Add coverage statistics

CHANGELOG.md

@@ -22,7 +22,12 @@
 
 #### Experimental
 
-* None.
+* Adds a new `--report-coverage` command line option for the `lint` and `analyze` subcommands, and an
+  equivalent `report_coverage` configuration file setting. Coverage is measured against enabled
+  rules (reflecting disablement of enabled rules via `swiftlint:disable`), and also against all linter
+  or analyzer rules (reflecting the actual usage of Swiftlint versus its potential).  
+  [Martin Redington](https://github.com/mildm8nnered)
+  [#5907](https://github.com/realm/SwiftLint/issues/5907)
 
 #### Enhancements
 

README.md

@@ -735,6 +735,9 @@ write_baseline: Baseline.json
 # If true, SwiftLint will check for updates after linting or analyzing.
 check_for_updates: true
 
+# If true, SwiftLint will report coverage statistics after linting or analyzing.
+report_coverage: true
+
 # configurable rules can be customized from this configuration file
 # binary rules can set their severity level
 force_cast: warning # implicitly

Source/SwiftLintCore/Extensions/SwiftLintFile+Cache.swift

@@ -42,6 +42,9 @@ private let commandsCache = Cache { file -> [Command] in
     return CommandVisitor(locationConverter: file.locationConverter)
         .walk(file: file, handler: \.commands)
 }
+private let regionsCache = Cache { file -> [Region] in
+    file.regions()
+}
 private let syntaxMapCache = Cache { file in
     responseCache.get(file).map { SwiftLintSyntaxMap(value: SyntaxMap(sourceKitResponse: $0)) }
 }
@@ -168,6 +171,8 @@ extension SwiftLintFile {
 
     public var invalidCommands: [Command] { commandsCache.get(self).filter { !$0.isValid } }
 
+    public var regions: [Region] { regionsCache.get(self) }
+
     public var syntaxTokensByLines: [[SwiftLintSyntaxToken]] {
         guard let syntaxTokensByLines = syntaxTokensByLinesCache.get(self) else {
             if let handler = assertHandler {
@@ -204,6 +209,7 @@ extension SwiftLintFile {
         foldedSyntaxTreeCache.invalidate(self)
         locationConverterCache.invalidate(self)
         commandsCache.invalidate(self)
+        regionsCache.invalidate(self)
         linesWithTokensCache.invalidate(self)
     }
 
@@ -219,6 +225,7 @@ extension SwiftLintFile {
         foldedSyntaxTreeCache.clear()
         locationConverterCache.clear()
         commandsCache.clear()
+        regionsCache.clear()
         linesWithTokensCache.clear()
     }
 }

Source/SwiftLintCore/Extensions/SwiftLintFile+Regex.swift

@@ -268,7 +268,7 @@ extension SwiftLintFile {
     }
 
     public func ruleEnabled(violatingRanges: [NSRange], for rule: some Rule) -> [NSRange] {
-        let fileRegions = regions()
+        let fileRegions = regions
         if fileRegions.isEmpty { return violatingRanges }
         return violatingRanges.filter { range in
             let region = fileRegions.first {

Source/SwiftLintCore/Protocols/SwiftSyntaxCorrectableRule.swift

@@ -47,7 +47,7 @@ public extension SwiftSyntaxCorrectableRule {
         }
 
         let locationConverter = file.locationConverter
-        let disabledRegions = file.regions()
+        let disabledRegions = file.regions
             .filter { $0.areRulesDisabled(ruleIDs: Self.description.allIdentifiers) }
             .compactMap { $0.toSourceRange(locationConverter: locationConverter) }
 
@@ -91,7 +91,7 @@ open class ViolationsSyntaxRewriter<Configuration: RuleConfiguration>: SyntaxRew
     public lazy var locationConverter = file.locationConverter
     /// The regions in the traversed file that are disabled by a command.
     public lazy var disabledRegions = {
-        file.regions()
+        file.regions
             .filter { $0.areRulesDisabled(ruleIDs: Configuration.Parent.description.allIdentifiers) }
             .compactMap { $0.toSourceRange(locationConverter: locationConverter) }
     }()

Source/SwiftLintFramework/Configuration/Configuration+Merging.swift

@@ -22,6 +22,7 @@ extension Configuration {
             excludedPaths: mergedIncludedAndExcluded.excludedPaths,
             indentation: childConfiguration.indentation,
             warningThreshold: mergedWarningTreshold(with: childConfiguration),
+            reportCoverage: childConfiguration.reportCoverage,
             reporter: reporter,
             cachePath: cachePath,
             allowZeroLintableFiles: childConfiguration.allowZeroLintableFiles,

Source/SwiftLintFramework/Configuration/Configuration+Parsing.swift

@@ -7,6 +7,7 @@ extension Configuration {
         case excluded = "excluded"
         case included = "included"
         case optInRules = "opt_in_rules"
+        case reportCoverage = "report_coverage"
         case reporter = "reporter"
         case swiftlintVersion = "swiftlint_version"
         case warningThreshold = "warning_threshold"
@@ -99,6 +100,7 @@ extension Configuration {
             excludedPaths: defaultStringArray(dict[Key.excluded.rawValue]),
             indentation: Self.getIndentationLogIfInvalid(from: dict),
             warningThreshold: dict[Key.warningThreshold.rawValue] as? Int,
+            reportCoverage: dict[Key.reportCoverage.rawValue] as? Bool ?? false,
             reporter: dict[Key.reporter.rawValue] as? String ?? XcodeReporter.identifier,
             cachePath: cachePath ?? dict[Key.cachePath.rawValue] as? String,
             pinnedVersion: dict[Key.swiftlintVersion.rawValue].map { ($0 as? String) ?? String(describing: $0) },

Source/SwiftLintFramework/Configuration/Configuration.swift

@@ -26,6 +26,9 @@ public struct Configuration {
     /// The threshold for the number of warnings to tolerate before treating the lint as having failed.
     public let warningThreshold: Int?
 
+    /// Report coverage statistics when linting or analyzing.
+    public let reportCoverage: Bool
+
     /// The identifier for the `Reporter` to use to report style violations.
     public let reporter: String?
 
@@ -47,7 +50,7 @@ public struct Configuration {
     /// The path to write a baseline to.
     public let writeBaseline: String?
 
-    /// Check for updates.
+    /// Check for updates after linting or analyzing.`
     public let checkForUpdates: Bool
 
     /// This value is `true` iff the `--config` parameter was used to specify (a) configuration file(s)
@@ -82,6 +85,7 @@ public struct Configuration {
         excludedPaths: [String],
         indentation: IndentationStyle,
         warningThreshold: Int?,
+        reportCoverage: Bool,
         reporter: String?,
         cachePath: String?,
         allowZeroLintableFiles: Bool,
@@ -97,6 +101,7 @@ public struct Configuration {
         self.excludedPaths = excludedPaths
         self.indentation = indentation
         self.warningThreshold = warningThreshold
+        self.reportCoverage = reportCoverage
         self.reporter = reporter
         self.cachePath = cachePath
         self.allowZeroLintableFiles = allowZeroLintableFiles
@@ -117,6 +122,7 @@ public struct Configuration {
         excludedPaths = configuration.excludedPaths
         indentation = configuration.indentation
         warningThreshold = configuration.warningThreshold
+        reportCoverage = configuration.reportCoverage
         reporter = configuration.reporter
         basedOnCustomConfigurationFiles = configuration.basedOnCustomConfigurationFiles
         cachePath = configuration.cachePath
@@ -143,6 +149,7 @@ public struct Configuration {
     /// - parameter indentation:            The style to use when indenting Swift source code.
     /// - parameter warningThreshold:       The threshold for the number of warnings to tolerate before treating the
     ///                                     lint as having failed.
+    /// - parameter reportCoverage:         Report coverage data after linting or analyzing.
     /// - parameter reporter:               The identifier for the `Reporter` to use to report style violations.
     /// - parameter cachePath:              The location of the persisted cache to use with this configuration.
     /// - parameter pinnedVersion:          The SwiftLint version defined in this configuration.
@@ -152,7 +159,7 @@ public struct Configuration {
     /// - parameter lenient:                Treat errors as warnings.
     /// - parameter baseline:               The path to read a baseline from.
     /// - parameter writeBaseline:          The path to write a baseline to.
-    /// - parameter checkForUpdates:        Check for updates to SwiftLint.
+    /// - parameter checkForUpdates:        Check for updates to SwiftLint after linting or analyzing.
     package init(
         rulesMode: RulesMode = .defaultConfiguration(disabled: [], optIn: []),
         allRulesWrapped: [ConfigurationRuleWrapper]? = nil,
@@ -162,6 +169,7 @@ public struct Configuration {
         excludedPaths: [String] = [],
         indentation: IndentationStyle = .default,
         warningThreshold: Int? = nil,
+        reportCoverage: Bool = false,
         reporter: String? = nil,
         cachePath: String? = nil,
         pinnedVersion: String? = nil,
@@ -193,6 +201,7 @@ public struct Configuration {
             excludedPaths: excludedPaths,
             indentation: indentation,
             warningThreshold: warningThreshold,
+            reportCoverage: reportCoverage,
             reporter: reporter,
             cachePath: cachePath,
             allowZeroLintableFiles: allowZeroLintableFiles,
@@ -310,6 +319,7 @@ extension Configuration: Hashable {
         hasher.combine(excludedPaths)
         hasher.combine(indentation)
         hasher.combine(warningThreshold)
+        hasher.combine(reportCoverage)
         hasher.combine(reporter)
         hasher.combine(allowZeroLintableFiles)
         hasher.combine(strict)
@@ -328,6 +338,7 @@ extension Configuration: Hashable {
             lhs.excludedPaths == rhs.excludedPaths &&
             lhs.indentation == rhs.indentation &&
             lhs.warningThreshold == rhs.warningThreshold &&
+            lhs.reportCoverage == rhs.reportCoverage &&
             lhs.reporter == rhs.reporter &&
             lhs.basedOnCustomConfigurationFiles == rhs.basedOnCustomConfigurationFiles &&
             lhs.cachePath == rhs.cachePath &&