feat: TOML based config for rust-analyzer
> Important
>
> We don't promise _**any**_ stability with this feature yet, any configs exposed may be removed again, the grouping may change etc.
# TOML Based Config for RA
This PR ( addresses #13529 and this is a follow-up PR on #16639 ) makes rust-analyzer configurable by configuration files called `rust-analyzer.toml`. Files **must** be named `rust-analyzer.toml`. There is not a strict rule regarding where the files should be placed, but it is recommended to put them near a file that triggers server to start (i.e., `Cargo.{toml,lock}`, `rust-project.json`).
## Configuration Types
Previous configuration keys are now split into three different classes.
1. Client keys: These keys only make sense when set by the client (e.g., by setting them in `settings.json` in VSCode). They are but a small portion of this list. One such example is `rust_analyzer.files_watcher`, based on which either the client or the server will be responsible for watching for changes made to project files.
2. Global keys: These keys apply to the entire workspace and can only be set on the very top layers of the hierarchy. The next section gives instructions on which layers these are.
3. Local keys: Keys that can be changed for each crate if desired.
### How Am I Supposed To Know If A Config Is Gl/Loc/Cl ?
#17101
## Configuration Hierarchy
There are 5 levels in the configuration hierarchy. When a key is searched for, it is searched in a bottom-up depth-first fashion.
### Default Configuration
**Scope**: Global, Local, and Client
This is a hard-coded set of configurations. When a configuration key could not be found, then its default value applies.
### User configuration
**Scope**: Global, Local
If you want your configurations to apply to **every** project you have, you can do so by setting them in your `$CONFIG_DIR/rust-analyzer/rust-analyzer.toml` file, where `$CONFIG_DIR` is :
| Platform | Value | Example |
| ------- | ------------------------------------- | ---------------------------------------- |
| Linux | `$XDG_CONFIG_HOME` or `$HOME`/.config | /home/alice/.config |
| macOS | `$HOME`/Library/Application Support | /Users/Alice/Library/Application Support |
| Windows | `{FOLDERID_RoamingAppData}` | C:\Users\Alice\AppData\Roaming |
### Client configuration
**Scope**: Global, Local, and Client
Previously, the only way to configure rust-analyzer was to configure it from the settings of the Client you are using. This level corresponds to that.
> With this PR, you don't need to port anything to benefit from new features. You can continue to use your old settings as they are.
### Workspace Root Configuration
**Scope**: Global, Local
Rust-analyzer already used the path of the workspace you opened in your Client. We used this information to create a configuration file that won't affect your other projects and define global level configurations at the same time.
### Local Configuration
**Scope**: Local
You can also configure rust-analyzer on a crate level. Although it is not an error to define global ( or client ) level keys in such files, they won't be taken into consideration by the server. Defined local keys will affect the crate in which they are defined and crate's descendants. Internally, a Rust project is split into what we call `SourceRoot`s. This, although with exceptions, is equal to splitting a project into crates.
> You may choose to have more than one `rust-analyzer.toml` files within a `SourceRoot`, but among them, the one closer to the project root will be
chore: add some `tracing` to project loading
I wanted to see what's happening during project loading and if it could be parallelized. I'm thinking maybe, but it's not this PR :)
It is bitset semantically --- many categorical things can be true about
a reference at the same time.
In parciular, a reference can be a "test" and a "write" at the same
time.
internal : redesign rust-analyzer::config
This PR aims to cover the infrastructural requirements for the `rust-analyzer.toml` ( #13529 ) issue. This means, that
1. We no longer have a single config base. The once single `ConfigData` has been divided into 4 : A tree of `.ratoml` files, a set of configs coming from the client ( this is what was called before the `CrateData` except that now values do not default to anything when they are not defined) , a set of configs that will reflect what the contents of a `ratoml` file defined in user's config directory ( e.g `~/.config/rust-analyzer/.rust-analyzer.toml` and finally a tree root that is populated by default values only.
2. Configs have also been divided into 3 different blocks : `global` , `local` , `client`. The current status of a config may change until #13529 got merged.
Once again many thanks to `@cormacrelf` for doing all the serde work.
internal: Enforce utf8 paths
Cargo already requires this, and I highly doubt r-a works with non-utf8 paths generally either. This just makes dealing with paths a lot easier.
internal: Compress file text using LZ4
I haven't tested properly, but this roughly looks like:
```
1246 MB
59mb 4899 FileTextQuery
1008 MB
20mb 4899 CompressedFileTextQuery
555kb 1790 FileTextQuery
```
We might want to test on something more interesting, like `bevy`.
