,6 +117,109 @@ Additionally, I use `cargo run --release -p rust-analyzer -- analysis-stats path/to/some/rust/crate` to run a batch analysis. This is primarily useful for performance optimizations, or for bug minimization. +# Code Style & Review Process + +Our approach to "clean code" is two fold: + +* We generally don't block PRs on style changes. +* At the same time, all code in rust-analyzer is constantly refactored. + +It is explicitly OK for reviewer to flag only some nits in the PR, and than send a follow up cleanup PR for things which are easier to explain by example, cc-ing the original author. +Sending small cleanup PRs (like rename a single local variable) is encouraged. + +## Scale of Changes + +Everyone knows that it's better to send small & focused pull requests. +The problem is, sometimes you *have* to, eg, rewrite the whole compiler, and that just doesn't fit into a set of isolated PRs. + +The main thing too keep an eye on is the boundaries between various components. +There are three kinds of changes: + +1. Internals of a single component are changed. + Specifically, you don't change any `pub` items. + A good example here would be an addition of a new assist. + +2. API of a component is expanded. + Specifically, you add a new `pub` function which wasn't there before. + A good example here would be expansion of assist API, for example, to implement lazy assists or assists groups. + +3. A new dependency between components is introduced. + Specifically, you add a `pub use` reexport from another crate or you add a new line to `[dependencies]` section of `Cargo.toml`. + A good example here would be adding reference search capability to the assists crates. + +For the first group, the change is generally merged as long as: + +* it works for the happy case, +* it has tests, +* it doesn't panic for unhappy case. + +For the second group, the change would be subjected to quite a bit of scrutiny and iteration. +The new API needs to be right (or at least easy to change later). +The actual implementation doesn't matter that much. +It's very important to minimize the amount of changed lines of code for changes of the second kind. +Often, you start doing change of the first kind, only to realise that you need to elevate to a change of the second kind. +In this case, we'll probably ask you to split API changes into a separate PR. + +Changes of the third group should be pretty rare, so we don't specify any specific process for them. +That said, adding an innocent-looking `pub use` is a very simple way to break encapsulation, keep an eye on it! + +Note: if you enjoyed this abstract hand-waving about boundaries, you might appreciate +https://www.tedinski.com/2018/02/06/system-boundaries.html + +## Order of Imports + +We separate import groups with blank lines + +``` +mod x; +mod y; + +use std::{ ... } + +use crate_foo::{ ... } +use crate_bar::{ ... } + +use crate::{} + +use super::{} // but prefer `use crate::` +``` + +## Order of Items + +Optimize for the reader who sees the file for the first time, and wants to get the general idea about what's going on. +People read things from top to bottom, so place most important things first. + +Specifically, if all items except one are private, always put the non-private item on top. + +Put `struct`s and `enum`s first, functions and impls last. + +Do + +``` +// Good +struct Foo { + bars: Vec +} + +struct Bar; +``` + +rather than + +``` +// Not as good +struct Bar; + +struct Foo { + bars: Vec +} +``` + +## Documentation + +For `.md` and `.adoc` files, prefer a sentence-per-line format, don't wrap lines. +If the line is too long, you want to split the sentence in two :-) + # Logging Logging is done by both rust-analyzer and VS Code, so it might be tricky to -- cgit v1.2.3