Add Python Space detection and nvcc check - warn user to switch to Docker Space for CUDA extensions

app.py

@@ -22,6 +22,17 @@ def log_startup_health():
     print("STARTUP HEALTH CHECK")
     print("=" * 60)
     import torch
+    import os
+    
+    is_docker = os.path.exists('/.dockerenv') or os.path.exists('/proc/self/cgroup') and 'docker' in open('/proc/self/cgroup').read()
+    is_python_space = '/home/user/.pyenv' in os.environ.get('PATH', '') or os.path.exists('/home/user/.pyenv')
+    
+    if is_python_space and not is_docker:
+        print("WARNING: Running on Python Space (managed environment)")
+        print("Python Spaces do NOT have CUDA toolchain (nvcc) - CUDA extensions CANNOT build")
+        print("ACTION REQUIRED: Switch to Docker Space in HF Settings -> Runtime -> Docker")
+        print("Without Docker, CUDA extensions will remain NOT INSTALLED (slow fallback)")
+        print("=" * 60)
     
     if torch.cuda.is_available():
         import config

postBuild

@@ -8,6 +8,15 @@ echo "Note: This may fail on Python Spaces without nvcc."
 echo "For guaranteed success, switch to Docker Space."
 echo "=========================================="
 
+if ! command -v nvcc &> /dev/null; then
+    echo "ERROR: nvcc (CUDA compiler) not found!"
+    echo "Python Spaces do not provide CUDA toolchain."
+    echo "ACTION REQUIRED: Switch to Docker Space in HF Settings -> Runtime -> Docker"
+    echo "Docker Space includes nvcc and can build CUDA extensions."
+    exit 1
+fi
+
+echo "nvcc found: $(nvcc --version | head -n 1)"
 pip install pybind11 || {
     echo "WARNING: pybind11 installation failed"
 }