JP Simard c0f9f2175b Add support for native custom rules (#4039) ...

This change makes it possible to add native custom rules when building
SwiftLint via Bazel (possible as of
https://github.com/realm/SwiftLint/pull/4038).

First, add a local bazel repository where custom rules will be defined
to your project's `WORKSPACE`:

```python
local_repository(
    name = "swiftlint_extra_rules",
    path = "swiftlint_extra_rules",
)
```

Then in the extra rules directory, add an empty `WORKSPACE` and a
`BUILD` file with the following contents:

```python
filegroup(
    name = "extra_rules",
    srcs = glob(["*.swift"]),
    visibility = ["//visibility:public"],
)
```

To add a rule (for example, `MyPrivateRule`) add the following two
files:

```swift
// ExtraRules.swift
func extraRules() -> [Rule.Type] {
    [
        MyPrivateRule.self,
    ]
}
```

```swift
// MyPrivateRule.swift
import SourceKittenFramework
import SwiftSyntax

struct MyPrivateRule: ConfigurationProviderRule {
    var configuration = SeverityConfiguration(.error)

    init() {}

    static let description = RuleDescription(
        identifier: "my_private_rule",
        name: "My Private Rule",
        description: "This is my private rule.",
        kind: .idiomatic
    )

    func validate(file: SwiftLintFile) -> [StyleViolation] {
        // Perform validation here...
    }
}
```

Then you can reference the rule in your configuration or source files as
though they were built in to the official SwiftLint repo.

This means that you have access to SwiftLintFramework's internal API.
We make no guarantees as to the stability of these internal APIs,
although if you end up using something that gets removed please reach
out and we'll make a best effort to maintain some level of support.

This PR also improves the linter cache on macOS to make it correctly
invalidate previous results when custom native rules are edited. This
even works when doing local development of SwiftLint, where previous it
was necessary to use `--no-cache` when working on SwiftLint, now the
cache should always work.

Co-authored-by: Keith Smiley <keithbsmiley@gmail.com>

2022-07-26 13:56:22 -04:00

..

ExtraRules.swift

Add support for native custom rules (#4039)

2022-07-26 13:56:22 -04:00