Merge "Shorten missing module panic message" am: 0fe22f4b

	if module == nil {

		// find all the modules that do exist

		allModuleNames := []string{}

		var allModuleNames []string

		var allVariants []string

		ctx.VisitAllModules(func(m blueprint.Module) {

			allModuleNames = append(allModuleNames, m.(Module).Name()+"("+ctx.ModuleSubDir(m)+")")

			allModuleNames = append(allModuleNames, ctx.ModuleName(m))

			if ctx.ModuleName(m) == name {

				allVariants = append(allVariants, ctx.ModuleSubDir(m))

			}

		})

		sort.Strings(allModuleNames)

		sort.Strings(allVariants)

		panic(fmt.Errorf("failed to find module %q variant %q. All modules:\n  %s",

			name, variant, strings.Join(allModuleNames, "\n  ")))

		if len(allVariants) == 0 {

			panic(fmt.Errorf("failed to find module %q. All modules:\n  %s",

				name, strings.Join(allModuleNames, "\n  ")))

		} else {

			panic(fmt.Errorf("failed to find module %q variant %q. All variants:\n  %s",

				name, variant, strings.Join(allVariants, "\n  ")))

		}

	}

	return TestingModule{module}