Merge #1395 Reuse the latest module build found.

module_build_service/utils/reuse.py

@@ -94,6 +94,10 @@ def get_reusable_module(db_session, module):
     previous_module_build = None
 
     base_mmds = get_base_module_mmds(db_session, mmd)["ready"]
+    # Sort the base_mmds based on the stream version, higher version first.
+    base_mmds.sort(
+        key=lambda mmd: models.ModuleBuild.get_stream_version(mmd.get_stream_name(), False),
+        reverse=True)
     for base_mmd in base_mmds:
         mbs_xmd = mmd.get_xmd()["mbs"]
         if base_mmd.get_module_name() not in mbs_xmd["buildrequires"]:

tests/test_utils/test_utils.py

@@ -26,6 +26,7 @@ from shutil import copyfile, rmtree
 from datetime import datetime
 from werkzeug.datastructures import FileStorage
 from mock import patch
+from sqlalchemy.orm.session import make_transient
 from module_build_service.utils.general import load_mmd_file, mmd_to_str
 import module_build_service.utils
 import module_build_service.scm
@@ -1614,3 +1615,66 @@ class TestUtilsModuleReuse:
         assert build_module.reused_module
         assert reusable_module.id == build_module.reused_module_id
         assert reusable_module.id == reused_module.id
+
+    @patch(
+        "module_build_service.config.Config.allow_only_compatible_base_modules",
+        new_callable=mock.PropertyMock, return_value=False
+    )
+    def test_get_reusable_module_use_latest_build(self, cfg, db_session):
+        """
+        Test that the `get_reusable_module` tries to reuse the latest module in case when
+        multiple modules can be reused.
+        """
+        # Set "fedora" virtual stream to platform:f28.
+        platform_f28 = db_session.query(models.ModuleBuild).filter_by(name="platform").one()
+        mmd = platform_f28.mmd()
+        xmd = mmd.get_xmd()
+        xmd["mbs"]["virtual_streams"] = ["fedora"]
+        mmd.set_xmd(xmd)
+        platform_f28.modulemd = mmd_to_str(mmd)
+        platform_f28.update_virtual_streams(db_session, ["fedora"])
+
+        # Create platform:f29 with "fedora" virtual stream.
+        mmd = load_mmd(read_staged_data("platform"))
+        mmd = mmd.copy("platform", "f29")
+        xmd = mmd.get_xmd()
+        xmd["mbs"]["virtual_streams"] = ["fedora"]
+        mmd.set_xmd(xmd)
+        platform_f29 = module_build_service.utils.import_mmd(db_session, mmd)[0]
+
+        # Create another copy of `testmodule:master` which should be reused, because its
+        # stream version will be higher than the previous one. Also set its buildrequires
+        # to platform:f29.
+        latest_module = db_session.query(models.ModuleBuild).filter_by(
+            name="testmodule").filter_by(state=models.BUILD_STATES["ready"]).one()
+        # This is used to clone the ModuleBuild SQLAlchemy object without recreating it from
+        # scratch.
+        db_session.expunge(latest_module)
+        make_transient(latest_module)
+
+        # Change the platform:f28 buildrequirement to platform:f29 and recompute the build_context.
+        mmd = latest_module.mmd()
+        xmd = mmd.get_xmd()
+        xmd["mbs"]["buildrequires"]["platform"]["stream"] = "f29"
+        mmd.set_xmd(xmd)
+        latest_module.modulemd = mmd_to_str(mmd)
+        latest_module.build_context = module_build_service.models.ModuleBuild.contexts_from_mmd(
+            latest_module.modulemd
+        ).build_context
+        latest_module.buildrequires = [platform_f29]
+
+        # Set the `id` to None, so new one is generated by SQLAlchemy.
+        latest_module.id = None
+        db_session.add(latest_module)
+        db_session.commit()
+
+        module = db_session.query(models.ModuleBuild)\
+                           .filter_by(name="testmodule")\
+                           .filter_by(state=models.BUILD_STATES["build"])\
+                           .one()
+        db_session.commit()
+
+        reusable_module = module_build_service.utils.get_reusable_module(
+            db_session, module)
+
+        assert reusable_module.id == latest_module.id