DM-24780: add initial mypy support.

.gitignore

@@ -16,4 +16,5 @@ bin/*
 .pytest_cache/
 .mypy_cache/
 .idea/
-.vscode/
+.vscode/
+mypy.log

.travis.yml

@@ -5,4 +5,7 @@ matrix:
     - python: '3.7'
       install:
       - pip install flake8
-      script: flake8
+      - pip install mypy
+      script:
+      - flake8
+      - cd python && mypy -p lsst.daf.butler

python/SConscript

@@ -0,0 +1,6 @@
+# -*- python -*-
+from lsst.sconsUtils import state
+mypy = state.env.Command("../mypy.log", "lsst/daf/butler",
+                         "cd python && mypy -p lsst.daf.butler 2>&1 | tee -a ../mypy.log")
+
+state.env.Alias("mypy", mypy)

python/lsst/daf/butler/registry/interfaces/_collections.py

@@ -43,7 +43,7 @@
 from .._collectionType import CollectionType
 
 if TYPE_CHECKING:
-    from .database import Database, StaticTablesContext
+    from ._database import Database, StaticTablesContext
 
 
 class MissingCollectionError(Exception):

python/lsst/daf/butler/registry/interfaces/_database.py

@@ -33,6 +33,7 @@
     Any,
     Dict,
     Iterable,
+    Iterator,
     List,
     Optional,
     Sequence,
@@ -47,7 +48,7 @@
 from .._exceptions import ConflictingDefinitionError
 
 
-def _checkExistingTableDefinition(name: str, spec: ddl.TableSpec, inspection: Dict[str, Any]):
+def _checkExistingTableDefinition(name: str, spec: ddl.TableSpec, inspection: List[Dict[str, Any]]):
     """Test that the definition of a table in a `ddl.TableSpec` and from
     database introspection are consistent.
 
@@ -95,7 +96,7 @@ class StaticTablesContext:
 
     def __init__(self, db: Database):
         self._db = db
-        self._foreignKeys = []
+        self._foreignKeys: List[Tuple[sqlalchemy.schema.Table, sqlalchemy.schema.ForeignKeyConstraint]] = []
         self._inspector = sqlalchemy.engine.reflection.Inspector(self._db._connection)
         self._tableNames = frozenset(self._inspector.get_table_names(schema=self._db.namespace))
 
@@ -136,7 +137,8 @@ def addTableTuple(self, specs: Tuple[ddl.TableSpec, ...]) -> Tuple[sqlalchemy.sc
         is just a factory for `type` objects, not an actual type itself,
         we cannot represent this with type annotations.
         """
-        return specs._make(self.addTable(name, spec) for name, spec in zip(specs._fields, specs))
+        return specs._make(self.addTable(name, spec)                     # type: ignore
+                           for name, spec in zip(specs._fields, specs))  # type: ignore
 
 
 class Database(ABC):
@@ -173,8 +175,7 @@ class Database(ABC):
 
     `Database` itself has several underscore-prefixed attributes:
 
-     - ``_cs``: SQLAlchemy objects representing the connection and transaction
-        state.
+     - ``_connection``: SQLAlchemy object representing the connection.
      - ``_metadata``: the `sqlalchemy.schema.MetaData` object representing
         the tables and other schema entities.
 
@@ -188,7 +189,7 @@ def __init__(self, *, origin: int, connection: sqlalchemy.engine.Connection,
         self.origin = origin
         self.namespace = namespace
         self._connection = connection
-        self._metadata = None
+        self._metadata: Optional[sqlalchemy.schema.MetaData] = None
 
     @classmethod
     def makeDefaultUri(cls, root: str) -> Optional[str]:
@@ -299,7 +300,7 @@ def fromConnection(cls, connection: sqlalchemy.engine.Connection, *, origin: int
         raise NotImplementedError()
 
     @contextmanager
-    def transaction(self, *, interrupting: bool = False) -> None:
+    def transaction(self, *, interrupting: bool = False) -> Iterator:
         """Return a context manager that represents a transaction.
 
         Parameters
@@ -326,7 +327,7 @@ def transaction(self, *, interrupting: bool = False) -> None:
             raise
 
     @contextmanager
-    def declareStaticTables(self, *, create: bool) -> StaticTablesContext:
+    def declareStaticTables(self, *, create: bool) -> Iterator[StaticTablesContext]:
         """Return a context manager in which the database's static DDL schema
         can be declared.
 
@@ -702,7 +703,7 @@ def sync(self, table: sqlalchemy.schema.Table, *,
              compared: Optional[Dict[str, Any]] = None,
              extra: Optional[Dict[str, Any]] = None,
              returning: Optional[Sequence[str]] = None,
-             ) -> Tuple[Optional[Dict[str, Any], bool]]:
+             ) -> Tuple[Optional[Dict[str, Any]], bool]:
         """Insert into a table as necessary to ensure database contains
         values equivalent to the given ones.
 
@@ -919,6 +920,7 @@ def insert(self, table: sqlalchemy.schema.Table, *rows: dict, returnIds: bool =
             raise ReadOnlyDatabaseError(f"Attempt to insert into read-only database '{self}'.")
         if not returnIds:
             self._connection.execute(table.insert(), *rows)
+            return None
         else:
             sql = table.insert()
             return [self._connection.execute(sql, row).inserted_primary_key[0] for row in rows]

python/lsst/daf/butler/registry/nameShrinker.py

@@ -23,6 +23,7 @@
 __all__ = ["NameShrinker"]
 
 import hashlib
+from typing import Dict
 
 
 class NameShrinker:
@@ -44,7 +45,7 @@ class NameShrinker:
     def __init__(self, maxLength: int, hashSize: int = 4):
         self.maxLength = maxLength
         self.hashSize = hashSize
-        self._names = {}
+        self._names: Dict[str, str] = {}
 
     def shrink(self, original: str) -> str:
         """Shrink a name and remember the mapping between the original name and

python/lsst/daf/butler/registry/simpleQuery.py

@@ -25,6 +25,7 @@
 
 from typing import (
     Any,
+    ClassVar,
     List,
     Optional,
     Union,
@@ -42,7 +43,8 @@ class Select:
     """Tag class used to indicate that a field should be returned in
     a SELECT query.
     """
-    pass
+
+    Or: ClassVar
 
 
 Select.Or = Union[T, Type[Select]]

python/mypy.ini

@@ -0,0 +1,20 @@
+[mypy]
+warn_unused_configs = True
+namespace_packages = True
+
+[mypy-sqlalchemy.*]
+ignore_missing_imports = True
+
+[mypy-astropy.*]
+ignore_missing_imports = True
+
+[mypy-boto3]
+ignore_missing_imports = True
+
+[mypy-lsst.*]
+ignore_missing_imports = True
+ignore_errors = True
+
+[mypy-lsst.daf.butler.registry.interfaces.*]
+ignore_missing_imports = False
+ignore_errors = False