Support building mypycified mypy with PEP517 interface

.github/workflows/test.yml

@@ -120,7 +120,7 @@ jobs:
       if: ${{ matrix.test_mypyc }}
       run: |
         pip install -r test-requirements.txt
-        CC=clang MYPYC_OPT_LEVEL=0 python3 setup.py --use-mypyc build_ext --inplace
+        CC=clang MYPYC_OPT_LEVEL=0 MYPY_USE_MYPYC=1 pip install -e .
     - name: Setup tox environment
       run: tox -e ${{ matrix.toxenv }} --notest
     - name: Test

build-requirements.txt

@@ -1,3 +1,4 @@
+# NOTE: this needs to be kept in sync with the "requires" list in pyproject.toml
 -r mypy-requirements.txt
 types-psutil
 types-setuptools

mypy-requirements.txt

@@ -1,3 +1,4 @@
+# NOTE: this needs to be kept in sync with the "requires" list in pyproject.toml
 typing_extensions>=3.10
 mypy_extensions>=0.4.3
 typed_ast>=1.4.0,<2; python_version<'3.8'

pyproject.toml

@@ -1,7 +1,19 @@
 [build-system]
 requires = [
+    # NOTE: this needs to be kept in sync with mypy-requirements.txt
+    # and build-requirements.txt, because those are both needed for
+    # self-typechecking :/
     "setuptools >= 40.6.2",
     "wheel >= 0.30.0",
+    # the following is from mypy-requirements.txt
+    "typing_extensions>=3.10",
+    "mypy_extensions>=0.4.3",
+    "typed_ast>=1.4.0,<2; python_version<'3.8'",
+    "tomli>=1.1.0; python_version<'3.11'",
+    # the following is from build-requirements.txt
+    "types-psutil",
+    "types-setuptools",
+    "types-typed-ast>=1.5.8,<1.6.0",
 ]
 build-backend = "setuptools.build_meta"
 

setup.py

@@ -79,8 +79,8 @@ def run(self):
 
 USE_MYPYC = False
 # To compile with mypyc, a mypyc checkout must be present on the PYTHONPATH
-if len(sys.argv) > 1 and sys.argv[1] == "--use-mypyc":
-    sys.argv.pop(1)
+if len(sys.argv) > 1 and "--use-mypyc" in sys.argv:
+    sys.argv.remove("--use-mypyc")
     USE_MYPYC = True
 if os.getenv("MYPY_USE_MYPYC", None) == "1":
     USE_MYPYC = True