Add prefer_scaled_to_fit opt-in rule

CHANGELOG.md

@@ -71,6 +71,12 @@
   The modern replacement is safer, cleaner, Retina-aware and more performant.  
   [Dimitri Dupuis-Latour](https://github.com/DimDL)
   [#6268](https://github.com/realm/SwiftLint/issues/6268)
+
+* Add `prefer_scaled_to_fit` opt-in rule to prefer `scaledToFit()` and
+  `scaledToFill()` over `aspectRatio(contentMode:)` with a constant
+  content mode.  
+  [DemiDevv](https://github.com/DemiDevv)
+  [#5713](https://github.com/realm/SwiftLint/issues/5713)
 
 * Support access level modifiers on imports in `unused_imports` rule.  
   [SimplyDanny](https://github.com/SimplyDanny)

Source/SwiftLintBuiltInRules/Models/BuiltInRules.swift

@@ -158,6 +158,7 @@ public let builtInRules: [any Rule.Type] = [
     PreferConditionListRule.self,
     PreferKeyPathRule.self,
     PreferNimbleRule.self,
+    PreferScaledToFitRule.self,
     PreferSelfInStaticReferencesRule.self,
     PreferSelfTypeOverTypeOfSelfRule.self,
     PreferTypeCheckingRule.self,

Source/SwiftLintBuiltInRules/Rules/Idiomatic/PreferScaledToFitRule.swift

@@ -0,0 +1,70 @@
+import SwiftLintCore
+import SwiftSyntax
+
+@SwiftSyntaxRule(optIn: true)
+struct PreferScaledToFitRule: Rule {
+    var configuration = SeverityConfiguration<Self>(.warning)
+
+    static let description = RuleDescription(
+        identifier: "prefer_scaled_to_fit",
+        name: "Prefer Scaled To Fit",
+        description: "Prefer `scaledToFit()` or `scaledToFill()` over " +
+        "`aspectRatio(contentMode:)` with a constant content mode",
+        kind: .idiomatic,
+        nonTriggeringExamples: [
+            Example("view.aspectRatio(ratio, contentMode: .fit)"),
+            Example("view.aspectRatio(ratio, contentMode: .fill)"),
+            Example("view.aspectRatio(contentMode: contentMode)"),
+            Example("view.aspectRatio(contentMode: shouldFit ? .fit : .fill)"),
+            Example("view.scaledToFit()"),
+            Example("view.scaledToFill()"),
+        ],
+        triggeringExamples: [
+            Example("view.↓aspectRatio(contentMode: .fit)"),
+            Example("view.↓aspectRatio(contentMode: .fill)"),
+            Example("↓aspectRatio(contentMode: .fit)"),
+            Example("↓aspectRatio(contentMode: .fill)"),
+        ]
+    )
+}
+
+private extension PreferScaledToFitRule {
+    final class Visitor: ViolationsSyntaxVisitor<ConfigurationType> {
+        override func visitPost(_ node: FunctionCallExprSyntax) {
+            let functionName: String
+            let violationPosition: AbsolutePosition
+
+            if let memberAccess = node.calledExpression.as(MemberAccessExprSyntax.self) {
+                functionName = memberAccess.declName.baseName.text
+                violationPosition = memberAccess.declName.baseName.positionAfterSkippingLeadingTrivia
+            } else if let declRef = node.calledExpression.as(DeclReferenceExprSyntax.self) {
+                functionName = declRef.baseName.text
+                violationPosition = declRef.baseName.positionAfterSkippingLeadingTrivia
+            } else {
+                return
+            }
+
+            guard functionName == "aspectRatio" else {
+                return
+            }
+
+            guard
+                node.arguments.count == 1,
+                let argument = node.arguments.first,
+                argument.label?.text == "contentMode"
+            else {
+                return
+            }
+
+            guard
+                let memberValue = argument.expression.as(MemberAccessExprSyntax.self),
+                let valueName = memberValue.declName.baseName.text as String?,
+                valueName == "fit" || valueName == "fill"
+            else {
+                return
+            }
+
+            violations.append(violationPosition)
+        }
+    }
+}

Tests/GeneratedTests/GeneratedTests_07.swift

@@ -43,6 +43,12 @@ final class PreferNimbleRuleGeneratedTests: SwiftLintTestCase {
     }
 }
 
+final class PreferScaledToFitRuleGeneratedTests: SwiftLintTestCase {
+    func testWithDefaultConfiguration() {
+        verifyRule(PreferScaledToFitRule.description)
+    }
+}
+
 final class PreferSelfInStaticReferencesRuleGeneratedTests: SwiftLintTestCase {
     func testWithDefaultConfiguration() {
         verifyRule(PreferSelfInStaticReferencesRule.description)
@@ -150,9 +156,3 @@ final class RawValueForCamelCasedCodableEnumRuleGeneratedTests: SwiftLintTestCas
         verifyRule(RawValueForCamelCasedCodableEnumRule.description)
     }
 }
-
-final class ReduceBooleanRuleGeneratedTests: SwiftLintTestCase {
-    func testWithDefaultConfiguration() {
-        verifyRule(ReduceBooleanRule.description)
-    }
-}

Tests/GeneratedTests/GeneratedTests_08.swift

@@ -7,6 +7,12 @@
 @testable import SwiftLintCore
 import TestHelpers
 
+final class ReduceBooleanRuleGeneratedTests: SwiftLintTestCase {
+    func testWithDefaultConfiguration() {
+        verifyRule(ReduceBooleanRule.description)
+    }
+}
+
 final class ReduceIntoRuleGeneratedTests: SwiftLintTestCase {
     func testWithDefaultConfiguration() {
         verifyRule(ReduceIntoRule.description)
@@ -150,9 +156,3 @@ final class SortedImportsRuleGeneratedTests: SwiftLintTestCase {
         verifyRule(SortedImportsRule.description)
     }
 }
-
-final class StatementPositionRuleGeneratedTests: SwiftLintTestCase {
-    func testWithDefaultConfiguration() {
-        verifyRule(StatementPositionRule.description)
-    }
-}

Tests/GeneratedTests/GeneratedTests_09.swift

@@ -7,6 +7,12 @@
 @testable import SwiftLintCore
 import TestHelpers
 
+final class StatementPositionRuleGeneratedTests: SwiftLintTestCase {
+    func testWithDefaultConfiguration() {
+        verifyRule(StatementPositionRule.description)
+    }
+}
+
 final class StaticOperatorRuleGeneratedTests: SwiftLintTestCase {
     func testWithDefaultConfiguration() {
         verifyRule(StaticOperatorRule.description)
@@ -150,9 +156,3 @@ final class UnneededBreakInSwitchRuleGeneratedTests: SwiftLintTestCase {
         verifyRule(UnneededBreakInSwitchRule.description)
     }
 }
-
-final class UnneededEscapingRuleGeneratedTests: SwiftLintTestCase {
-    func testWithDefaultConfiguration() {
-        verifyRule(UnneededEscapingRule.description)
-    }
-}

Tests/GeneratedTests/GeneratedTests_10.swift

@@ -7,6 +7,12 @@
 @testable import SwiftLintCore
 import TestHelpers
 
+final class UnneededEscapingRuleGeneratedTests: SwiftLintTestCase {
+    func testWithDefaultConfiguration() {
+        verifyRule(UnneededEscapingRule.description)
+    }
+}
+
 final class UnneededOverrideRuleGeneratedTests: SwiftLintTestCase {
     func testWithDefaultConfiguration() {
         verifyRule(UnneededOverrideRule.description)
@@ -150,9 +156,3 @@ final class VoidReturnRuleGeneratedTests: SwiftLintTestCase {
         verifyRule(VoidReturnRule.description)
     }
 }
-
-final class WeakDelegateRuleGeneratedTests: SwiftLintTestCase {
-    func testWithDefaultConfiguration() {
-        verifyRule(WeakDelegateRule.description)
-    }
-}

Tests/GeneratedTests/GeneratedTests_11.swift

@@ -7,6 +7,12 @@
 @testable import SwiftLintCore
 import TestHelpers
 
+final class WeakDelegateRuleGeneratedTests: SwiftLintTestCase {
+    func testWithDefaultConfiguration() {
+        verifyRule(WeakDelegateRule.description)
+    }
+}
+
 final class XCTFailMessageRuleGeneratedTests: SwiftLintTestCase {
     func testWithDefaultConfiguration() {
         verifyRule(XCTFailMessageRule.description)

Tests/IntegrationTests/Resources/default_rule_configurations.yml

@@ -914,6 +914,11 @@ prefer_nimble:
   meta:
     opt-in: true
     correctable: false
+prefer_scaled_to_fit:
+  severity: warning
+  meta:
+    opt-in: true
+    correctable: false
 prefer_self_in_static_references:
   severity: warning
   meta: