Add mypy tox env

Add a "mypy" tox environment which runs mypy
type checking against Cinder code.

Taken from Stephen Finucane's Nova work at
https://review.opendev.org/#/c/676208/

Added "show_error_codes" and "pretty" options.

Generates an html report in ./mypy-report/

This adds stubs for oslo.i18n, so that _() calls
are annotated as intended.  It may be possible to
do this with less .pyi files carried along here.

Change-Id: I2589d22c1f16f2e177d34730a520591743c0c1e3

.gitignore

@@ -27,6 +27,7 @@ instances
 keeper
 keys
 local_settings.py
+mypy-report
 tools/lintstack.head.py
 tools/pylint_exceptions
 tags

cinder/tests/stubs/oslo_i18n/__init__.pyi

@@ -0,0 +1,8 @@
+# Stubs for oslo_i18n (Python 3)
+#
+# NOTE: This dynamically typed stub was automatically generated by stubgen.
+
+from ._factory import *
+from ._gettextutils import *
+from ._lazy import *
+from ._translate import *

cinder/tests/stubs/oslo_i18n/_factory.pyi

@@ -0,0 +1,24 @@
+# Stubs for oslo_i18n._factory (Python 3)
+#
+# NOTE: This dynamically typed stub was automatically generated by stubgen.
+
+from typing import Any, Optional
+
+class TranslatorFactory:
+    domain: Any = ...
+    localedir: Any = ...
+    def __init__(self, domain: Any, localedir: Optional[Any] = ...) -> None: ...
+    @property
+    def primary(self) -> ty.Callable[str]: ...
+    @property
+    def contextual_form(self): ...
+    @property
+    def plural_form(self): ...
+    @property
+    def log_info(self): ...
+    @property
+    def log_warning(self): ...
+    @property
+    def log_error(self): ...
+    @property
+    def log_critical(self): ...

cinder/tests/stubs/oslo_i18n/_gettextutils.pyi

@@ -0,0 +1,8 @@
+# Stubs for oslo_i18n._gettextutils (Python 3)
+#
+# NOTE: This dynamically typed stub was automatically generated by stubgen.
+
+from typing import Any
+
+def install(domain: Any) -> None: ...
+def get_available_languages(domain: Any): ...

cinder/tests/stubs/oslo_i18n/_i18n.pyi

@@ -0,0 +1,4 @@
+# Stubs for oslo_i18n._i18n (Python 3)
+#
+# NOTE: This dynamically typed stub was automatically generated by stubgen.
+

cinder/tests/stubs/oslo_i18n/_lazy.pyi

@@ -0,0 +1,5 @@
+# Stubs for oslo_i18n._lazy (Python 3)
+#
+# NOTE: This dynamically typed stub was automatically generated by stubgen.
+
+def enable_lazy(enable: bool = ...) -> None: ...

cinder/tests/stubs/oslo_i18n/_locale.pyi

@@ -0,0 +1,7 @@
+# Stubs for oslo_i18n._locale (Python 3)
+#
+# NOTE: This dynamically typed stub was automatically generated by stubgen.
+
+from typing import Any
+
+def get_locale_dir_variable_name(domain: Any): ...

cinder/tests/stubs/oslo_i18n/_message.pyi

@@ -0,0 +1,16 @@
+# Stubs for oslo_i18n._message (Python 3)
+#
+# NOTE: This dynamically typed stub was automatically generated by stubgen.
+
+import six
+from typing import Any, Optional
+
+CONTEXT_SEPARATOR: str
+LOG: Any
+
+class Message(six.text_type):
+    def __new__(cls, msgid: Any, msgtext: Optional[Any] = ..., params: Optional[Any] = ..., domain: str = ..., has_contextual_form: bool = ..., has_plural_form: bool = ..., *args: Any): ...
+    def translation(self, desired_locale: Optional[Any] = ...): ...
+    def __mod__(self, other: Any): ...
+    def __add__(self, other: Any) -> None: ...
+    def __radd__(self, other: Any): ...

cinder/tests/stubs/oslo_i18n/_translate.pyi

@@ -0,0 +1,7 @@
+# Stubs for oslo_i18n._translate (Python 3)
+#
+# NOTE: This dynamically typed stub was automatically generated by stubgen.
+
+from typing import Any, Optional
+
+def translate(obj: Any, desired_locale: Optional[Any] = ...): ...

cinder/tests/stubs/oslo_i18n/fixture.pyi

@@ -0,0 +1,29 @@
+# Stubs for oslo_i18n.fixture (Python 3)
+#
+# NOTE: This dynamically typed stub was automatically generated by stubgen.
+
+import fixtures
+import gettext
+from typing import Any, Optional
+
+class Translation(fixtures.Fixture):
+    domain: Any = ...
+    def __init__(self, domain: str = ...) -> None: ...
+    def lazy(self, msg: Any): ...
+    def immediate(self, msg: Any): ...
+
+class ToggleLazy(fixtures.Fixture):
+    def __init__(self, enabled: Any) -> None: ...
+    def setUp(self) -> None: ...
+
+class _PrefixTranslator(gettext.NullTranslations):
+    prefix: Any = ...
+    def __init__(self, fp: Optional[Any] = ..., prefix: str = ...) -> None: ...
+    def gettext(self, message: Any): ...
+    def ugettext(self, message: Any): ...
+
+class PrefixLazyTranslation(fixtures.Fixture):
+    languages: Any = ...
+    locale: Any = ...
+    def __init__(self, languages: Optional[Any] = ..., locale: Optional[Any] = ...) -> None: ...
+    def setUp(self): ...

cinder/tests/stubs/oslo_i18n/log.pyi

@@ -0,0 +1,12 @@
+# Stubs for oslo_i18n.log (Python 3)
+#
+# NOTE: This dynamically typed stub was automatically generated by stubgen.
+
+from logging import handlers
+from typing import Any, Optional
+
+class TranslationHandler(handlers.MemoryHandler):
+    locale: Any = ...
+    def __init__(self, locale: Optional[Any] = ..., target: Optional[Any] = ...) -> None: ...
+    def setFormatter(self, fmt: Any) -> None: ...
+    def emit(self, record: Any) -> None: ...

lower-constraints.txt

@@ -52,6 +52,7 @@ Mako==1.0.7
 MarkupSafe==1.1.0
 mock==2.0.0
 msgpack==0.5.6
+mypy==0.761
 netaddr==0.7.19
 netifaces==0.10.7
 networkx==2.1.0

mypy-files.txt

@@ -0,0 +1,3 @@
+cinder/i18n.py
+cinder/manager.py
+cinder/volume/__init__.py

setup.cfg

@@ -117,3 +117,15 @@ storpool =
 datera =
     dfs-sdk>=1.2.25 # Apache-2.0
 
+
+[mypy]
+show_column_numbers = true
+show_error_context = true
+ignore_missing_imports = true
+follow_imports = skip
+incremental = true
+check_untyped_defs = true
+warn_unused_ignores = true
+show_error_codes = true
+pretty = true
+html_report = mypy-report

test-requirements.txt

@@ -23,3 +23,5 @@ bandit==1.6.0 # Apache-2.0
 doc8>=0.6.0 # Apache-2.0
 reno>=3.1.0 # Apache-2.0
 Pygments>=2.2.0 # BSD license
+
+mypy>=0.761 # MIT

tools/mypywrap.sh

@@ -0,0 +1,24 @@
+#!/bin/sh
+#
+# A wrapper around mypy that allows us to specify what files to run 'mypy' type
+# checks on. Intended to be invoked via tox:
+#
+#   tox -e mypy
+#
+# Eventually this should go away once we have either converted everything or
+# converted enough and ignored [1] the rest.
+#
+# [1] http://mypy.readthedocs.io/en/latest/config_file.html#per-module-flags
+
+ROOT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
+
+export MYPYPATH=$ROOT_DIR/../cinder/tests/stubs/
+
+if [ $# -eq 0 ]; then
+    # if no arguments provided, use the standard converted lists
+    lines=$(grep -v '#' $ROOT_DIR/../mypy-files.txt)
+    python -m mypy ${lines[@]}
+else
+    # else test what the user asked us to
+    python -m mypy $@
+fi

tox.ini

@@ -169,6 +169,13 @@ deps = bindep
 commands = bindep {posargs}
 usedevelop = False
 
+[testenv:mypy]
+description =
+  Run type checks.
+envdir = {toxworkdir}/pep8
+commands =
+  bash tools/mypywrap.sh {posargs}
+
 [flake8]
 # Following checks are ignored on purpose.
 #