node.pyi: Add type annotations for the node module

This does not contain all the possible needed annotations, but just
enough to have mypy pass.

3 files changed, 31 insertions, 7 deletions

diff --git a/setup.cfg b/setup.cfg
index 55c25ce7b..f2ae3c316 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -31,11 +31,6 @@ warn_no_return = True
 [mypy-copyreg,grpc,pluginbase,psutil,py,pyroaring,pytest,_pytest.*,ruamel]
 ignore_missing_imports=True
 
-# Ignore missing stubs for Cythonized modules.
-# In future, these should be re-enabled by writing stubs for them.
-[mypy-buildstream.node]
-ignore_missing_imports=True
-
 # Ignore issues with generated files and vendored code
 [mypy-buildstream._protos.*,buildstream._version]
 ignore_errors = True
diff --git a/src/buildstream/element.py b/src/buildstream/element.py
index 4a29fd8f2..4995f1f37 100644
--- a/src/buildstream/element.py
+++ b/src/buildstream/element.py
@@ -780,7 +780,7 @@ class Element(Plugin):
         """
         self._stage_sources_in_sandbox(sandbox, directory)
 
-    def get_public_data(self, domain: str) -> "MappingNode[Any, Any]":
+    def get_public_data(self, domain: str) -> "MappingNode[Node]":
         """Fetch public data on this element
 
         Args:
@@ -805,7 +805,7 @@ class Element(Plugin):
 
         return data
 
-    def set_public_data(self, domain: str, data: "MappingNode[Any, Any]") -> None:
+    def set_public_data(self, domain: str, data: "MappingNode[Node]") -> None:
         """Set public data on this element
 
         Args:
diff --git a/src/buildstream/node.pyi b/src/buildstream/node.pyi
new file mode 100644
index 000000000..57083602c
--- /dev/null
+++ b/src/buildstream/node.pyi
@@ -0,0 +1,29 @@
+from typing import Generic, List, Mapping, Optional, Sequence, TypeVar
+
+from ._project import Project
+
+TNode = TypeVar("TNode", bound="Node")
+TValidNodeValue = TypeVar("TValidNodeValue", int, str, bool, Mapping, Sequence)
+
+class ProvenanceInformation: ...
+
+class Node:
+    def clone(self) -> "Node": ...
+
+class MappingNode(Node, Generic[TNode]):
+    def __init__(self, file_index: int, line: int, column: int, value: Mapping[str, TValidNodeValue]) -> None: ...
+    def clone(self) -> MappingNode[TNode]: ...
+    def get_str_list(self, key: str, default: List[str] = None) -> List[str]: ...
+
+class ScalarNode(Node):
+    def as_str(self) -> str: ...
+    def clone(self) -> "ScalarNode": ...
+
+class SequenceNode(Node, Generic[TNode]):
+    def as_str_list(self) -> List[str]: ...
+    def clone(self) -> "SequenceNode[TNode]": ...
+
+def _assert_symbol_name(
+    symbol_name: str, purpose: str, *, ref_node: Optional[Node] = None, allow_dashes: bool = True
+) -> None: ...
+def _new_synthetic_file(filename: str, project: Optional[Project] = None) -> MappingNode[TNode]: ...