Add a `summary` table reporter (#4820)

BUILD

@@ -24,6 +24,7 @@ swift_library(
         "@com_github_jpsim_sourcekitten//:SourceKittenFramework",
         "@com_github_apple_swift_syntax//:optlibs",
         "@sourcekitten_com_github_jpsim_yams//:Yams",
+        "@swiftlint_com_github_scottrhoyt_swifty_text_table//:SwiftyTextTable",	
     ] + select({
         "@platforms//os:linux": ["@com_github_krzyzanowskim_cryptoswift//:CryptoSwift"],
         "//conditions:default": [],

CHANGELOG.md

@@ -111,6 +111,10 @@
   [Martin Redington](https://github.com/mildm8nnered)
   [#4248](https://github.com/realm/SwiftLint/issues/4248)
 
+* Adds a new `summary` reporter, that displays the number of violations
+  of each rule in a text table.  
+  [Martin Redington](https://github.com/mildm8nnered)
+
 #### Bug Fixes
 
 * Report violations in all `<scope>_length` rules when the error threshold is

Package.swift

@@ -61,7 +61,7 @@ let package = Package(
         ),
         .target(
             name: "SwiftLintFramework",
-            dependencies: frameworkDependencies
+            dependencies: frameworkDependencies + ["SwiftyTextTable"]
         ),
         .target(
             name: "SwiftLintTestHelpers",

Source/SwiftLintFramework/Protocols/Reporter.swift

@@ -49,6 +49,8 @@ public func reporterFrom(identifier: String) -> Reporter.Type { // swiftlint:dis
         return CodeClimateReporter.self
     case RelativePathReporter.identifier:
         return RelativePathReporter.self
+    case SummaryReporter.identifier:
+        return SummaryReporter.self
     default:
         queuedFatalError("no reporter with identifier '\(identifier)' available.")
     }

Source/SwiftLintFramework/Reporters/SummaryReporter.swift

@@ -0,0 +1,128 @@
+import Foundation
+import SwiftyTextTable
+
+/// Reports a summary table of all violations
+public struct SummaryReporter: Reporter {
+    // MARK: - Reporter Conformance
+
+    public static let identifier = "summary"
+    public static let isRealtime = false
+
+    public var description: String {
+        return "Reports a summary table of all violations."
+    }
+
+    public static func generateReport(_ violations: [StyleViolation]) -> String {
+        TextTable(violations: violations).renderWithExtraSeparator()
+    }
+}
+
+// MARK: - SwiftyTextTable
+
+private extension TextTable {
+    // swiftlint:disable:next function_body_length
+    init(violations: [StyleViolation]) {
+        let numberOfWarningsHeader = "warnings"
+        let numberOfErrorsHeader = "errors"
+        let numberOfViolationsHeader = "total violations"
+        let numberOfFilesHeader = "number of files"
+        let columns = [
+            TextTableColumn(header: "rule identifier"),
+            TextTableColumn(header: "opt-in"),
+            TextTableColumn(header: "correctable"),
+            TextTableColumn(header: "custom"),
+            TextTableColumn(header: numberOfWarningsHeader),
+            TextTableColumn(header: numberOfErrorsHeader),
+            TextTableColumn(header: numberOfViolationsHeader),
+            TextTableColumn(header: numberOfFilesHeader)
+        ]
+        self.init(columns: columns)
+
+        let ruleIdentifiersToViolationsMap = violations.group { $0.ruleIdentifier }
+        let sortedRuleIdentifiers = ruleIdentifiersToViolationsMap.keys.sorted {
+            let count1 = ruleIdentifiersToViolationsMap[$0]?.count ?? 0
+            let count2 = ruleIdentifiersToViolationsMap[$1]?.count ?? 0
+            if count1 > count2 {
+                return true
+            } else if count1 == count2 {
+                return $0 < $1
+            }
+            return false
+        }
+
+        var totalNumberOfWarnings = 0
+        var totalNumberOfErrors = 0
+
+        for ruleIdentifier in sortedRuleIdentifiers {
+            guard let ruleIdentifier = ruleIdentifiersToViolationsMap[ruleIdentifier]?.first?.ruleIdentifier else {
+                continue
+            }
+
+            let rule = primaryRuleList.list[ruleIdentifier]
+            let violations = ruleIdentifiersToViolationsMap[ruleIdentifier]
+            let numberOfWarnings = violations?.filter { $0.severity == .warning }.count ?? 0
+            let numberOfErrors = violations?.filter { $0.severity == .error }.count ?? 0
+            let numberOfViolations = numberOfWarnings + numberOfErrors
+            totalNumberOfWarnings += numberOfWarnings
+            totalNumberOfErrors += numberOfErrors
+            let ruleViolations = ruleIdentifiersToViolationsMap[ruleIdentifier] ?? []
+            let numberOfFiles = Set(ruleViolations.map { $0.location.file }).count
+
+            addRow(values: [
+                ruleIdentifier,
+                rule is OptInRule ? "yes" : "no",
+                rule is CorrectableRule ? "yes" : "no",
+                rule == nil ? "yes" : "no",
+                numberOfWarnings.formattedString.leftPadded(forHeader: numberOfWarningsHeader),
+                numberOfErrors.formattedString.leftPadded(forHeader: numberOfErrorsHeader),
+                numberOfViolations.formattedString.leftPadded(forHeader: numberOfViolationsHeader),
+                numberOfFiles.formattedString.leftPadded(forHeader: numberOfFilesHeader)
+            ])
+        }
+
+        let totalNumberOfViolations = totalNumberOfWarnings + totalNumberOfErrors
+        let totalNumberOfFiles = Set(violations.map { $0.location.file }).count
+        addRow(values: [
+            "Total",
+            "",
+            "",
+            "",
+            totalNumberOfWarnings.formattedString.leftPadded(forHeader: numberOfWarningsHeader),
+            totalNumberOfErrors.formattedString.leftPadded(forHeader: numberOfErrorsHeader),
+            totalNumberOfViolations.formattedString.leftPadded(forHeader: numberOfViolationsHeader),
+            totalNumberOfFiles.formattedString.leftPadded(forHeader: numberOfFilesHeader)
+        ])
+    }
+
+    func renderWithExtraSeparator() -> String {
+        var output = render()
+        var lines = output.components(separatedBy: "\n")
+        if lines.count > 5, let lastLine = lines.last {
+            lines.insert(lastLine, at: lines.count - 2)
+            output = lines.joined(separator: "\n")
+        }
+        return output
+    }
+}
+
+private extension String {
+    func leftPadded(forHeader header: String) -> String {
+        let headerCount = header.count - self.count
+        if headerCount > 0 {
+            return String(repeating: " ", count: headerCount) + self
+        }
+        return self
+    }
+}
+
+private extension Int {
+    private static var numberFormatter: NumberFormatter = {
+        let numberFormatter = NumberFormatter()
+        numberFormatter.numberStyle = .decimal
+        return numberFormatter
+    }()
+    var formattedString: String {
+        // swiftlint:disable:next legacy_objc_type
+        Int.numberFormatter.string(from: NSNumber(value: self)) ?? ""
+    }
+}

Tests/SwiftLintFrameworkTests/ReporterTests.swift

@@ -6,19 +6,20 @@ import XCTest
 class ReporterTests: XCTestCase {
     func testReporterFromString() {
         let reporters: [Reporter.Type] = [
-            XcodeReporter.self,
-            JSONReporter.self,
-            CSVReporter.self,
             CheckstyleReporter.self,
             CodeClimateReporter.self,
-            JUnitReporter.self,
-            HTMLReporter.self,
+            CSVReporter.self,
             EmojiReporter.self,
-            SonarQubeReporter.self,
-            MarkdownReporter.self,
             GitHubActionsLoggingReporter.self,
             GitLabJUnitReporter.self,
-            RelativePathReporter.self
+            HTMLReporter.self,
+            JSONReporter.self,
+            JUnitReporter.self,
+            MarkdownReporter.self,
+            RelativePathReporter.self,
+            SonarQubeReporter.self,
+            SummaryReporter.self,
+            XcodeReporter.self
         ]
         for reporter in reporters {
             XCTAssertEqual(reporter.identifier, reporterFrom(identifier: reporter.identifier).identifier)
@@ -43,7 +44,7 @@ class ReporterTests: XCTestCase {
                            severity: .error,
                            location: location,
                            reason: "Shorthand syntactic sugar should be used" +
-                                   ", i.e. [Int] instead of Array<Int>"),
+                           ", i.e. [Int] instead of Array<Int>"),
             StyleViolation(ruleDescription: ColonRule.description,
                            severity: .error,
                            location: Location(file: nil),
@@ -155,4 +156,18 @@ class ReporterTests: XCTestCase {
         XCTAssertFalse(result.contains(absolutePath))
         XCTAssertTrue(result.contains(relativePath))
     }
+
+    func testSummaryReporter() {
+        let expectedOutput = stringFromFile("CannedSummaryReporterOutput.txt")
+            .trimmingTrailingCharacters(in: .whitespacesAndNewlines)
+        let result = SummaryReporter.generateReport(generateViolations())
+        XCTAssertEqual(result, expectedOutput)
+    }
+
+    func testSummaryReporterWithNoViolations() {
+        let expectedOutput = stringFromFile("CannedSummaryReporterNoViolationsOutput.txt")
+            .trimmingTrailingCharacters(in: .whitespacesAndNewlines)
+        let result = SummaryReporter.generateReport([])
+        XCTAssertEqual(result, expectedOutput)
+    }
 }

Tests/SwiftLintFrameworkTests/Resources/CannedSummaryReporterNoViolationsOutput.txt

@@ -0,0 +1,5 @@
++-----------------+--------+-------------+--------+----------+--------+------------------+-----------------+
+| rule identifier | opt-in | correctable | custom | warnings | errors | total violations | number of files |
++-----------------+--------+-------------+--------+----------+--------+------------------+-----------------+
+| Total           |        |             |        |        0 |      0 |                0 |               0 |
++-----------------+--------+-------------+--------+----------+--------+------------------+-----------------+

Tests/SwiftLintFrameworkTests/Resources/CannedSummaryReporterOutput.txt

@@ -0,0 +1,9 @@
++-----------------+--------+-------------+--------+----------+--------+------------------+-----------------+
+| rule identifier | opt-in | correctable | custom | warnings | errors | total violations | number of files |
++-----------------+--------+-------------+--------+----------+--------+------------------+-----------------+
+| line_length     | no     | no          | no     |        1 |      1 |                2 |               1 |
+| colon           | no     | no          | no     |        0 |      1 |                1 |               1 |
+| syntactic_sugar | no     | no          | no     |        0 |      1 |                1 |               1 |
++-----------------+--------+-------------+--------+----------+--------+------------------+-----------------+
+| Total           |        |             |        |        1 |      3 |                4 |               2 |
++-----------------+--------+-------------+--------+----------+--------+------------------+-----------------+