only rule should work for individual custom rules

CHANGELOG.md

@@ -23,6 +23,14 @@
   [Martin Redington](https://github.com/mildm8nnered)
   [#6052](https://github.com/realm/SwiftLint/issues/6052)
 
+* Individual `custom_rules` can now be specified in the `only_rule` configuration
+  setting and the `--only-rule` command line option without having to specify
+  `custom_rules` as well. Additionally, violations of custom rules are now reported
+  in a deterministic order, sorted by the rule's identifier.  
+  [Martin Redington](https://github.com/mildm8nnered)
+  [#6029](https://github.com/realm/SwiftLint/issues/6029)
+  [#6058](https://github.com/realm/SwiftLint/issues/6058)
+
 ## 0.59.1: Crisp Spring Clean
 
 ### Breaking

Source/SwiftLintFramework/Configuration/Configuration+Parsing.swift

@@ -87,7 +87,8 @@ extension Configuration {
                 parentConfiguration: parentConfiguration,
                 configurationDictionary: dict,
                 ruleList: ruleList,
-                rulesMode: rulesMode
+                rulesMode: rulesMode,
+                customRuleIdentifiers: Set(allRulesWrapped.customRules?.customRuleIdentifiers ?? [])
             )
         }
 
@@ -167,7 +168,8 @@ extension Configuration {
         parentConfiguration: Configuration?,
         configurationDictionary dict: [String: Any],
         ruleList: RuleList,
-        rulesMode: RulesMode
+        rulesMode: RulesMode,
+        customRuleIdentifiers: Set<String>
     ) {
         for key in dict.keys where !validGlobalKeys.contains(key) {
             guard let identifier = ruleList.identifier(for: key),
@@ -179,7 +181,11 @@ extension Configuration {
             case .allCommandLine, .onlyCommandLine:
                 return
             case .onlyConfiguration(let onlyRules):
-                let issue = validateConfiguredRuleIsEnabled(onlyRules: onlyRules, ruleType: ruleType)
+                let issue = validateConfiguredRuleIsEnabled(
+                    onlyRules: onlyRules,
+                    ruleType: ruleType,
+                    customRuleIdentifiers: customRuleIdentifiers
+                )
                 issue?.print()
             case let .defaultConfiguration(disabled: disabledRules, optIn: optInRules):
                 let issue = validateConfiguredRuleIsEnabled(
@@ -229,9 +235,13 @@ extension Configuration {
 
     static func validateConfiguredRuleIsEnabled(
         onlyRules: Set<String>,
-        ruleType: any Rule.Type
+        ruleType: any Rule.Type,
+        customRuleIdentifiers: Set<String> = []
     ) -> Issue? {
         if onlyRules.isDisjoint(with: ruleType.description.allIdentifiers) {
+            if ruleType is CustomRules.Type, !customRuleIdentifiers.isDisjoint(with: onlyRules) {
+                return nil
+            }
             return Issue.ruleNotPresentInOnlyRules(ruleID: ruleType.identifier)
         }
         return nil

Source/SwiftLintFramework/Configuration/Configuration+RulesMode.swift

@@ -122,7 +122,7 @@ public extension Configuration {
             case let .onlyConfiguration(onlyRules) where onlyRules.contains {
                 $0 == CustomRules.identifier
             }:
-                let customRulesRule = (allRulesWrapped.first { $0.rule is CustomRules })?.rule as? CustomRules
+                let customRulesRule = allRulesWrapped.customRules
                 return .onlyConfiguration(onlyRules.union(Set(customRulesRule?.customRuleIdentifiers ?? [])))
 
             default:

Source/SwiftLintFramework/Configuration/Configuration+RulesWrapper.swift

@@ -11,11 +11,12 @@ internal extension Configuration {
         private let aliasResolver: (String) -> String
 
         private var invalidRuleIdsWarnedAbout: Set<String> = []
+        private var customRulesIdentifiers: Set<String> {
+            Set(allRulesWrapped.customRules?.customRuleIdentifiers ?? [])
+        }
         private var validRuleIdentifiers: Set<String> {
             let regularRuleIdentifiers = allRulesWrapped.map { type(of: $0.rule).identifier }
-            let configurationCustomRulesIdentifiers =
-                (allRulesWrapped.first { $0.rule is CustomRules }?.rule as? CustomRules)?.customRuleIdentifiers ?? []
-            return Set(regularRuleIdentifiers + configurationCustomRulesIdentifiers)
+            return Set(regularRuleIdentifiers + customRulesIdentifiers)
         }
 
         private var cachedResultingRules: [any Rule]?
@@ -45,6 +46,11 @@ internal extension Configuration {
                 resultingRules = allRulesWrapped.filter { tuple in
                     onlyRulesRuleIdentifiers.contains(type(of: tuple.rule).identifier)
                 }.map(\.rule)
+                if !resultingRules.contains(where: { $0 is CustomRules }),
+                   !customRulesIdentifiers.isDisjoint(with: onlyRulesRuleIdentifiers),
+                   let customRules = allRulesWrapped.customRules {
+                    resultingRules.append(customRules)
+                }
 
             case var .defaultConfiguration(disabledRuleIdentifiers, optInRuleIdentifiers):
                 customRulesFilter = { !disabledRuleIdentifiers.contains($0.identifier) }
@@ -200,10 +206,8 @@ internal extension Configuration {
             newAllRulesWrapped: [ConfigurationRuleWrapper], with child: RulesWrapper
         ) -> [ConfigurationRuleWrapper] {
             guard
-                let parentCustomRulesRule = (allRulesWrapped.first { $0.rule is CustomRules })?.rule
-                    as? CustomRules,
-                let childCustomRulesRule = (child.allRulesWrapped.first { $0.rule is CustomRules })?.rule
-                    as? CustomRules
+                let parentCustomRulesRule = allRulesWrapped.customRules,
+                let childCustomRulesRule = child.allRulesWrapped.customRules
             else {
                 // Merging is only needed if both parent & child have a custom rules rule
                 return newAllRulesWrapped
@@ -251,8 +255,7 @@ internal extension Configuration {
                 // Also add identifiers of child custom rules iff the custom_rules rule is enabled
                 // (parent custom rules are already added)
                 if (onlyRules.contains { $0 == CustomRules.identifier }) {
-                    if let childCustomRulesRule = (child.allRulesWrapped.first { $0.rule is CustomRules })?.rule
-                        as? CustomRules {
+                    if let childCustomRulesRule = child.allRulesWrapped.customRules {
                         onlyRules = onlyRules.union(
                             Set(
                                 childCustomRulesRule.customRuleIdentifiers
@@ -310,3 +313,9 @@ internal extension Configuration {
         }
     }
 }
+
+extension [ConfigurationRuleWrapper] {
+    var customRules: CustomRules? {
+        first { $0.rule is CustomRules }?.rule as? CustomRules
+    }
+}

Source/SwiftLintFramework/Rules/CustomRules.swift

@@ -31,6 +31,7 @@ struct CustomRulesConfiguration: RuleConfiguration, CacheDescriptionProvider {
 
             customRuleConfigurations.append(ruleConfiguration)
         }
+        customRuleConfigurations.sort { $0.identifier < $1.identifier }
     }
 }
 

Tests/FrameworkTests/ConfigurationTests.swift

@@ -7,6 +7,7 @@ import XCTest
 
 private let optInRules = RuleRegistry.shared.list.list.filter({ $0.1.init() is any OptInRule }).map(\.0)
 
+// swiftlint:disable:next type_body_length
 final class ConfigurationTests: SwiftLintTestCase {
     // MARK: Setup & Teardown
     private var previousWorkingDir: String! // swiftlint:disable:this implicitly_unwrapped_optional
@@ -142,6 +143,35 @@ final class ConfigurationTests: SwiftLintTestCase {
         )
     }
 
+    func testOnlyRulesWithSpecificCustomRules() throws {
+        // Individual custom rules can be specified on the command line without specifying `custom_rules` as well.
+        let customRuleIdentifier = "my_custom_rule"
+        let customRuleIdentifier2 = "my_custom_rule2"
+        let only = ["custom_rules"]
+        let customRules = [
+            customRuleIdentifier: ["name": "A custom rule", "regex": "this is illegal"],
+            customRuleIdentifier2: ["name": "Another custom rule", "regex": "this is also illegal"],
+        ]
+
+        let config = try Configuration(
+            dict: [
+                "only_rules": only,
+                "custom_rules": customRules,
+            ],
+            onlyRule: [customRuleIdentifier]
+        )
+        guard let resultingCustomRules = config.rules.first(where: { $0 is CustomRules }) as? CustomRules
+        else {
+            XCTFail("Custom rules are expected to be present")
+            return
+        }
+        let enabledCustomRuleIdentifiers =
+            resultingCustomRules.configuration.customRuleConfigurations.map { rule in
+                rule.identifier
+            }
+        XCTAssertEqual(enabledCustomRuleIdentifiers, [customRuleIdentifier])
+    }
+
     func testWarningThreshold_value() throws {
         let config = try Configuration(dict: ["warning_threshold": 5])
         XCTAssertEqual(config.warningThreshold, 5)

Tests/FrameworkTests/CustomRulesTests.swift

@@ -506,6 +506,27 @@ final class CustomRulesTests: SwiftLintTestCase {
         XCTAssertTrue(violations[3].isSuperfluousDisableCommandViolation(for: "rule2"))
     }
 
+    // MARK: - only_rules support
+
+    func testOnlyRulesWithCustomRules() throws {
+        let ruleIdentifierToEnable = "aaa"
+        let violations = try testOnlyRulesWithCustomRules([ruleIdentifierToEnable])
+        XCTAssertEqual(violations.count, 1)
+        XCTAssertEqual(violations[0].ruleIdentifier, ruleIdentifierToEnable)
+    }
+
+    func testOnlyRulesWithIndividualIdentifiers() throws {
+        let customRuleIdentifiers = ["aaa", "bbb"]
+        let violationsWithIndividualRuleIdentifiers = try testOnlyRulesWithCustomRules(customRuleIdentifiers)
+        XCTAssertEqual(violationsWithIndividualRuleIdentifiers.count, 2)
+        XCTAssertEqual(
+            violationsWithIndividualRuleIdentifiers.map { $0.ruleIdentifier },
+            customRuleIdentifiers
+        )
+        let violationsWithCustomRulesIdentifier = try testOnlyRulesWithCustomRules(["custom_rules"])
+        XCTAssertEqual(violationsWithIndividualRuleIdentifiers, violationsWithCustomRulesIdentifier)
+    }
+
     // MARK: - Private
 
     private func getCustomRules(_ extraConfig: [String: Any] = [:]) -> (Configuration, CustomRules) {
@@ -568,6 +589,27 @@ final class CustomRulesTests: SwiftLintTestCase {
         customRules.configuration = customRuleConfiguration
         return customRules
     }
+
+    private func testOnlyRulesWithCustomRules(_ onlyRulesIdentifiers: [String]) throws -> [StyleViolation] {
+        let customRules: [String: Any] = [
+            "aaa": [
+                "regex": "aaa"
+            ],
+            "bbb": [
+                "regex": "bbb"
+            ],
+        ]
+        let example = Example("""
+                              let a = "aaa"
+                              let b = "bbb"
+                              """)
+        let configDict: [String: Any] = [
+            "only_rules": onlyRulesIdentifiers,
+            "custom_rules": customRules,
+        ]
+        let configuration = try SwiftLintFramework.Configuration(dict: configDict)
+        return TestHelpers.violations(example.skipWrappingInCommentTest(), config: configuration)
+    }
 }
 
 private extension StyleViolation {