SwiftLint/Source/SwiftLintFramework/Rules/Idiomatic/ExplicitInitRule.swift

90 lines
3.9 KiB
Swift

import Foundation
import SourceKittenFramework
public struct ExplicitInitRule: SubstitutionCorrectableASTRule, ConfigurationProviderRule, OptInRule,
AutomaticTestableRule {
public var configuration = SeverityConfiguration(.warning)
public init() {}
public static let description = RuleDescription(
identifier: "explicit_init",
name: "Explicit Init",
description: "Explicitly calling .init() should be avoided.",
kind: .idiomatic,
nonTriggeringExamples: [
Example("import Foundation; class C: NSObject { override init() { super.init() }}"), // super
Example("struct S { let n: Int }; extension S { init() { self.init(n: 1) } }"), // self
Example("[1].flatMap(String.init)"), // pass init as closure
Example("[String.self].map { $0.init(1) }"), // initialize from a metatype value
Example("[String.self].map { type in type.init(1) }"), // initialize from a metatype value
Example("Observable.zip(obs1, obs2, resultSelector: MyType.init).asMaybe()"),
Example("""
Observable.zip(
obs1,
obs2,
resultSelector: MyType.init
).asMaybe()
""")
],
triggeringExamples: [
Example("[1].flatMap{String↓.init($0)}"),
Example("[String.self].map { Type in Type↓.init(1) }"), // starting with capital assumes as type,
Example("""
func foo() -> [String] {
return [1].flatMap { String↓.init($0) }
}
"""),
Example("""
Observable.zip(
obs1,
obs2,
resultSelector: { MyType.init($0, $1) }
).asMaybe()
""")
],
corrections: [
Example("[1].flatMap{String↓.init($0)}"): Example("[1].flatMap{String($0)}"),
Example("func foo() -> [String] {\n return [1].flatMap { String↓.init($0) }\n}"):
Example("func foo() -> [String] {\n return [1].flatMap { String($0) }\n}"),
Example("class C {\n#if true\nfunc f() {\n[1].flatMap{String.init($0)}\n}\n#endif\n}"):
Example("class C {\n#if true\nfunc f() {\n[1].flatMap{String($0)}\n}\n#endif\n}")
]
)
public func validate(file: SwiftLintFile, kind: SwiftExpressionKind,
dictionary: SourceKittenDictionary) -> [StyleViolation] {
return violationRanges(in: file, kind: kind, dictionary: dictionary).map {
StyleViolation(ruleDescription: type(of: self).description,
severity: configuration.severity,
location: Location(file: file, characterOffset: $0.location))
}
}
private let initializerWithType = regex("^[A-Z][^(]*\\.init$")
public func violationRanges(in file: SwiftLintFile, kind: SwiftExpressionKind,
dictionary: SourceKittenDictionary) -> [NSRange] {
func isExpected(_ name: String) -> Bool {
let range = NSRange(location: 0, length: name.utf16.count)
return !["super.init", "self.init"].contains(name)
&& initializerWithType.numberOfMatches(in: name, options: [], range: range) != 0
}
let length = ByteCount(".init".utf8.count)
guard kind == .call,
let name = dictionary.name, isExpected(name),
let nameOffset = dictionary.nameOffset,
let nameLength = dictionary.nameLength,
let range = file.stringView
.byteRangeToNSRange(ByteRange(location: nameOffset + nameLength - length, length: length))
else { return [] }
return [range]
}
public func substitution(for violationRange: NSRange, in file: SwiftLintFile) -> (NSRange, String)? {
return (violationRange, "")
}
}