SwiftLint/Source/SwiftLintFramework/Rules/Style/EmptyEnumArgumentsRule.swift

126 lines
4.9 KiB
Swift

import Foundation
import SourceKittenFramework
private func wrapInSwitch(variable: String = "foo", _ str: String) -> String {
return "switch \(variable) {\n" +
" \(str): break\n" +
"}"
}
private func wrapInFunc(_ str: String) -> String {
return """
func example(foo: Foo) {
switch foo {
case \(str):
break
}
}
"""
}
public struct EmptyEnumArgumentsRule: SubstitutionCorrectableASTRule, ConfigurationProviderRule, AutomaticTestableRule {
public var configuration = SeverityConfiguration(.warning)
public init() {}
public static let description = RuleDescription(
identifier: "empty_enum_arguments",
name: "Empty Enum Arguments",
description: "Arguments can be omitted when matching enums with associated types if they are not used.",
kind: .style,
nonTriggeringExamples: [
wrapInSwitch("case .bar"),
wrapInSwitch("case .bar(let x)"),
wrapInSwitch("case let .bar(x)"),
wrapInSwitch(variable: "(foo, bar)", "case (_, _)"),
wrapInSwitch("case \"bar\".uppercased()"),
wrapInSwitch(variable: "(foo, bar)", "case (_, _) where !something"),
wrapInSwitch("case (let f as () -> String)?"),
wrapInSwitch("default")
],
triggeringExamples: [
wrapInSwitch("case .bar↓(_)"),
wrapInSwitch("case .bar↓()"),
wrapInSwitch("case .bar↓(_), .bar2↓(_)"),
wrapInSwitch("case .bar↓() where method() > 2"),
wrapInFunc("case .bar↓(_)")
],
corrections: [
wrapInSwitch("case .bar↓(_)"): wrapInSwitch("case .bar"),
wrapInSwitch("case .bar↓()"): wrapInSwitch("case .bar"),
wrapInSwitch("case .bar↓(_), .bar2↓(_)"): wrapInSwitch("case .bar, .bar2"),
wrapInSwitch("case .bar↓() where method() > 2"): wrapInSwitch("case .bar where method() > 2"),
wrapInFunc("case .bar↓(_)"): wrapInFunc("case .bar")
]
)
public func validate(file: SwiftLintFile, kind: StatementKind,
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))
}
}
public func substitution(for violationRange: NSRange, in file: SwiftLintFile) -> (NSRange, String)? {
return (violationRange, "")
}
public func violationRanges(in file: SwiftLintFile, kind: StatementKind,
dictionary: SourceKittenDictionary) -> [NSRange] {
guard kind == .case else {
return []
}
let contents = file.stringView
let callsRanges = dictionary.substructure.compactMap { dict -> NSRange? in
guard dict.expressionKind == .call,
let byteRange = dict.byteRange,
let range = contents.byteRangeToNSRange(byteRange)
else {
return nil
}
return range
}
return dictionary.elements.flatMap { subDictionary -> [NSRange] in
guard subDictionary.kind == "source.lang.swift.structure.elem.pattern",
let byteRange = subDictionary.byteRange,
let caseRange = contents.byteRangeToNSRange(byteRange)
else {
return []
}
let emptyArgumentRegex = regex("\\.\\S+\\s*(\\([,\\s_]*\\))")
return emptyArgumentRegex.matches(in: file.contents, options: [], range: caseRange).compactMap { match in
let parenthesesRange = match.range(at: 1)
// avoid matches after `where` keyworkd
if let whereRange = file.match(pattern: "where", with: [.keyword], range: caseRange).first {
if whereRange.location < parenthesesRange.location {
return nil
}
// avoid matches in "(_, _) where"
if let whereByteRange = contents.NSRangeToByteRange(start: whereRange.location,
length: whereRange.length),
case let length = whereByteRange.location - byteRange.location,
case let byteRange = ByteRange(location: byteRange.location, length: length),
Set(file.syntaxMap.kinds(inByteRange: byteRange)) == [.keyword] {
return nil
}
}
if callsRanges.contains(where: parenthesesRange.intersects) {
return nil
}
return parenthesesRange
}
}
}
}