Add additional keys to workspace config:

* `last_artifact_ref`
* `last_dep_hash`
* replace `last_successful` with `last_digest`

6 files changed, 53 insertions, 24 deletions

diff --git a/src/buildstream/_loader/loader.py b/src/buildstream/_loader/loader.py
index 3b18af691..8aa37298d 100644
--- a/src/buildstream/_loader/loader.py
+++ b/src/buildstream/_loader/loader.py
@@ -452,7 +452,10 @@ class Loader:
         if workspace:
             workspace_node = {"kind": "workspace"}
             workspace_node["path"] = workspace.get_absolute_path()
-            workspace_node["last_successful"] = str(workspace.to_dict().get("last_successful", ""))
+            workspace_dict = workspace.to_dict()
+            workspace_node["last_digest"] = str(workspace_dict.get("last_digest", ""))
+            workspace_node["last_artifact_ref"] = str(workspace_dict.get("last_artifact_ref", ""))
+            workspace_node["last_dep_hash"] = str(workspace_dict.get("last_dep_hash", ""))
             node[Symbol.SOURCES] = [workspace_node]
             skip_workspace = False
 
diff --git a/src/buildstream/_stream.py b/src/buildstream/_stream.py
index 4b8409323..c08fbad1a 100644
--- a/src/buildstream/_stream.py
+++ b/src/buildstream/_stream.py
@@ -926,7 +926,7 @@ class Stream:
 
             if soft:
                 workspace.prepared = False
-                workspace.last_successful = None
+                workspace.last_digest = None
                 self._message(
                     MessageType.INFO, "Reset workspace state for {} at: {}".format(element.name, workspace_path)
                 )
diff --git a/src/buildstream/_workspaces.py b/src/buildstream/_workspaces.py
index 3d50fd9c0..3176482c3 100644
--- a/src/buildstream/_workspaces.py
+++ b/src/buildstream/_workspaces.py
@@ -232,22 +232,36 @@ class WorkspaceProjectCache:
 # An object to contain various helper functions and data required for
 # workspaces.
 #
-# last_successful, path and running_files are intended to be public
-# properties, but may be best accessed using this classes' helper
-# methods.
+# last_digest, last_artifact_ref, last_dep_hash, path and running_files
+# are intended to be public properties, but may be best accessed using
+# this classes' helper methods.
 #
 # Args:
 #    toplevel_project (Project): Top project. Will be used for resolving relative workspace paths.
 #    path (str): The path that should host this workspace
-#    last_successful (str): The key of the last successful build of this workspace
+#    last_digest (str): The key of the last build of this workspace
+#    last_artifact_ref (str): The cache key of the most recent artifact
+#    last_dep_hash (str): The hash of the dependency tree
 #    running_files (dict): A dict mapping dependency elements to files
 #                          changed between failed builds. Should be
 #                          made obsolete with failed build artifacts.
 #
 class Workspace:
-    def __init__(self, toplevel_project, *, last_successful=None, path=None, prepared=False, running_files=None):
+    def __init__(
+        self,
+        toplevel_project,
+        *,
+        last_digest=None,
+        last_artifact_ref=None,
+        last_dep_hash=None,
+        path=None,
+        prepared=False,
+        running_files=None
+    ):
         self.prepared = prepared
-        self.last_successful = last_successful
+        self.last_digest = last_digest
+        self.last_artifact_ref = last_artifact_ref
+        self.last_dep_hash = last_dep_hash
         self._path = path
         self.running_files = running_files if running_files is not None else {}
 
@@ -263,8 +277,12 @@ class Workspace:
     #
     def to_dict(self):
         ret = {"prepared": self.prepared, "path": self._path, "running_files": self.running_files}
-        if self.last_successful is not None:
-            ret["last_successful"] = self.last_successful
+        if self.last_artifact_ref is not None:
+            ret["last_artifact_ref"] = self.last_artifact_ref
+        if self.last_digest is not None:
+            ret["last_digest"] = self.last_digest
+        if self.last_dep_hash is not None:
+            ret["last_dep_hash"] = self.last_dep_hash
         return ret
 
     # from_dict():
@@ -632,7 +650,9 @@ class Workspaces:
         dictionary = {
             "prepared": node.get_bool("prepared", default=False),
             "path": node.get_str("path"),
-            "last_successful": node.get_str("last_successful", default=None),
+            "last_digest": node.get_str("last_digest", default=None),
+            "last_artifact_ref": node.get_str("last_artifact_ref", default=None),
+            "last_dep_hash": node.get_str("last_dep_hash", default=None),
             "running_files": running_files,
         }
         return Workspace.from_dict(self._toplevel_project, dictionary)
diff --git a/src/buildstream/element.py b/src/buildstream/element.py
index 4bd3ae8b3..00b2088e7 100644
--- a/src/buildstream/element.py
+++ b/src/buildstream/element.py
@@ -752,20 +752,20 @@ class Element(Plugin):
         workspace = self._get_workspace()
         context = self._get_context()
 
-        if self.__can_build_incrementally() and workspace.last_successful:
+        if self.__can_build_incrementally() and workspace.last_digest:
 
             # 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):
-                last_successful = Artifact(self, context, strong_key=workspace.last_successful)
+            if self.__artifacts.contains(self, workspace.last_digest):
+                last_digest = Artifact(self, context, strong_key=workspace.last_digest)
                 # Get a dict of dependency strong keys
-                old_dep_keys = last_successful.get_metadata_dependencies()
+                old_dep_keys = last_digest.get_metadata_dependencies()
             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
+                workspace.last_digest = None
 
                 self.info("Resetting workspace state, last successful build is no longer in the cache")
 
@@ -1600,7 +1600,7 @@ class Element(Plugin):
             #
             key = self._get_cache_key()
             workspace = self._get_workspace()
-            workspace.last_successful = key
+            workspace.last_digest = key
             workspace.clear_running_files()
             self._get_context().get_workspaces().save_config()
 
@@ -2408,7 +2408,7 @@ class Element(Plugin):
             # FIXME: ideally we don't have to check this, eventually we would
             # like to get the saved old_ref and apply the new workspace on top
             # to support incremental builds.
-            if [s._key for s in self.__sources] == [workspace.last_successful]:
+            if [s._key for s in self.__sources] == [workspace.last_digest]:
                 prepared = False
 
         if not prepared:
diff --git a/src/buildstream/plugins/sources/workspace.py b/src/buildstream/plugins/sources/workspace.py
index 3d4c93b5c..df62aa51b 100644
--- a/src/buildstream/plugins/sources/workspace.py
+++ b/src/buildstream/plugins/sources/workspace.py
@@ -55,16 +55,22 @@ class WorkspaceSource(Source):
         self.__unique_key = None
         # the digest of the Directory following the import of the workspace
         self.__digest = None
-        # the cache key of the last successful workspace
-        self.__last_successful = None
+        # the cache key of the last workspace build
+        self.__last_digest = None
+        # the ref of the last workspace artifact
+        self.__last_artifact_ref = None
+        # the hash of the last workspace dependency graph
+        self.__last_dep_hash = None
 
     def track(self) -> SourceRef:  # pylint: disable=arguments-differ
         return None
 
     def configure(self, node: MappingNode) -> None:
-        node.validate_keys(["path", "last_successful", "kind"])
+        node.validate_keys(["path", "last_digest", "last_artifact_ref", "last_dep_hash", "kind"])
         self.path = node.get_str("path")
-        self.__last_successful = node.get_str("last_successful")
+        self.__last_digest = node.get_str("last_digest")
+        self.__last_artifact_ref = node.get_str("last_artifact_ref")
+        self.__last_dep_hash = node.get_str("last_dep_hash")
 
     def preflight(self) -> None:
         pass  # pragma: nocover
diff --git a/tests/frontend/workspace.py b/tests/frontend/workspace.py
index 80db8cc98..ec361caf4 100644
--- a/tests/frontend/workspace.py
+++ b/tests/frontend/workspace.py
@@ -873,7 +873,7 @@ def test_list_unsupported_workspace(cli, datafiles, workspace_cfg):
                 "workspaces": {
                     "alpha.bst": {
                         "path": "/workspaces/bravo",
-                        "last_successful": "some_key",
+                        "last_digest": "some_key",
                         "running_files": {"beta.bst": ["some_file"]},
                     }
                 },
@@ -884,7 +884,7 @@ def test_list_unsupported_workspace(cli, datafiles, workspace_cfg):
                     "alpha.bst": {
                         "prepared": False,
                         "path": "/workspaces/bravo",
-                        "last_successful": "some_key",
+                        "last_digest": "some_key",
                         "running_files": {"beta.bst": ["some_file"]},
                     }
                 },