From a404be15b9a3d511b2c7ab685db729e9c67b24b2 Mon Sep 17 00:00:00 2001
From: Jan Lindemann <jan@janware.com>
Date: Fri, 10 Apr 2020 12:13:12 +0000
Subject: [PATCH] make, scripts: Add support for static Python typechecking

This commit adds support for static typechecking with mypy.

Notable additions:

  - A new target "check" which does the type checking

  - Py-mods.mk, meant to be included from a directory containing python modules
    in subdirectories, but not being a python module itself. It makes the all
    target depend on check only if PY_RUN_CHECK_AFTER_BUILD is defined and
    true.  That's because pypy is under heavy development, and the Ubuntu 18.04
    version is too old to work for lots of the code.

Signed-off-by: Jan Lindemann <jan@janware.com>
---
 make/py-defs.mk         |  6 +++++-
 make/py-mods.mk         | 14 ++++++++++++++
 make/py-rules.mk        |  5 ++++-
 scripts/python-tools.sh |  3 ++-
 4 files changed, 25 insertions(+), 3 deletions(-)
 create mode 100644 make/py-mods.mk

diff --git a/make/py-defs.mk b/make/py-defs.mk
index 08ab51a4..8d6bbcc4 100644
--- a/make/py-defs.mk
+++ b/make/py-defs.mk
@@ -21,6 +21,8 @@ ifndef PY_PREREQ_BUILD_DIRS
   PY_PREREQ_BUILD_DIRS      := $(shell $(proj_query_cmd) proj-dir $(PY_PREREQ_BUILD))
 endif
 
+PY_MYPY                     ?= mypy --ignore-missing-imports
+
 PY_SRC_PY                   ?= $(wildcard *.py)
 PY_ALL_PY                    = $(PY_SRC_PY)
 
@@ -66,7 +68,8 @@ PY_INSTALLED_REG             = $(PY_INSTALLED_PY) $(PY_INSTALLED_PYC)
 
 PYTHONPATH                  ?= $(call proj_query, pythonpath $(PROJECT) $(PY_PREREQ_RUN))
 #PYTHONPATH                  = $(subst $(space),,$(ENV_PYTHONPATH)$(foreach d,$(PY_MODULE_DIRS),:$(d)))
-export PYTHONPATH
+MYPYPATH                     = $(PYTHONPATH)
+export PYTHONPATH MYPYPATH
 
 # not used anywhere
 #PY_PROJ_MODULE_DIRS        ?= $(wildcard $(foreach subdir,/tools/python /src/python,$(addsuffix $(subdir),$(TOPDIR) $(PY_PREREQ_BUILD_DIRS))))
@@ -84,6 +87,7 @@ echo-py:
 	@echo "PY_SITE_PACKAGES_PATH   = $(PY_SITE_PACKAGES_PATH)"
 	@echo "PY_MODULES              = $(PY_MODULES)"
 	@echo "PYTHONPATH              = $(PYTHONPATH)"
+	@echo "MYPYPATH                = $(MYPYPATH)"
 	@echo "PY_INSTALL_MOD          = $(PY_INSTALL_MOD)"
 	@echo "PY_INSTALL_SUB_MOD      = $(PY_INSTALL_SUB_MOD)"
 	# not used anywhere"
diff --git a/make/py-mods.mk b/make/py-mods.mk
new file mode 100644
index 00000000..14766e62
--- /dev/null
+++ b/make/py-mods.mk
@@ -0,0 +1,14 @@
+include $(JWBDIR)/make/defs.mk
+include $(JWBDIR)/make/py-defs.mk
+include $(JWBDIR)/make/dirs.mk
+include $(JWBDIR)/make/dev-utils.mk
+include $(JWBDIR)/make/py-rules.mk
+
+all:
+install:
+clean:
+distclean:
+
+ifeq ($(PY_RUN_CHECK_AFTER_BUILD),true)
+all: check
+endif
diff --git a/make/py-rules.mk b/make/py-rules.mk
index e3f4ae2c..44179362 100644
--- a/make/py-rules.mk
+++ b/make/py-rules.mk
@@ -3,7 +3,7 @@ all:
 py.clean:
 	$(RM) -f *.done *.pyc *.rep
 	/bin/bash $(JWB_SCRIPT_DIR)/scm.sh clean -f __init__.py
-	$(RM) -rf __pycache__
+	$(RM) -rf __pycache__ .mypy_cache
 
 install-dirs.done:
 	$(INSTALL) -d -m $(PYJWBDIRMODE) -o $(PYJWBDIROWNER) -g $(PYJWBDIRGROUP) $(PY_INSTALL_DIRS)
@@ -28,3 +28,6 @@ else
 $(PY_INSTALL_DIR_PY)/%.pyc: %.pyc
 endif
 	$(INSTALL) -p -m $(PYMODMODE) -o $(PYMODOWNER) -g $(PYMODGROUP) $< $@
+
+check:
+	$(PY_MYPY) $(shell /bin/bash $(JWB_SCRIPT_DIR)/scm.sh ls-files | grep '\.py$$')
diff --git a/scripts/python-tools.sh b/scripts/python-tools.sh
index bc1a0a72..47ba373d 100644
--- a/scripts/python-tools.sh
+++ b/scripts/python-tools.sh
@@ -26,7 +26,8 @@ cmd_create_init()
 	local del="-------------------------- generated by $myname"
 	echo "# >> $del >>"
 	echo "from pkgutil import extend_path"
-	echo "__path__ = extend_path(__path__, __name__)"
+	echo "from typing import Iterable"
+	echo "__path__ = extend_path(__path__, __name__) # type: Iterable[str]"
 	files="$*"
 	for f in $files; do
 		test -d $f && continue