Fix SPI doc build issue (#124)

Author: Kyle-Ye

Package.swift

@@ -17,6 +17,18 @@ func envEnable(_ key: String, default defaultValue: Bool = false) -> Bool {
     }
 }
 
+#if os(macOS)
+// NOTE: #if os(macOS) check is not accurate if we are cross compiling for Linux platform. So we add an env key to specify it.
+let buildForDarwinPlatform = envEnable("OPENSWIFTUI_BUILD_FOR_DARWIN_PLATFORM", default: true)
+#else
+let buildForDarwinPlatform = envEnable("OPENSWIFTUI_BUILD_FOR_DARWIN_PLATFORM")
+#endif
+
+
+// https://github.com/SwiftPackageIndex/SwiftPackageIndex-Server/issues/3061#issuecomment-2118821061
+// By-pass https://github.com/swiftlang/swift-package-manager/issues/7580
+let isSPIDocGenerationBuild = envEnable("SPI_GENERATE_DOCS", default: false)
+
 // MARK: - Env and Config
 
 let isXcodeEnv = Context.environment["__CFBundleIdentifier"] == "com.apple.dt.Xcode"
@@ -112,11 +124,7 @@ if warningsAsErrorsCondition {
 
 // MARK: - [env] OPENGRAPH_LIBRARY_EVOLUTION
 
-#if os(macOS)
-let libraryEvolutionCondition = envEnable("OPENGRAPH_LIBRARY_EVOLUTION", default: true)
-#else
-let libraryEvolutionCondition = envEnable("OPENGRAPH_LIBRARY_EVOLUTION")
-#endif
+let libraryEvolutionCondition = envEnable("OPENGRAPH_LIBRARY_EVOLUTION", default: buildForDarwinPlatform)
 
 if libraryEvolutionCondition {
     // NOTE: -enable-library-evolution will cause module verify failure for `swift build`.
@@ -223,16 +231,6 @@ let package = Package(
     cxxLanguageStandard: .cxx20
 )
 
-
-#if os(macOS)
-// FIXME: Enable it by default will cause non-iOS/macOS Apple OS build fail currently.
-// Add the corresponding tbd file and framework to fix it.
-let attributeGraphCondition = envEnable("OPENGRAPH_ATTRIBUTEGRAPH", default: true)
-#else
-let attributeGraphCondition = envEnable("OPENGRAPH_ATTRIBUTEGRAPH")
-#endif
-let useLocalDeps = envEnable("OPENGRAPH_USE_LOCAL_DEPS")
-
 extension Target {
     func addAGSettings() {
         dependencies.append(
@@ -253,6 +251,10 @@ extension Target {
     }
 }
 
+let useLocalDeps = envEnable("OPENGRAPH_USE_LOCAL_DEPS")
+
+let attributeGraphCondition = envEnable("OPENGRAPH_ATTRIBUTEGRAPH", default: buildForDarwinPlatform && !isSPIDocGenerationBuild)
+
 if attributeGraphCondition {
     let privateFrameworkRepo: Package.Dependency
     if useLocalDeps {