init: Add validation for module defaults

After cloning the repository with defaults, open each file and try to
check if there is more than one definition for the same module. It's not
a problem for the compose process, but consumers of the compose would
get confused and possibly explode. Better alert people early.

Conceptually this should be part of the test phase, but that would mean
waiting for the compose to finish before reporting the error. The
earlier the better.

Signed-off-by: Lubomír Sedlář <lsedlar@redhat.com>

pungi/phases/init.py

@@ -14,17 +14,20 @@
 # along with this program; if not, see <https://gnu.org/licenses/>.
 
 
+import collections
+import glob
 import os
 import shutil
 
 from kobo.shortcuts import run
 
+from pungi import Modulemd
 from pungi.phases.base import PhaseBase
 from pungi.phases.gather import write_prepopulate_file
-from pungi.wrappers.createrepo import CreaterepoWrapper
-from pungi.wrappers.comps import CompsWrapper
-from pungi.wrappers.scm import get_file_from_scm, get_dir_from_scm
 from pungi.util import temp_dir
+from pungi.wrappers.comps import CompsWrapper
+from pungi.wrappers.createrepo import CreaterepoWrapper
+from pungi.wrappers.scm import get_dir_from_scm, get_file_from_scm
 
 
 class InitPhase(PhaseBase):
@@ -55,6 +58,9 @@ class InitPhase(PhaseBase):
         # download module defaults
         if self.compose.has_module_defaults:
             write_module_defaults(self.compose)
+            validate_module_defaults(
+                self.compose.paths.work.module_defaults_dir(create_dir=False)
+            )
 
         # write prepopulate file
         write_prepopulate_file(self.compose)
@@ -170,3 +176,30 @@ def write_module_defaults(compose):
         get_dir_from_scm(scm_dict, tmp_dir, logger=compose._logger)
         compose.log_debug("Writing module defaults")
         shutil.copytree(tmp_dir, compose.paths.work.module_defaults_dir(create_dir=False))
+
+
+def validate_module_defaults(path):
+    """Make sure there are no conflicting defaults. Each module name can only
+    have one default stream.
+
+    :param str path: directory with cloned module defaults
+    """
+    seen_defaults = collections.defaultdict(set)
+    for file in glob.glob(os.path.join(path, "*.yaml")):
+        for mmddef in Modulemd.objects_from_file(file):
+            if not isinstance(mmddef, Modulemd.Defaults):
+                continue
+            seen_defaults[mmddef.peek_module_name()].add(mmddef.peek_default_stream())
+
+    errors = []
+    for module_name, defaults in seen_defaults.items():
+        if len(defaults) > 1:
+            errors.append(
+                "Module %s has multiple defaults: %s"
+                % (module_name, ", ".join(sorted(defaults)))
+            )
+
+    if errors:
+        raise RuntimeError(
+            "There are duplicated module defaults:\n%s" % "\n".join(errors)
+        )

tests/test_initphase.py

@@ -10,6 +10,7 @@ import sys
 
 sys.path.insert(0, os.path.join(os.path.dirname(__file__), ".."))
 
+from pungi import Modulemd
 from pungi.phases import init
 from tests.helpers import DummyCompose, PungiTestCase, touch
 
@@ -333,5 +334,66 @@ class TestWriteVariantComps(PungiTestCase):
         self.assertEqual(comps.write_comps.mock_calls, [])
 
 
+@unittest.skipUnless(Modulemd, "Skipped test, no module support.")
+class TestValidateModuleDefaults(PungiTestCase):
+
+    def _write_defaults(self, defs):
+        for mod_name, streams in defs.items():
+            for stream in streams:
+                mmddef = Modulemd.Defaults.new()
+                mmddef.set_version(1)
+                mmddef.set_module_name(mod_name)
+                mmddef.set_default_stream(stream)
+                mmddef.dump(
+                    os.path.join(self.topdir, "%s-%s.yaml" % (mod_name, stream))
+                )
+
+    def test_valid_files(self):
+        self._write_defaults({"httpd": ["1"], "python": ["3.6"]})
+
+        init.validate_module_defaults(self.topdir)
+
+    def test_duplicated_stream(self):
+        self._write_defaults({"httpd": ["1"], "python": ["3.6", "3.5"]})
+
+        with self.assertRaises(RuntimeError) as ctx:
+            init.validate_module_defaults(self.topdir)
+
+        self.assertIn(
+            "Module python has multiple defaults: 3.5, 3.6", str(ctx.exception)
+        )
+
+    def test_reports_all(self):
+        self._write_defaults({"httpd": ["1", "2"], "python": ["3.6", "3.5"]})
+
+        with self.assertRaises(RuntimeError) as ctx:
+            init.validate_module_defaults(self.topdir)
+
+        self.assertIn("Module httpd has multiple defaults: 1, 2", str(ctx.exception))
+        self.assertIn(
+            "Module python has multiple defaults: 3.5, 3.6", str(ctx.exception)
+        )
+
+    def test_handles_non_defaults_file(self):
+        self._write_defaults({"httpd": ["1"], "python": ["3.6"]})
+        touch(
+            os.path.join(self.topdir, "boom.yaml"),
+            "\n".join(
+                [
+                    "document: modulemd",
+                    "version: 2",
+                    "data:",
+                    "  summary: dummy module",
+                    "  description: dummy module",
+                    "  license:",
+                    "    module: [GPL]",
+                    "    content: [GPL]",
+                ]
+            ),
+        )
+
+        init.validate_module_defaults(self.topdir)
+
+
 if __name__ == "__main__":
     unittest.main()