Attempt at fixing failing pypy build (#3860)

* Attempt at fixing failing pypy build

* Try using mambaforge

* Debugging

* A different approach to using mambaforge

* Try a separate environment file for pypy

.github/workflows/CI.yml

@@ -130,8 +130,8 @@ jobs:
               -DOPENMM_BUILD_OPENCL_LIB=OFF \
               -DOPENMM_BUILD_OPENCL_TESTS=OFF \
 
-          - name: Linux CPU Pypy 3.7
-            python-version: "3.7.*=*pypy*"
+          - name: Linux CPU Pypy
+            python-version: "pypy"
             os: ubuntu-latest
             OPENCL: false
             cuda-version: ""
@@ -174,12 +174,24 @@ jobs:
 
       - uses: conda-incubator/setup-miniconda@v2
         name: "Prepare base dependencies"
-        if: matrix.os != 'M1-arm64'
+        if: matrix.python-version == 'pypy'
+        with:
+          activate-environment: build
+          environment-file: devtools/ci/gh-actions/conda-envs/build-ubuntu-pypy.yml
+          auto-activate-base: false
+          miniforge-variant: Mambaforge-pypy3
+          use-mamba: true
+
+      - uses: conda-incubator/setup-miniconda@v2
+        name: "Prepare base dependencies"
+        if: matrix.os != 'M1-arm64' && matrix.python-version != 'pypy'
         with:
           python-version: ${{ matrix.python-version }}
           activate-environment: build
           environment-file: devtools/ci/gh-actions/conda-envs/build-${{ matrix.os }}.yml
           auto-activate-base: false
+          miniforge-variant: Mambaforge
+          use-mamba: true
 
       - name: "Install CUDA on Ubuntu (if needed)"
         if: matrix.cuda-version != '' && startsWith(matrix.os, 'ubuntu')

devtools/ci/gh-actions/conda-envs/build-ubuntu-pypy.yml

+name: build
+channels:
+- conda-forge
+- bioconda
+dependencies:
+# build
+- cmake
+- make
+- ccache
+- sysroot_linux-64 2.17
+# host
+- pypy
+- cython
+- swig
+- numpy
+- ocl-icd-system
+- doxygen 1.8.14
+# test
+- pytest
+- pytest-xdist
+- pytest-timeout
+- gromacs 2018.*