make package recipe const

So that only package_.d may modify it and it's easier to reload it from
disk in the future.

source/dub/commandline.d

@@ -2513,7 +2513,7 @@ class DustmiteCommand : PackageBuildCommand {
 					if (subp.path.length) {
 						auto sub_path = base_path ~ NativePath(subp.path);
 						auto pack = prj.packageManager.getOrLoadPackage(sub_path);
-						fixPathDependencies(pack.recipe, sub_path);
+						fixPathDependencies(pack.rawRecipe, sub_path);
 						pack.storeInfo(sub_path);
 					} else fixPathDependencies(subp.recipe, base_path);
 			}
@@ -2528,7 +2528,7 @@ class DustmiteCommand : PackageBuildCommand {
 				copyFolderRec(pack.path, dst_path);
 
 				// adjust all path based dependencies
-				fixPathDependencies(pack.recipe, dst_path);
+				fixPathDependencies(pack.rawRecipe, dst_path);
 
 				// overwrite package description file with additional version information
 				pack.storeInfo(dst_path);

source/dub/dub.d

@@ -1241,8 +1241,10 @@ class Dub {
 
 		GeneratorSettings settings = this.makeAppSettings();
 		settings.runArgs = runArgs;
+		// used for compiler commands and for the CWD of the tool itself, or as
+		// base for relative paths.
+		settings.overrideToolWorkingDirectory = path;
 
-		initSubPackage.recipe.buildSettings.workingDirectory = path.toNativeString();
 		template_dub.generateProject("build", settings);
 	}
 
@@ -1293,7 +1295,7 @@ class Dub {
 		if (m_dryRun) return;
 
 		// allow to choose a custom ddox tool
-		auto tool = m_project.rootPackage.recipe.ddoxTool;
+		string tool = m_project.rootPackage.recipe.ddoxTool;
 		if (tool.empty) tool = "ddox";
 
 		auto tool_pack = m_packageManager.getBestPackage(tool);

source/dub/package_.d

@@ -85,6 +85,7 @@ class Package {
 		PackageRecipe m_info;
 		PackageRecipe m_rawRecipe;
 		Package m_parentPackage;
+		ConfigurationInfo m_testConfiguration;
 	}
 
 	/** Constructs a `Package` using an in-memory package recipe.
@@ -219,14 +220,15 @@ class Package {
 	/// ditto
 	@property void version_(Version value) { assert(m_parentPackage is null); m_info.version_ = value.toString(); }
 
-	/** Accesses the recipe contents of this package.
+	/** Accesses the recipe contents of this package. (only loaded once or after
+		reloading)
 
 		The recipe contains any default values and configurations added by DUB.
-		To access the raw user recipe, use the `rawRecipe` property.
+		To access or modify the raw user recipe, use the `rawRecipe` property.
 
 		See_Also: `rawRecipe`
 	*/
-	@property ref inout(PackageRecipe) recipe() inout { return m_info; }
+	@property ref const(PackageRecipe) recipe() const { return m_info; }
 
 	/** Accesses the original package recipe.
 
@@ -236,7 +238,7 @@ class Package {
 
 		See_Also: `recipe`
 	*/
-	@property ref const(PackageRecipe) rawRecipe() const { return m_rawRecipe; }
+	@property ref inout(PackageRecipe) rawRecipe() inout { return m_rawRecipe; }
 
 	/** Returns the path to the package recipe file.
 
@@ -305,7 +307,7 @@ class Package {
 	void storeInfo(NativePath path)
 	const {
 		auto filename = path ~ defaultPackageFilename;
-		writeJsonFile(filename, m_info.toJson());
+		writeJsonFile(filename, m_rawRecipe.toJson());
 	}
 
 	/** Returns the package recipe of a non-path-based sub package.
@@ -448,6 +450,14 @@ class Package {
 		}
 	}
 
+	void addTestConfiguration(ConfigurationInfo config)
+	{
+		assert(m_testConfiguration is ConfigurationInfo.init,
+			"can't call addTestConfiguration twice!");
+		m_info.configurations ~= config;
+		m_testConfiguration = config;
+	}
+
 	/** Returns the selected configuration for a certain dependency.
 
 		If no configuration is specified in the package recipe, null will be

source/dub/project.d

@@ -344,7 +344,7 @@ class Project {
 			writeFile(mainfile, content);
 		}
 
-		rootPackage.recipe.configurations ~= ConfigurationInfo(config, tcinfo);
+		rootPackage.addTestConfiguration(ConfigurationInfo(config, tcinfo));
 
 		return config;
 	}