MAINT,BLD: pin setuptools and refactor where to find it

azure-pipelines.yml

@@ -241,7 +241,7 @@ stages:
             fi
       displayName: 'add gcc 4.8'
     - script: |
-            python3 -m pip install --user --upgrade pip setuptools
+            python3 -m pip install --user --upgrade pip
             python3 -m pip install --user -r test_requirements.txt
             CPPFLAGS='' CC=gcc-4.8 F77=gfortran-5 F90=gfortran-5 \
             python3 runtests.py --debug-info --mode=full -- -rsx --junitxml=junit/test-results.xml

azure-steps-windows.yml

@@ -4,7 +4,7 @@ steps:
     versionSpec: $(PYTHON_VERSION)
     addToPath: true
     architecture: $(PYTHON_ARCH)
-- script: python -m pip install --upgrade pip setuptools wheel
+- script: python -m pip install --upgrade pip
   displayName: 'Install tools'
 - script: python -m pip install -r test_requirements.txt
   displayName: 'Install dependencies; some are optional to avoid test skips'

pyproject.toml

@@ -1,7 +1,7 @@
 [build-system]
 # Minimum requirements for the build system to execute.
 requires = [
-    "setuptools",
+    "setuptools!=49.2.0",
     "wheel",
     "Cython>=0.29.21",  # Note: keep in sync with tools/cythonize.py
 ]

shippable.yml

@@ -1,7 +1,7 @@
 branches:
-    except:
-       - master
-       - maintenance/*
+    only:
+        - master
+        - maintenance/*
 
 language: python
 

test_requirements.txt

@@ -1,4 +1,6 @@
 cython==0.29.21
+wheel
+setuptools!=49.2.0
 hypothesis==5.19.1
 pytest==5.4.3
 pytz==2020.1

tools/pypy-test.sh

@@ -33,7 +33,7 @@ wget -q https://downloads.python.org/pypy/pypy3.6-v7.3.1-linux64.tar.bz2 -O pypy
 mkdir -p pypy3
 (cd pypy3; tar --strip-components=1 -xf ../pypy.tar.bz2)
 pypy3/bin/pypy3 -mensurepip
-pypy3/bin/pypy3 -m pip install --upgrade pip setuptools wheel
+pypy3/bin/pypy3 -m pip install --upgrade pip
 pypy3/bin/pypy3 -m pip install --user -r test_requirements.txt --no-warn-script-location
 
 echo

tools/travis-before-install.sh

@@ -29,7 +29,7 @@ gcc --version
 
 popd
 
-pip install --upgrade pip
+pip install --upgrade pip setuptools!=49.2.0 wheel
 
 # 'setuptools', 'wheel' and 'cython' are build dependencies.  This information
 # is stored in pyproject.toml, but there is not yet a standard way to install
@@ -41,7 +41,7 @@ pip install --upgrade pip
 # A specific version of cython is required, so we read the cython package
 # requirement using `grep cython test_requirements.txt` instead of simply
 # writing 'pip install setuptools wheel cython'.
-pip install setuptools wheel `grep cython test_requirements.txt`
+pip install `grep cython test_requirements.txt`
 
 if [ -n "$DOWNLOAD_OPENBLAS" ]; then
   pwd