pkgset: Allow empty list of modules

This should indicate that it's a modular variant, but there is no
modular content yet. We don't want to treat that as Everything.

The end result will be an empty repository.

Fixes: https://pagure.io/pungi/issue/871
Signed-off-by: Lubomír Sedlář <lsedlar@redhat.com>

pungi/phases/gather/sources/source_comps.py

@@ -39,7 +39,7 @@ class GatherSourceComps(pungi.phases.gather.source.GatherSourceBase):
 
         comps = CompsWrapper(self.compose.paths.work.comps(arch=arch))
 
-        is_modular = variant and not variant.groups and variant.modules
+        is_modular = variant and not variant.groups and variant.modules is not None
         if variant is not None and (variant.groups or variant.type != 'variant' or is_modular):
             # Get packages for a particular variant. We want to skip the
             # filtering if the variant is top-level and has no groups (to use

pungi/phases/gather/sources/source_module.py

@@ -44,7 +44,7 @@ class GatherSourceModule(pungi.phases.gather.source.GatherSourceBase):
         # it is not clear what is semantic of that modulemd section.
         compatible_arches = pungi.arch.get_compatible_arches(arch, multilib=False)
 
-        if variant is not None and variant.modules:
+        if variant is not None and variant.modules is not None:
             variant.arch_mmds.setdefault(arch, {})
 
             # Generate architecture specific modulemd metadata, so we can

pungi/phases/pkgset/sources/source_koji.py

@@ -276,7 +276,7 @@ def populate_global_pkgset(compose, koji_wrapper, path_prefix, event_id):
         if pdc_modules:
             with open(pdc_module_file, 'w') as f:
                 json.dump(pdc_modules, f)
-        if not variant_tags[variant]:
+        if not variant_tags[variant] and variant.modules is None:
             variant_tags[variant].extend(force_list(compose.conf["pkgset_koji_tag"]))
 
     # Add global tag(s) if supplied.

pungi/wrappers/variants.py

@@ -71,7 +71,7 @@ class VariantsXmlParser(object):
             "type": str(variant_node.attrib["type"]),
             "arches": [str(i) for i in variant_node.xpath("arches/arch/text()")],
             "groups": [],
-            "modules": [],
+            "modules": None,
             "environments": [],
             "buildinstallpackages": [],
             "is_empty": bool(variant_node.attrib.get("is_empty", False)),
@@ -110,6 +110,7 @@ class VariantsXmlParser(object):
                     "glob": self._is_true(module_node.attrib.get("glob", "false"))
                 }
 
+                variant_dict["modules"] = variant_dict["modules"] or []
                 variant_dict["modules"].append(module)
 
         for environments_node in variant_node.xpath("environments"):
@@ -283,7 +284,10 @@ class Variant(object):
         return result
 
     def get_modules(self, arch=None, types=None, recursive=False):
-        """Return list of groups, default types is ["self"]"""
+        """Return list of modules, default types is ["self"]"""
+
+        if self.modules is None:
+            return []
 
         types = types or ["self"]
         result = copy.deepcopy(self.modules)

share/variants.dtd

@@ -27,7 +27,7 @@
     uservisible (true|false) #IMPLIED
 >
 
-<!ELEMENT modules (module)+>
+<!ELEMENT modules (module)*>
 
 <!ELEMENT module (#PCDATA)>
 <!ATTLIST module

tests/helpers.py

@@ -39,6 +39,7 @@ class MockVariant(mock.Mock):
         self.arch_mmds = {}
         self.variants = {}
         self.pkgset = mock.Mock(rpms_by_arch={})
+        self.modules = None
 
     def __str__(self):
         return self.uid