Improve file_length warnings when excluding comments (realm#3654)

* Improve `file_length` warnings when excluding comments

* Update changelog

* Update Source/SwiftLintFramework/Rules/Metrics/FileLengthRule.swift

Co-authored-by: Yegor Chsherbatykh <[email protected]>

Co-authored-by: Steven Grosmark <[email protected]>
Co-authored-by: Yegor Chsherbatykh <[email protected]>

Author: 3 people

CHANGELOG.md

@@ -30,6 +30,11 @@
   [Kane Cheshire](https://github.com/kanecheshire)
   [#3624](https://github.com/realm/SwiftLint/issues/3624)
 
+* Improve language and positioning of `file_length` warnings when
+  `ignore_comment_only_lines: true`.  
+  [Steven Grosmark](https://github.com/g-mark)
+  [#3654](https://github.com/realm/SwiftLint/pull/3654)
+
 #### Bug Fixes
 
 * Fix false positives in `empty_enum_arguments` rule when comparing values

Source/SwiftLintFramework/Rules/Metrics/FileLengthRule.swift

@@ -15,7 +15,8 @@ public struct FileLengthRule: ConfigurationProviderRule {
         ],
         triggeringExamples: [
             Example(repeatElement("print(\"swiftlint\")\n", count: 401).joined()),
-            Example((repeatElement("print(\"swiftlint\")\n", count: 400) + ["//\n"]).joined())
+            Example((repeatElement("print(\"swiftlint\")\n", count: 400) + ["//\n"]).joined()),
+            Example(repeatElement("print(\"swiftlint\")\n\n", count: 201).joined())
         ]
     )
 
@@ -38,11 +39,12 @@ public struct FileLengthRule: ConfigurationProviderRule {
         }
 
         for parameter in configuration.severityConfiguration.params where lineCount > parameter.value {
-            let reason = "File should contain \(configuration.severityConfiguration.warning) lines or less: " +
-                         "currently contains \(lineCount)"
+            let reason = "File should contain \(configuration.severityConfiguration.warning) lines or less" +
+                         (configuration.ignoreCommentOnlyLines ? " excluding comments and whitespaces" : "") +
+                         ": currently contains \(lineCount)"
             return [StyleViolation(ruleDescription: Self.description,
                                    severity: parameter.severity,
-                                   location: Location(file: file.path, line: lineCount),
+                                   location: Location(file: file.path, line: file.lines.count),
                                    reason: reason)]
         }
 

Tests/SwiftLintFrameworkTests/FileLengthRuleTests.swift

@@ -13,7 +13,8 @@ class FileLengthRuleTests: XCTestCase {
         ]
         let nonTriggeringExamples = [
             Example((repeatElement("print(\"swiftlint\")\n", count: 400) + ["//\n"]).joined()),
-            Example(repeatElement("print(\"swiftlint\")\n", count: 400).joined())
+            Example(repeatElement("print(\"swiftlint\")\n", count: 400).joined()),
+            Example(repeatElement("print(\"swiftlint\")\n\n", count: 201).joined())
         ]
 
         let description = FileLengthRule.description