Add ability to filter rules for generate-docs subcommand (realm#4195)

Added rules filtering options, like in the `rules` subcommand.

<img width="880" alt="generate-docs--help" src="https://user-images.githubusercontent.com/7829589/189372666-2f5aba62-57a1-49dc-9155-c60f9e085984.png">

To achieve reuse with `rules` subcommand:
- extracted filtering logic into `RulesFilter` (and write tests)
- extracted filtering command line parameters into `RulesFilterOptions: ParsableArguments`

BUILD

@@ -31,8 +31,9 @@ swift_library(
     }),
 )
 
-swift_binary(
-    name = "swiftlint",
+swift_library(
+    name = "swiftlint.library",
+    module_name = "swiftlint",
     srcs = glob(["Source/swiftlint/**/*.swift"]),
     visibility = ["//visibility:public"],
     deps = [
@@ -43,6 +44,14 @@ swift_binary(
     ],
 )
 
+swift_binary(
+    name = "swiftlint",
+    visibility = ["//visibility:public"],
+    deps = [
+        ":swiftlint.library",
+    ],
+)
+
 # Linting
 
 filegroup(

CHANGELOG.md

@@ -32,6 +32,9 @@
   [JP Simard](https://github.com/jpims)
   [#4031](https://github.com/realm/SwiftLint/issues/4031)
 
+* Add ability to filter rules for `generate-docs` subcommand.  
+  [kattouf](https://github.com/kattouf)
+
 * Add new `excludes_trivial_init` configuration for `missing_docs` rule
   to exclude initializers without any parameters.  
   [Marcelo Fabri](https://github.com/marcelofabri)

Package.swift

@@ -41,6 +41,12 @@ let package = Package(
                 "SwiftyTextTable",
             ]
         ),
+        .testTarget(
+            name: "CLITests",
+            dependencies: [
+                "swiftlint"
+            ]
+        ),
         .target(
             name: "SwiftLintFramework",
             dependencies: frameworkDependencies

Source/swiftlint/Commands/Common/RulesFilter.ExcludingOptions+RulesFilterOptions.swift

@@ -0,0 +1,20 @@
+extension RulesFilter.ExcludingOptions {
+    static func excludingOptions(byCommandLineOptions rulesFilterOptions: RulesFilterOptions) -> Self {
+        var excludingOptions: Self = []
+
+        switch rulesFilterOptions.ruleEnablement {
+        case .enabled:
+            excludingOptions.insert(.disabled)
+        case .disabled:
+            excludingOptions.insert(.enabled)
+        case .none:
+            break
+        }
+
+        if rulesFilterOptions.correctable {
+            excludingOptions.insert(.uncorrectable)
+        }
+
+        return excludingOptions
+    }
+}

Source/swiftlint/Commands/Common/RulesFilterOptions.swift

@@ -0,0 +1,20 @@
+import ArgumentParser
+
+enum RuleEnablementOptions: String, EnumerableFlag {
+    case enabled, disabled
+
+    static func name(for value: RuleEnablementOptions) -> NameSpecification {
+        return .shortAndLong
+    }
+
+    static func help(for value: RuleEnablementOptions) -> ArgumentHelp? {
+        return "Only show \(value.rawValue) rules"
+    }
+}
+
+struct RulesFilterOptions: ParsableArguments {
+    @Flag(exclusivity: .exclusive)
+    var ruleEnablement: RuleEnablementOptions?
+    @Flag(name: .shortAndLong, help: "Only display correctable rules")
+    var correctable = false
+}

Source/swiftlint/Commands/GenerateDocs.swift

@@ -4,13 +4,22 @@ import SwiftLintFramework
 
 extension SwiftLint {
     struct GenerateDocs: ParsableCommand {
-        static let configuration = CommandConfiguration(abstract: "Generates markdown documentation for all rules")
+        static let configuration = CommandConfiguration(
+            abstract: "Generates markdown documentation for selected group of rules"
+        )
 
         @Option(help: "The directory where the documentation should be saved")
         var path = "rule_docs"
+        @Option(help: "The path to a SwiftLint configuration file")
+        var config: String?
+        @OptionGroup var rulesFilterOptions: RulesFilterOptions
 
         func run() throws {
-            try RuleListDocumentation(primaryRuleList)
+            let configuration = Configuration(configurationFiles: [config].compactMap({ $0 }))
+            let rulesFilter = RulesFilter(enabledRules: configuration.rules)
+            let rules = rulesFilter.getRules(excluding: .excludingOptions(byCommandLineOptions: rulesFilterOptions))
+
+            try RuleListDocumentation(rules)
                 .write(to: URL(fileURLWithPath: path, isDirectory: true))
             ExitHelper.successfullyExit()
         }

Source/swiftlint/Commands/Rules.swift

@@ -10,28 +10,13 @@ import Foundation
 import SwiftLintFramework
 import SwiftyTextTable
 
-enum RuleEnablementOptions: String, EnumerableFlag {
-    case enabled, disabled
-
-    static func name(for value: RuleEnablementOptions) -> NameSpecification {
-        return .shortAndLong
-    }
-
-    static func help(for value: RuleEnablementOptions) -> ArgumentHelp? {
-        return "Only show \(value.rawValue) rules"
-    }
-}
-
 extension SwiftLint {
     struct Rules: ParsableCommand {
         static let configuration = CommandConfiguration(abstract: "Display the list of rules and their identifiers")
 
         @Option(help: "The path to a SwiftLint configuration file")
         var config: String?
-        @Flag(exclusivity: .exclusive)
-        var ruleEnablement: RuleEnablementOptions?
-        @Flag(name: .shortAndLong, help: "Only display correctable rules")
-        var correctable = false
+        @OptionGroup var rulesFilterOptions: RulesFilterOptions
         @Flag(name: .shortAndLong, help: "Display full configuration details")
         var verbose = false
         @Argument(help: "The rule identifier to display description for")
@@ -48,35 +33,12 @@ extension SwiftLint {
             }
 
             let configuration = Configuration(configurationFiles: [config].compactMap({ $0 }))
-            let rules = ruleList(configuration: configuration)
+            let rulesFilter = RulesFilter(enabledRules: configuration.rules)
+            let rules = rulesFilter.getRules(excluding: .excludingOptions(byCommandLineOptions: rulesFilterOptions))
             let table = TextTable(ruleList: rules, configuration: configuration, verbose: verbose)
             print(table.render())
             ExitHelper.successfullyExit()
         }
-
-        private func ruleList(configuration: Configuration) -> RuleList {
-            guard ruleEnablement != nil || correctable else {
-                return primaryRuleList
-            }
-
-            let filtered: [Rule.Type] = primaryRuleList.list.compactMap { ruleID, ruleType in
-                let configuredRule = configuration.rules.first { rule in
-                    return type(of: rule).description.identifier == ruleID
-                }
-
-                if ruleEnablement == .enabled && configuredRule == nil {
-                    return nil
-                } else if ruleEnablement == .disabled && configuredRule != nil {
-                    return nil
-                } else if correctable && !(configuredRule is CorrectableRule) {
-                    return nil
-                }
-
-                return ruleType
-            }
-
-            return RuleList(rules: filtered)
-        }
     }
 }
 

Source/swiftlint/Helpers/RulesFilter.swift

@@ -0,0 +1,48 @@
+import SwiftLintFramework
+
+extension RulesFilter {
+    struct ExcludingOptions: OptionSet {
+        let rawValue: Int
+
+        static let enabled = ExcludingOptions(rawValue: 1 << 0)
+        static let disabled = ExcludingOptions(rawValue: 1 << 1)
+        static let uncorrectable = ExcludingOptions(rawValue: 1 << 2)
+    }
+}
+
+class RulesFilter {
+    private let allRules: RuleList
+    private let enabledRules: [Rule]
+
+    init(allRules: RuleList = primaryRuleList, enabledRules: [Rule]) {
+        self.allRules = allRules
+        self.enabledRules = enabledRules
+    }
+
+    func getRules(excluding excludingOptions: ExcludingOptions) -> RuleList {
+        if excludingOptions.isEmpty {
+            return allRules
+        }
+
+        let filtered: [Rule.Type] = allRules.list.compactMap { ruleID, ruleType in
+            let enabledRule = enabledRules.first { rule in
+                type(of: rule).description.identifier == ruleID
+            }
+            let isRuleEnabled = enabledRule != nil
+
+            if excludingOptions.contains(.enabled) && isRuleEnabled {
+                return nil
+            }
+            if excludingOptions.contains(.disabled) && !isRuleEnabled {
+                return nil
+            }
+            if excludingOptions.contains(.uncorrectable) && !(ruleType is CorrectableRule.Type) {
+                return nil
+            }
+
+            return ruleType
+        }
+
+        return RuleList(rules: filtered)
+    }
+}

Tests/BUILD

@@ -2,6 +2,22 @@ load("@build_bazel_rules_swift//swift:swift.bzl", "swift_library", "swift_test")
 
 exports_files(["BUILD"])
 
+swift_library(
+    name = "CLITests.library",
+    testonly = True,
+    srcs = glob(["CLITests/**/*.swift"]),
+    module_name = "CLITests",
+    deps = [
+        "//:swiftlint.library",
+    ],
+)
+
+swift_test(
+    name = "CLITests",
+    visibility = ["//visibility:public"],
+    deps = [":CLITests.library"],
+)
+
 filegroup(
     name = "SwiftLintFrameworkTestsSources",
     srcs = glob(