Refactor isExternalSymbol to perform more general symbol resolution

Author: mattt

Sources/SwiftDoc/Interface.swift

@@ -162,35 +162,21 @@ public final class Interface {
 
     // MARK: -
 
-    /// Whether the symbol with the given qualified name is declared inside this module or not.
-    ///
-    /// Please note that this tool only operates on the syntax tree and does not have a semantic understanding of the
-    /// symbols, so this method might produce false positives.
-    ///
-    ///  - Parameter name: A qualified name of a symbol.
-    ///  - Returns: Whether or not the symbol is external, meaning that it is not declared in the module.
-    public func isExternalSymbol(named name: String) -> Bool {
-        var nameComponents: [String] = name.split(separator: ".").map(String.init).reversed()
-        var path: [String] = []
-        while let nextComponent = nameComponents.popLast() {
-            guard let symbol = findSymbol(named: nextComponent, path: path) else { return true }
-            path.append(symbol.name)
+    public func symbols(named name: String, resolvingTypealiases: Bool) -> [Symbol] {
+        var pathComponents: [String] = []
+        for component in name.split(separator: ".", omittingEmptySubsequences: true) {
+            pathComponents.append("\(component)")
+            guard resolvingTypealiases else { continue }
+
+            if let symbols = symbolsGroupedByQualifiedName[pathComponents.joined(separator: ".")],
+               let symbol = symbols.first(where: { $0.api is Typealias }),
+               let `typealias` = symbol.api as? Typealias,
+               let initializedType = `typealias`.initializedType
+            {
+                pathComponents = (symbol.context.compactMap { ($0 as? Symbol)?.name ?? ($0 as? Extension)?.extendedType }) + [initializedType]
+            }
         }
-        return false
-    }
 
-    private func findSymbol(named name: String, path immutablePath: [String]) -> Symbol? {
-        var path = immutablePath
-        repeat {
-            let fullPath = (path + CollectionOfOne(name)).joined(separator: ".")
-            if let symbol = symbolsGroupedByQualifiedName[fullPath]?.first {
-                guard let typealiasDeclaration = symbol.api as? Typealias, let initializedName = typealiasDeclaration.initializedType else { return symbol }
-                guard !symbol.context.isEmpty else {
-                   return findSymbol(named: initializedName, path: [])
-                }
-                return findSymbol(named: initializedName, path: symbol.context.compactMap { ($0 as? Symbol)?.name ?? ($0 as? Extension)?.extendedType })
-            }
-        } while path.popLast() != nil
-        return nil
+        return symbolsGroupedByQualifiedName[pathComponents.joined(separator: ".")] ?? []
     }
 }

Sources/swift-doc/Subcommands/Generate.swift

@@ -79,7 +79,7 @@ extension SwiftDoc {
         var symbolsByExternalType: [String: [Symbol]] = [:]
         for symbol in module.interface.symbols.filter(symbolFilter) {
           guard let extensionDeclaration = symbol.context.first as? Extension, symbol.context.count == 1 else { continue }
-          guard module.interface.isExternalSymbol(named: extensionDeclaration.extendedType) else { continue }
+          guard module.interface.symbols(named: extensionDeclaration.extendedType, resolvingTypealiases: true).isEmpty else { continue }
           symbolsByExternalType[extensionDeclaration.extendedType, default: []] += [symbol]
         }
         for (typeName, symbols) in symbolsByExternalType {

Tests/SwiftDocTests/InterfaceTypeTests.swift

@@ -291,15 +291,34 @@ final class InterfaceTypeTests: XCTestCase {
         let sourceFile = try SourceFile(file: url, relativeTo: url.deletingLastPathComponent())
         let module = Module(name: "Module", sourceFiles: [sourceFile])
 
-        XCTAssertFalse(module.interface.isExternalSymbol(named: "SomeClass"))
-        XCTAssertFalse(module.interface.isExternalSymbol(named: "SomeClass.InnerObject"))
-        XCTAssertFalse(module.interface.isExternalSymbol(named: "MyClass"))
-        XCTAssertFalse(module.interface.isExternalSymbol(named: "MyClass.InnerObject"))
-        XCTAssertTrue(module.interface.isExternalSymbol(named: "UIGestureRecognizer"))
-        XCTAssertTrue(module.interface.isExternalSymbol(named: "UIGestureRecognizer.State"))
-        XCTAssertTrue(module.interface.isExternalSymbol(named: "ExternalClass"))
-        XCTAssertTrue(module.interface.isExternalSymbol(named: "ExternalClass.State"))
-        XCTAssertTrue(module.interface.isExternalSymbol(named: "SomeClass.ActuallyExternal"))
-        XCTAssertFalse(module.interface.isExternalSymbol(named: "SomeClass.ActuallyInternal"))
+        XCTAssertEqual(module.interface.symbols(named: "SomeClass", resolvingTypealiases: true).first?.name, "SomeClass")
+        XCTAssertEqual(module.interface.symbols(named: "SomeClass", resolvingTypealiases: false).first?.name, "SomeClass")
+
+        XCTAssertEqual(module.interface.symbols(named: "SomeClass.InnerObject", resolvingTypealiases: true).first?.name, "InnerObject")
+        XCTAssertEqual(module.interface.symbols(named: "SomeClass.InnerObject", resolvingTypealiases: false).first?.name, "InnerObject")
+
+        XCTAssertEqual(module.interface.symbols(named: "SomeClass.ActuallyInternal", resolvingTypealiases: true).first?.name, "InnerStruct")
+        XCTAssertEqual(module.interface.symbols(named: "SomeClass.ActuallyInternal", resolvingTypealiases: false).first?.name, "ActuallyInternal")
+
+        XCTAssertEqual(module.interface.symbols(named: "MyClass", resolvingTypealiases: true).first?.name, "SomeClass")
+        XCTAssertEqual(module.interface.symbols(named: "MyClass", resolvingTypealiases: false).first?.name, "MyClass")
+
+        XCTAssertEqual(module.interface.symbols(named: "MyClass.InnerObject", resolvingTypealiases: true).first?.name, "InnerObject")
+        XCTAssertNil(module.interface.symbols(named: "MyClass.InnerObject", resolvingTypealiases: false).first)
+
+        XCTAssertNil(module.interface.symbols(named: "ExternalClass", resolvingTypealiases: true).first)
+        XCTAssertTrue(module.interface.symbols(named: "ExternalClass", resolvingTypealiases: false).first?.api is Typealias)
+
+        XCTAssertNil(module.interface.symbols(named: "ExternalClass.State", resolvingTypealiases: true).first)
+        XCTAssertNil(module.interface.symbols(named: "ExternalClass.State", resolvingTypealiases: false).first)
+
+        XCTAssertNil(module.interface.symbols(named: "SomeClass.ActuallyExternal", resolvingTypealiases: true).first)
+        XCTAssertTrue(module.interface.symbols(named: "SomeClass.ActuallyExternal", resolvingTypealiases: false).first?.api is Typealias)
+
+        XCTAssertNil(module.interface.symbols(named: "UIGestureRecognizer", resolvingTypealiases: true).first)
+        XCTAssertNil(module.interface.symbols(named: "UIGestureRecognizer", resolvingTypealiases: false).first)
+
+        XCTAssertNil(module.interface.symbols(named: "UIGestureRecognizer.State", resolvingTypealiases: true).first)
+        XCTAssertNil(module.interface.symbols(named: "UIGestureRecognizer.State", resolvingTypealiases: false).first)
     }
 }