Fix Docker build on ARM by pre-installing numpy (#1121)

Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>

Author: sbryngelson

.github/Dockerfile

@@ -15,17 +15,17 @@ RUN apt-get update -y && \
     if [ "$TARGET" != "gpu" ]; then \
         apt-get install -y \
             build-essential git make cmake gcc g++ gfortran bc \
-            python3.11 python3.11-venv python3-pip \
+            python3.12 python3.12-venv python3-pip \
             openmpi-bin libopenmpi-dev libfftw3-dev \
             mpich libmpich-dev; \
     else \
         apt-get install -y \
             build-essential git make cmake bc \
-            python3.11 python3.11-venv python3-pip \
+            python3.12 python3.12-venv python3-pip \
             libfftw3-dev \
             openmpi-bin libopenmpi-dev; \
     fi && \
-    update-alternatives --install /usr/bin/python3 python3 /usr/bin/python3.11 2 && \
+    update-alternatives --install /usr/bin/python3 python3 /usr/bin/python3.12 2 && \
     rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*
 
 ENV OMPI_ALLOW_RUN_AS_ROOT=1
@@ -40,6 +40,13 @@ ENV FC=${FC_COMPILER}
 ENV PATH="${COMPILER_PATH}:$PATH"
 ENV LD_LIBRARY_PATH="${COMPILER_LD_LIBRARY_PATH}:${LD_LIBRARY_PATH:-}"
 
+# Pre-install numpy into the venv before mfc.sh runs, as it's required at
+# build time by several dependencies (pandas, cantera, matplotlib, etc.) that
+# may need to compile from source on architectures without pre-built wheels
+RUN python3.12 -m venv /opt/MFC/build/venv && \
+    /opt/MFC/build/venv/bin/pip install --upgrade pip && \
+    /opt/MFC/build/venv/bin/pip install numpy
+
 RUN echo "TARGET=$TARGET CC=$CC_COMPILER FC=$FC_COMPILER" && \
     cd /opt/MFC && \
     if [ "$TARGET" = "gpu" ]; then \

.github/workflows/docker.yml

@@ -54,7 +54,7 @@ jobs:
           TAG="${{ github.event.inputs.tag || github.ref_name }}"
           echo "tag=$TAG" >> $GITHUB_OUTPUT
           echo "TAG=$TAG" >> $GITHUB_ENV
-          git clone --branch "$TAG" --depth 1 https://github.com/MFlowCode/MFC.git mfc
+          git clone --branch "$TAG" --depth 1 ${{ github.server_url }}/${{ github.repository }}.git mfc
 
       - name: Stage
         run: |