Not create empty skeleton dirs for empty variants

Do not create empty skeleton dirs for empty variants which we do for rpm
variants in some phases (some others already have the check):
1. createiso phase
2. extra_files phase
3. gather phase

In addtion to this, compose metadata (composeinfo.json) doesn't include
variant paths which don't exist or are just empty dirs now.

Fixes: #497
Merges: #572
Signed-off-by: Qixiang Wan <qwan@redhat.com>

pungi/metadata.py

@@ -14,6 +14,7 @@
 # along with this program; if not, see <https://gnu.org/licenses/>.
 
 
+import copy
 import os
 import time
 import json
@@ -168,7 +169,18 @@ def write_compose_info(compose):
     compose.log_info("[BEGIN] %s" % msg)
 
     path = compose.paths.compose.metadata("composeinfo.json")
-    ci.dump(path)
+    # make a copy of composeinfo and modify the copy
+    # if any path in variant paths doesn't exist or just an empty
+    # dir, set it to None, then it won't be dumped.
+    ci_copy = copy.deepcopy(ci)
+    for variant in ci_copy.variants.variants.values():
+        for field in variant.paths._fields:
+            field_paths = getattr(variant.paths, field)
+            for arch, dirpath in field_paths.iteritems():
+                dirpath = os.path.join(compose.paths.compose.topdir(), dirpath)
+                if not (os.path.isdir(dirpath) and os.listdir(dirpath)):
+                    field_paths[arch] = None
+    ci_copy.dump(path)
 
     compose.log_info("[DONE ] %s" % msg)
 

pungi/phases/createiso.py

@@ -66,6 +66,8 @@ class CreateisoPhase(PhaseLoggerMixin, PhaseBase):
 
         commands = []
         for variant in self.compose.get_variants(types=["variant", "layered-product", "optional"]):
+            if variant.is_empty:
+                continue
             for arch in variant.arches + ["src"]:
                 skip_iso = get_arch_variant_data(self.compose.conf, "createiso_skip", arch, variant)
                 if skip_iso == [True]:

pungi/phases/extra_files.py

@@ -37,6 +37,8 @@ class ExtraFilesPhase(ConfigGuardedPhase):
     def run(self):
         for arch in self.compose.get_arches() + ["src"]:
             for variant in self.compose.get_variants(arch=arch):
+                if variant.is_empty:
+                    continue
                 cfg = get_arch_variant_data(self.compose.conf, self.name, arch, variant)
                 if cfg:
                     copy_extra_files(self.compose, cfg, arch, variant, self.pkgset_phase.package_sets)

pungi/phases/gather/__init__.py

@@ -75,6 +75,8 @@ class GatherPhase(PhaseBase):
 
         for arch in self.compose.get_arches():
             for variant in self.compose.get_variants(arch=arch):
+                if variant.is_empty:
+                    continue
                 link_files(self.compose, arch, variant,
                            pkg_map[arch][variant.uid],
                            self.pkgset_phase.package_sets,