Include user provided theme-settings.json file in compiled output

Sources/SwiftDocC/Infrastructure/DocumentationBundle.swift

@@ -87,6 +87,9 @@ public struct DocumentationBundle {
     /// Custom HTML file to use as the footer for rendered output.
     public let customFooter: URL?
 
+    /// JSON settings file used to theme renderer output.
+    public let themeSettings: URL?
+
     /// Default syntax highlighting to use for code samples in this bundle.
     @available(*, deprecated, message: "Use 'info.defaultCodeListingLanguage' instead.")
     public var defaultCodeListingLanguage: String? {
@@ -156,7 +159,8 @@ public struct DocumentationBundle {
         markupURLs: [URL],
         miscResourceURLs: [URL],
         customHeader: URL? = nil,
-        customFooter: URL? = nil
+        customFooter: URL? = nil,
+        themeSettings: URL? = nil
     ) {
         self.info = info
         self.baseURL = baseURL
@@ -166,6 +170,7 @@ public struct DocumentationBundle {
         self.miscResourceURLs = miscResourceURLs
         self.customHeader = customHeader
         self.customFooter = customFooter
+        self.themeSettings = themeSettings
         self.rootReference = ResolvedTopicReference(bundleIdentifier: info.identifier, path: "/", sourceLanguage: .swift)
         self.documentationRootReference = ResolvedTopicReference(bundleIdentifier: info.identifier, path: NodeURLGenerator.Path.documentationFolder, sourceLanguage: .swift)
         self.tutorialsRootReference = ResolvedTopicReference(bundleIdentifier: info.identifier, path: NodeURLGenerator.Path.tutorialsFolder, sourceLanguage: .swift)

Sources/SwiftDocC/Infrastructure/DocumentationBundleFileTypes.swift

@@ -76,4 +76,12 @@ public enum DocumentationBundleFileTypes {
     public static func isCustomFooter(_ url: URL) -> Bool {
         return url.lastPathComponent == customFooterFileName
     }
+
+    private static let themeSettingsFileName = "theme-settings.json"
+    /// Checks if a file is `theme-settings.json`.
+    /// - Parameter url: The file to check.
+    /// - Returns: Whether or not the file at `url` is `theme-settings.json`.
+    public static func isThemeSettingsFile(_ url: URL) -> Bool {
+        return url.lastPathComponent == themeSettingsFileName
+    }
 }

Sources/SwiftDocC/Infrastructure/Workspace/DataProviderBundleDiscovery.swift

@@ -66,8 +66,17 @@ extension DocumentationWorkspaceDataProvider where Self: FileSystemProvider {
 
         let customHeader = findCustomHeader(bundleChildren)?.url
         let customFooter = findCustomFooter(bundleChildren)?.url
+        let themeSettings = findThemeSettings(bundleChildren)?.url
 
-        return DocumentationBundle(info: info, symbolGraphURLs: symbolGraphFiles, markupURLs: markupFiles, miscResourceURLs: miscResources, customHeader: customHeader, customFooter: customFooter)
+        return DocumentationBundle(
+            info: info,
+            symbolGraphURLs: symbolGraphFiles,
+            markupURLs: markupFiles,
+            miscResourceURLs: miscResources,
+            customHeader: customHeader,
+            customFooter: customFooter,
+            themeSettings: themeSettings
+        )
     }
 
     /// Performs a shallow search for the first Info.plist file in the given list of files and directories.
@@ -111,6 +120,10 @@ extension DocumentationWorkspaceDataProvider where Self: FileSystemProvider {
     private func findCustomFooter(_ bundleChildren: [FSNode]) -> FSNode.File? {
         return bundleChildren.firstFile { DocumentationBundleFileTypes.isCustomFooter($0.url) }
     }
+
+    private func findThemeSettings(_ bundleChildren: [FSNode]) -> FSNode.File? {
+        return bundleChildren.firstFile { DocumentationBundleFileTypes.isThemeSettingsFile($0.url) }
+    }
 }
 
 fileprivate extension Array where Element == FSNode {

Sources/SwiftDocCUtilities/Action/Actions/Convert/ConvertFileWritingConsumer.swift

@@ -124,6 +124,17 @@ struct ConvertFileWritingConsumer: ConvertOutputConsumer {
         if let customFooter = bundle.customFooter, enableCustomTemplates {
             try injectCustomTemplate(customFooter, identifiedBy: .footer)
         }
+
+        // Copy the `theme-settings.json` file into the output directory if one
+        // is provided. It will override any default `theme-settings.json` file
+        // that the renderer template may already contain.
+        if let themeSettings = bundle.themeSettings {
+            let targetFile = targetFolder.appendingPathComponent(themeSettings.lastPathComponent, isDirectory: false)
+            if fileManager.fileExists(atPath: targetFile.path) {
+                try fileManager.removeItem(at: targetFile)
+            }
+            try fileManager.copyItem(at: themeSettings, to: targetFile)
+        }
     }
 
     func consume(linkableElementSummaries summaries: [LinkDestinationSummary]) throws {

Tests/SwiftDocCTests/Infrastructure/BundleDiscoveryTests.swift

@@ -294,6 +294,9 @@ class BundleDiscoveryTests: XCTestCase {
         // Ensure that `customFooter` is `nil` if no top level `footer.html`
         // file was found in the bundle
         XCTAssertNil(bundle.customFooter)
+        // Ensure that `themeSettings` is `nil` if no `theme-settings.json`
+        // file was found in the bundle
+        XCTAssertNil(bundle.themeSettings)
     }
 
     func testCustomTemplatesFound() throws {
@@ -325,4 +328,36 @@ class BundleDiscoveryTests: XCTestCase {
         // `footer.html` file if one is found in the bundle
         XCTAssertEqual(bundle.customFooter?.lastPathComponent, "footer.html")
     }
+
+    func testThemeSettingsFound() throws {
+        let workspace = Folder(name: "TestBundle.docc", content:
+            allFiles.map { CopyOfFile(original: $0) } + [
+                TextFile(name: "theme-settings.json", utf8Content: """
+                {
+                  "meta": {},
+                  "theme": {
+                    "colors": {
+                      "text": "#ff0000"
+                    }
+                  },
+                  "features": {}
+                }
+                """),
+            ]
+        )
+
+        let tempURL = try createTemporaryDirectory()
+
+        let workspaceURL = try workspace.write(inside: tempURL)
+        let dataProvider = try LocalFileSystemDataProvider(rootURL: workspaceURL)
+
+        let bundles = try dataProvider.bundles(options: BundleDiscoveryOptions())
+
+        XCTAssertEqual(bundles.count, 1)
+        guard let bundle = bundles.first else { return }
+
+        // Ensure that `themeSettings` points to the location of a
+        // `theme-settings.json` file if one is found in the bundle
+        XCTAssertEqual(bundle.themeSettings?.lastPathComponent, "theme-settings.json")
+    }
 }

Tests/SwiftDocCTests/Infrastructure/DocumentationBundleFileTypesTests.swift

@@ -41,4 +41,18 @@ class DocumentationBundleFileTypesTests: XCTestCase {
         XCTAssertTrue(DocumentationBundleFileTypes.isCustomFooter(
             URL(fileURLWithPath: "DocC.docc/footer.html")))
     }
+
+    func testIsThemeSettingsFile() {
+        XCTAssertTrue(DocumentationBundleFileTypes.isThemeSettingsFile(
+            URL(fileURLWithPath: "theme-settings.json")))
+        XCTAssertTrue(DocumentationBundleFileTypes.isThemeSettingsFile(
+            URL(fileURLWithPath: "/a/b/theme-settings.json")))
+
+        XCTAssertFalse(DocumentationBundleFileTypes.isThemeSettingsFile(
+            URL(fileURLWithPath: "theme-settings.txt")))
+        XCTAssertFalse(DocumentationBundleFileTypes.isThemeSettingsFile(
+            URL(fileURLWithPath: "not-theme-settings.json")))
+        XCTAssertFalse(DocumentationBundleFileTypes.isThemeSettingsFile(
+            URL(fileURLWithPath: "/a/theme-settings.json/bar")))
+    }
 }

Tests/SwiftDocCUtilitiesTests/ConvertActionTests.swift

@@ -2498,6 +2498,64 @@ class ConvertActionTests: XCTestCase {
         let expectedOutput = Folder(name: ".docc-build", content: [expectedIndex])
         expectedOutput.assertExist(at: result.outputs[0], fileManager: FileManager.default)
     }
+
+    func testConvertWithThemeSettings() throws {
+        let info = InfoPlist(displayName: "TestConvertWithThemeSettings", identifier: "com.test.example")
+        let index = TextFile(name: "index.html", utf8Content: """
+        <!DOCTYPE html>
+        <html lang="en">
+            <head>
+                <title>Test</title>
+            </head>
+            <body data-color-scheme="auto"><p>hello</p></body>
+        </html>
+        """)
+        let themeSettings = TextFile(name: "theme-settings.json", utf8Content: """
+        {
+          "meta": {},
+          "theme": {
+            "colors": {
+              "text": "#ff0000"
+            }
+          },
+          "features": {}
+        }
+        """)
+        let template = Folder(name: "template", content: [index])
+        let bundle = Folder(name: "TestConvertWithThemeSettings.docc", content: [
+            info,
+            themeSettings,
+        ])
+
+        let tempURL = try createTemporaryDirectory()
+        let targetURL = tempURL.appendingPathComponent("target", isDirectory: true)
+
+        let bundleURL = try bundle.write(inside: tempURL)
+        let templateURL = try template.write(inside: tempURL)
+
+        let dataProvider = try LocalFileSystemDataProvider(rootURL: bundleURL)
+
+        var action = try ConvertAction(
+            documentationBundleURL: bundleURL,
+            outOfProcessResolver: nil,
+            analyze: false,
+            targetDirectory: targetURL,
+            htmlTemplateDirectory: templateURL,
+            emitDigest: false,
+            currentPlatforms: nil,
+            dataProvider: dataProvider,
+            fileManager: FileManager.default,
+            temporaryDirectory: createTemporaryDirectory(),
+            experimentalEnableCustomTemplates: true
+        )
+        let result = try action.perform(logHandle: .standardOutput)
+
+        let expectedOutput = Folder(name: ".docc-build", content: [
+            index,
+            themeSettings,
+        ])
+        expectedOutput.assertExist(at: result.outputs[0], fileManager: FileManager.default)
+    }
 
     private func uniformlyPrintDiagnosticMessages(_ problems: [Problem]) -> String {
         return problems.sorted(by: { (lhs, rhs) -> Bool in