Handle module builds without components

module_build_service/scheduler/handlers/modules.py

@@ -267,6 +267,16 @@ def wait(config, session, msg):
     log.debug("Adding dependencies %s into buildroot for module %s" % (dependencies, module_info))
     builder.buildroot_add_repos(dependencies)
 
+    if not build.component_builds:
+        log.info("There are no components in module %r, skipping build" % build)
+        build.transition(config, state="build")
+        session.add(build)
+        session.commit()
+        # Return a KojiRepoChange message so that the build can be transitioned to done
+        # in the repos handler
+        return [module_build_service.messaging.KojiRepoChange(
+            'handlers.modules.wait: fake msg', builder.module_build_tag['name'])]
+
     # If all components in module build will be reused, we don't have to build
     # module-build-macros, because there won't be any build done.
     if attempt_to_reuse_all_components(builder, session, build):

module_build_service/scheduler/handlers/repos.py

@@ -54,7 +54,11 @@ def done(config, session, msg):
         log.info("Ignoring repo regen for already failed %r" % module_build)
         return
 
-    current_batch = module_build.current_batch()
+    # If there are no components in this module build, then current_batch will be empty
+    if not module_build.component_builds:
+        current_batch = []
+    else:
+        current_batch = module_build.current_batch()
 
     # If any in the current batch are still running.. just wait.
     running = [c.state == koji.BUILD_STATES['BUILDING'] for c in current_batch]
@@ -74,7 +78,7 @@ def done(config, session, msg):
     # logic over in the component handler which should fail the module build
     # first before we ever get here.  This is here as a race condition safety
     # valve.
-    if not good:
+    if module_build.component_builds and not good:
         module_build.transition(config, models.BUILD_STATES['failed'],
                                 "Some components failed to build.")
         session.commit()

module_build_service/scheduler/producer.py

@@ -194,10 +194,13 @@ class MBSProducer(PollingProducer):
                       'the concurrent build threshold being met')
             return
 
-        # Check to see if module builds that are in build state but don't have
-        # any component builds being built can be worked on
-        for module_build in session.query(models.ModuleBuild) \
-                .filter_by(state=models.BUILD_STATES['build']).all():
+        # Check for module builds that are in the build state but don't have any active component
+        # builds. Exclude module builds in batch 0. This is likely a build of a module without
+        # components.
+        module_builds = session.query(models.ModuleBuild).filter(
+            models.ModuleBuild.state == models.BUILD_STATES['build'],
+            models.ModuleBuild.batch > 0).all()
+        for module_build in module_builds:
             # If there are no components in the build state on the module build,
             # then no possible event will start off new component builds.
             # But do not try to start new builds when we are waiting for the

tests/staged_data/python3-no-components.yaml

@@ -0,0 +1,34 @@
+# This module is left empty because python3 is contained in the
+# Platform module of Fedora 27 Modular Server edition.
+
+# Other modules can depend on this empty one so that, when the
+# implementation of python3 is moved out of the Platform module,
+# other modules should not be affected.
+
+document: modulemd
+version: 1
+data:
+    summary: Python programming language, version 3
+    description: >-
+        Python is an interpreted, interactive, object-oriented programming
+        language often compared to Tcl, Perl, Scheme or Java. Python includes
+        modules, classes, exceptions, very high level dynamic data types
+        and dynamic typing. Python supports interfaces to many system calls and
+        libraries, as well as to various windowing systems (X11, Motif, Tk,
+        Mac and MFC).
+
+        Programmers can write new built-in modules for Python in C or C++.
+        Python can be used as an extension language for applications that
+        need a programmable interface.
+    license:
+        module:
+            - MIT
+    dependencies:
+        buildrequires:
+            bootstrap: master
+        requires:
+            platform: master
+    references:
+        community: https://www.python.org/
+        documentation: https://docs.python.org/3/
+        tracker: https://src.fedoraproject.org/modules/python3

tests/test_build/test_build.py

@@ -316,6 +316,33 @@ class TestBuild(unittest.TestCase):
         self.assertEqual(tag_groups, [])
         self.assertEqual(buildroot_groups, [])
 
+    @timed(30)
+    @patch('module_build_service.auth.get_user', return_value=user)
+    @patch('module_build_service.scm.SCM')
+    def test_submit_build_no_components(self, mocked_scm, mocked_get_user, conf_system, dbg):
+        """
+        Tests the build of a module with no components
+        """
+        FakeSCM(mocked_scm, 'python3', 'python3-no-components.yaml',
+                '620ec77321b2ea7b0d67d82992dda3e1d67055b4')
+
+        rv = self.client.post('/module-build-service/1/module-builds/', data=json.dumps(
+            {'branch': 'master', 'scmurl': 'git://pkgs.stg.fedoraproject.org/modules/'
+                'testmodule.git?#68932c90de214d9d13feefbd35246a81b6cb8d49'}))
+
+        data = json.loads(rv.data)
+        module_build_id = data['id']
+
+        msgs = []
+        stop = module_build_service.scheduler.make_simple_stop_condition(db.session)
+        module_build_service.scheduler.main(msgs, stop)
+
+        module_build = models.ModuleBuild.query.filter_by(id=module_build_id).one()
+        # Make sure no component builds were registered
+        self.assertEqual(len(module_build.component_builds), 0)
+        # Make sure the build is done
+        self.assertEqual(module_build.state, models.BUILD_STATES['ready'])
+
     @timed(30)
     @patch('module_build_service.auth.get_user', return_value=user)
     @patch('module_build_service.scm.SCM')