modules: Don't run infinitely when enabling dependent modules and mod…

…ule is not found

This situation shouldn't happen, because the modules were resolved at
this point and all necessary dependencies should be among the active
modules. However, if there is a bug, it's better to throw an error than
to be stuck in an infinite loop.

libdnf5/module/module_sack.cpp

@@ -27,6 +27,7 @@ along with libdnf.  If not, see <https://www.gnu.org/licenses/>.
 
 #include "libdnf5/base/base.hpp"
 #include "libdnf5/base/base_weak.hpp"
+#include "libdnf5/common/exception.hpp"
 #include "libdnf5/module/module_errors.hpp"
 #include "libdnf5/module/module_item.hpp"
 #include "libdnf5/module/module_query.hpp"
@@ -425,7 +426,9 @@ void ModuleSack::Impl::enable_dependent_modules() {
     }
 
     // While there are some modules to enable, search for corresponding active module items and enable them + process their dependencies
-    while (!modules_to_enable.empty()) {
+    bool new_modules_to_enable = true;
+    while (new_modules_to_enable && !modules_to_enable.empty()) {
+        new_modules_to_enable = false;
         for (const auto & active_module : active_modules) {
             const auto & module_name = active_module.second->get_name();
             const auto & module_stream = active_module.second->get_stream();
@@ -441,6 +444,7 @@ void ModuleSack::Impl::enable_dependent_modules() {
                 for (const auto & dependency : active_module.second->get_module_dependencies()) {
                     try {
                         if (module_db->get_status(dependency.get_module_name()) == ModuleStatus::AVAILABLE) {
+                            new_modules_to_enable = true;
                             modules_to_enable.emplace(dependency.get_module_name(), dependency.get_streams());
                         }
                     } catch (NoModuleError &) {
@@ -450,6 +454,8 @@ void ModuleSack::Impl::enable_dependent_modules() {
             }
         }
     }
+    libdnf_assert(
+        modules_to_enable.empty(), "Some enabled modules or their dependencies were not found among active modules.");
 }