Use placeholder EVR and Arch values

Libsolv does need these, so we have to provide fake ones, not just an
empty string.

re: #5071
https://pulp.plan.io/issues/5071

plugins/pulp_rpm/plugins/importers/yum/pulp_solv.py

@@ -415,13 +415,14 @@ def module_artifacts_conversion(pool, module_solvable, name, evr, arch):
             rpm_solvable.add_deparray(solv.SOLVABLE_REQUIRES, module_solvable.nsvca_rel)
             # Provide: modular-package()
             rpm_solvable.add_deparray(solv.SOLVABLE_PROVIDES, pool.Dep('modular-package()'))
-            # Make the module recommend this artifact too
-            module_solvable.add_deparray(solv.SOLVABLE_RECOMMENDS, rel)
-            _LOGGER.debug('link {mod} <-rec-> {solv}', mod=module_solvable, solv=rpm_solvable)
+            # # Make the module require this artifact too
+            # module_solvable.add_deparray(solv.SOLVABLE_REQUIRES, rel)
+            # _LOGGER.debug('link {mod} <-rec-> {solv}', mod=module_solvable, solv=rpm_solvable)
 
     solvable_name = module_solvable_name(unit)
     solvable.name = solvable_name
-    solvable.evr = ''
+    # there's no reasonable way to construct an EVR, but it has to be set, so use '0-1' (V-R)
+    solvable.evr = '0-1'
 
     arch = unit.get('arch', 'noarch').encode('utf-8')
     solvable.arch = arch
@@ -570,8 +571,10 @@ def module_defaults_unit_to_solvable(solv_repo, unit):
     :rtype: solv.Solvable
     """
     solvable = solv_repo.add_solvable()
-    solvable.evr = ''
-    solvable.arch = ''
+    # there's no reasonable way to construct an EVR, but it has to be set, so use '0-1' (V-R)
+    solvable.evr = '0-1'
+    # a module default has no arch, use 'noarch'
+    solvable.arch = 'noarch'
 
     name = unit.get('name')
     if name is not None:
@@ -859,7 +862,11 @@ def _handle_nothing_provides(self, info):
         if not target_repo:
             return
         dummy = target_repo.add_solvable()
+        dummy.name = 'dummy-provides:{}'.format(str(info.dep))
+        dummy.arch = 'noarch'
+        dummy.evr = '0-1'
         dummy.add_deparray(solv.SOLVABLE_PROVIDES, info.dep)
+        self._pool.createwhatprovides()
         _LOGGER.debug('Created dummy provides: {name}', name=info.dep.str())
 
     def _handle_same_name(self, info, jobs):