Merge branch 'tristan/fix-missing-workspace-artifact-1.2' into 'bst-1.2'

element.py: Reset workspace state if last successful build is missing (1.2)

See merge request BuildStream/buildstream!1329

3 files changed, 54 insertions, 4 deletions

diff --git a/buildstream/element.py b/buildstream/element.py
index 898ff0784..b98675720 100644
--- a/buildstream/element.py
+++ b/buildstream/element.py
@@ -699,9 +699,26 @@ class Element(Plugin):
         old_dep_keys = {}
         workspace = self._get_workspace()
         project = self._get_project()
+        context = self._get_context()
 
         if self.__can_build_incrementally() and workspace.last_successful:
-            old_dep_keys = self.__get_artifact_metadata_dependencies(workspace.last_successful)
+
+            # Try to perform an incremental build if the last successful
+            # build is still in the artifact cache
+            #
+            if self.__artifacts.contains(self, workspace.last_successful):
+                old_dep_keys = self.__get_artifact_metadata_dependencies(workspace.last_successful)
+            else:
+                # Last successful build is no longer in the artifact cache,
+                # so let's reset it and perform a full build now.
+                workspace.prepared = False
+                workspace.last_successful = None
+
+                self.info("Resetting workspace state, last successful build is no longer in the cache")
+
+                # In case we are staging in the main process
+                if utils._is_main_process():
+                    context.get_workspaces().save_config()
 
         for dep in self.dependencies(scope):
             # If we are workspaced, and we therefore perform an
@@ -726,7 +743,7 @@ class Element(Plugin):
                     # In case we are running `bst shell`, this happens in the
                     # main process and we need to update the workspace config
                     if utils._is_main_process():
-                        self._get_context().get_workspaces().save_config()
+                        context.get_workspaces().save_config()
 
             result = dep.stage_artifact(sandbox,
                                         path=path,
diff --git a/tests/integration/workspace.py b/tests/integration/workspace.py
index 102d053fc..e30d54df3 100644
--- a/tests/integration/workspace.py
+++ b/tests/integration/workspace.py
@@ -255,3 +255,36 @@ def test_incremental_configure_commands_run_only_once(cli, tmpdir, datafiles):
     res = cli.run(project=project, args=['build', element_name])
     res.assert_success()
     assert not os.path.exists(os.path.join(workspace, 'prepared-again'))
+
+
+# Test that rebuilding an already built workspaced element does
+# not crash after the last successfully built artifact is removed
+# from the cache
+#
+# A user can remove their artifact cache, or manually remove the
+# artifact with `bst artifact delete`, or BuildStream can delete
+# the last successfully built artifact for this workspace as a
+# part of a cleanup job.
+#
+@pytest.mark.integration
+@pytest.mark.datafiles(DATA_DIR)
+def test_workspace_missing_last_successful(cli, datafiles, integration_cache):
+    project = str(datafiles)
+    workspace = os.path.join(cli.directory, 'workspace')
+    element_name = 'workspace/workspace-mount.bst'
+
+    # Open workspace
+    res = cli.run(project=project, args=['workspace', 'open', element_name, workspace])
+    assert res.exit_code == 0
+
+    # Build first, this will record the last successful build in local state
+    res = cli.run(project=project, args=['build', element_name])
+    assert res.exit_code == 0
+
+    # Remove the artifact from the cache, invalidating the last successful build
+    cache_dir = os.path.join(integration_cache, 'artifacts')
+    cli.remove_artifact_from_cache(project, element_name, cache_dir=cache_dir)
+
+    # Build again, ensure we dont crash just because the artifact went missing
+    res = cli.run(project=project, args=['build', element_name])
+    assert res.exit_code == 0
diff --git a/tests/testutils/runcli.py b/tests/testutils/runcli.py
index 805b1192d..06f3f1c3a 100644
--- a/tests/testutils/runcli.py
+++ b/tests/testutils/runcli.py
@@ -218,8 +218,8 @@ class Cli():
             cache_dir = os.path.join(project, 'cache', 'artifacts')
 
         cache_dir = os.path.join(cache_dir, 'cas', 'refs', 'heads')
-
-        cache_dir = os.path.splitext(os.path.join(cache_dir, 'test', element_name))[0]
+        normal_name = element_name.replace(os.sep, '-')
+        cache_dir = os.path.splitext(os.path.join(cache_dir, 'test', normal_name))[0]
         shutil.rmtree(cache_dir)
 
     # run():