Allow user to customize additional variable names to be replaced by self with the strongifiedSelf rule

Rules.md

@@ -1300,7 +1300,11 @@ As per Apple's recommendation
 
 ## strongifiedSelf
 
-Remove backticks around `self` in Optional unwrap expressions.
+Standardize to use self when strongifying self. Remove backticks around `self`.
+
+Option | Description
+--- | ---
+`--strongselfids` | Comma-delimited list of ids that should be replaced with self
 
 <details>
 <summary>Examples</summary>

Sources/Options.swift

@@ -263,6 +263,7 @@ public struct FormatOptions: CustomStringConvertible {
     public var tabWidth: Int
     public var maxWidth: Int
     public var noSpaceOperators: [String]
+    public var strongSelfIds: [String]
 
     // Deprecated
     public var indentComments: Bool
@@ -314,6 +315,7 @@ public struct FormatOptions: CustomStringConvertible {
                 tabWidth: Int = 0,
                 maxWidth: Int = 0,
                 noSpaceOperators: [String] = [],
+                strongSelfIds: [String] = [],
                 // Doesn't really belong here, but hard to put elsewhere
                 fragment: Bool = false,
                 ignoreConflictMarkers: Bool = false,
@@ -357,6 +359,7 @@ public struct FormatOptions: CustomStringConvertible {
         self.tabWidth = tabWidth
         self.maxWidth = maxWidth
         self.noSpaceOperators = noSpaceOperators
+        self.strongSelfIds = strongSelfIds
         // Doesn't really belong here, but hard to put elsewhere
         self.fragment = fragment
         self.ignoreConflictMarkers = ignoreConflictMarkers

Sources/OptionsDescriptor.swift

@@ -252,6 +252,7 @@ extension FormatOptions.Descriptor {
         tabWidth,
         maxWidth,
         noSpaceOperators,
+        strongSelfIds,
 
         // Deprecated
         indentComments,
@@ -577,6 +578,13 @@ extension FormatOptions.Descriptor {
             }
         }
     )
+    static let strongSelfIds = FormatOptions.Descriptor(
+        argumentName: "strongselfids",
+        propertyName: "strongSelfIds",
+        displayName: "Strongified Self Identifiers",
+        help: "Comma-delimited list of ids that should be replaced with self",
+        keyPath: \FormatOptions.strongSelfIds
+    )
 
     // MARK: - Internal
 

Sources/Rules.swift

@@ -3758,20 +3758,24 @@ public struct _FormatRules {
         }
     }
 
-    /// Removed backticks from `self` when strongifying
+    /// Standardize to use self when strongifying self
     public let strongifiedSelf = FormatRule(
-        help: "Remove backticks around `self` in Optional unwrap expressions."
+        help: "Standardize to use self when strongifying self. Remove backticks around `self`.",
+        options: ["strongselfids"]
     ) { formatter in
         guard formatter.options.swiftVersion >= "4.2" else {
             return
         }
-        formatter.forEach(.identifier("`self`")) { i, _ in
-            guard let equalIndex = formatter.index(of: .nonSpaceOrCommentOrLinebreak, after: i, if: {
-                $0 == .operator("=", .infix)
-            }), formatter.next(.nonSpaceOrCommentOrLinebreak, after: equalIndex) == .identifier("self") else {
-                return
+        let strongSelfIds = formatter.options.strongSelfIds + ["`self`"]
+        strongSelfIds.forEach { idName in
+            formatter.forEach(.identifier(idName)) { i, _ in
+                guard let equalIndex = formatter.index(of: .nonSpaceOrCommentOrLinebreak, after: i, if: {
+                    $0 == .operator("=", .infix)
+                }), formatter.next(.nonSpaceOrCommentOrLinebreak, after: equalIndex) == .identifier("self") else {
+                    return
+                }
+                formatter.replaceToken(at: i, with: .identifier("self"))
             }
-            formatter.replaceToken(at: i, with: .identifier("self"))
         }
     }
 

Tests/ArgumentsTests.swift

@@ -200,7 +200,7 @@ class ArgumentsTests: XCTestCase {
     }
 
     func testCommandLineArgumentsAreCorrect() {
-        let output = ["allman": "false", "wraparguments": "preserve", "stripunusedargs": "always", "self": "remove", "header": "ignore", "importgrouping": "alphabetized", "fractiongrouping": "disabled", "binarygrouping": "4,8", "octalgrouping": "4,8", "indentcase": "false", "trimwhitespace": "always", "decimalgrouping": "3,6", "exponentgrouping": "disabled", "patternlet": "hoist", "commas": "always", "wrapcollections": "preserve", "semicolons": "inline", "indent": "4", "exponentcase": "lowercase", "operatorfunc": "spaced", "symlinks": "ignore", "elseposition": "same-line", "empty": "void", "hexliteralcase": "uppercase", "linebreaks": "lf", "hexgrouping": "4,8", "ifdef": "indent", "closingparen": "balanced", "selfrequired": "", "trailingclosures": "", "xcodeindentation": "disabled", "fragment": "false", "conflictmarkers": "reject", "tabwidth": "unspecified", "maxwidth": "none", "nospaceoperators": ""]
+        let output = ["allman": "false", "wraparguments": "preserve", "stripunusedargs": "always", "self": "remove", "header": "ignore", "importgrouping": "alphabetized", "fractiongrouping": "disabled", "binarygrouping": "4,8", "octalgrouping": "4,8", "indentcase": "false", "trimwhitespace": "always", "decimalgrouping": "3,6", "exponentgrouping": "disabled", "patternlet": "hoist", "commas": "always", "wrapcollections": "preserve", "semicolons": "inline", "indent": "4", "exponentcase": "lowercase", "operatorfunc": "spaced", "symlinks": "ignore", "elseposition": "same-line", "empty": "void", "hexliteralcase": "uppercase", "linebreaks": "lf", "hexgrouping": "4,8", "ifdef": "indent", "closingparen": "balanced", "selfrequired": "", "trailingclosures": "", "xcodeindentation": "disabled", "fragment": "false", "conflictmarkers": "reject", "tabwidth": "unspecified", "maxwidth": "none", "nospaceoperators": "", "strongselfids": ""]
         XCTAssertEqual(argumentsFor(.default), output)
     }
 
@@ -557,4 +557,9 @@ class ArgumentsTests: XCTestCase {
         let options = try Options(["nospaceoperators": "...,..<"], in: "")
         XCTAssertEqual(options.formatOptions?.noSpaceOperators, ["...", "..<"])
     }
+
+    func testParseStrongSelfIds() throws {
+        let options = try Options(["strongselfids": "ss,sSelf,strongSelf"], in: "")
+        XCTAssertEqual(options.formatOptions?.strongSelfIds, ["ss", "sSelf", "strongSelf"])
+    }
 }

Tests/RulesTests.swift

@@ -8450,6 +8450,31 @@ class RulesTests: XCTestCase {
         testFormatting(for: input, rule: FormatRules.strongifiedSelf)
     }
 
+    func testStrongSelfConvertedToSelfIfDefinedInOptions() {
+        let input = """
+        { [weak self] in
+            guard let strongSelf = self else { return }
+        }
+        """
+        let output = """
+        { [weak self] in
+            guard let self = self else { return }
+        }
+        """
+        let options = FormatOptions(strongSelfIds: ["strongSelf"], swiftVersion: "4.2")
+        testFormatting(for: input, output, rule: FormatRules.strongifiedSelf, options: options)
+    }
+
+    func testStrongSelfNotConvertedToSelfIfNotDefinedInOptions() {
+        let input = """
+        { [weak self] in
+            guard let strongSelf = self else { return }
+        }
+        """
+        let options = FormatOptions(swiftVersion: "4.2")
+        testFormatting(for: input, rule: FormatRules.strongifiedSelf, options: options)
+    }
+
     // MARK: redundantObjc
 
     func testRedundantObjcRemovedFromBeforeOutlet() {

Tests/XCTestManifests.swift

@@ -55,6 +55,7 @@ extension ArgumentsTests {
         ("testParseQuoteArguments", testParseQuoteArguments),
         ("testParseQuotedEscapedN", testParseQuotedEscapedN),
         ("testParseSimpleArguments", testParseSimpleArguments),
+        ("testParseStrongSelfIds", testParseStrongSelfIds),
         ("testParseUnexcludedURLsFileOption", testParseUnexcludedURLsFileOption),
         ("testParseUppercaseIgnoreFileHeader", testParseUppercaseIgnoreFileHeader),
         ("testPreprocessArguments", testPreprocessArguments),
@@ -1470,6 +1471,8 @@ extension RulesTests {
         ("testStripHeader", testStripHeader),
         ("testStrippingSwiftNamespaceDoesNotStripPreviousSwiftNamespaceReferences", testStrippingSwiftNamespaceDoesNotStripPreviousSwiftNamespaceReferences),
         ("testStrippingSwiftNamespaceInOptionalTypeWhenConvertedToSugar", testStrippingSwiftNamespaceInOptionalTypeWhenConvertedToSugar),
+        ("testStrongSelfConvertedToSelfIfDefinedInOptions", testStrongSelfConvertedToSelfIfDefinedInOptions),
+        ("testStrongSelfNotConvertedToSelfIfNotDefinedInOptions", testStrongSelfNotConvertedToSelfIfNotDefinedInOptions),
         ("testsTupleNotUnwrapped", testsTupleNotUnwrapped),
         ("testsTupleOfClosuresNotUnwrapped", testsTupleOfClosuresNotUnwrapped),
         ("testSubscriptFunctionCallNotUnwrapped", testSubscriptFunctionCallNotUnwrapped),