Add more logging to build file

Author: RichardLitt

.github/workflows/deploy-book.yml

@@ -55,10 +55,29 @@ jobs:
     # Build the book
     - name: Build the book
       run: |
-        jupyter-book build --all .
+        echo "Starting Jupyter Book build..."
+        ls -la _build 2>/dev/null || echo "No _build directory yet"
+        jupyter-book build --all . 2>&1 | tee build.log
+        # Check if build succeeded
+        if grep -q "Error reading file" build.log; then
+          echo "❌ Build error detected in output"
+          cat build.log
+          exit 1
+        fi
+        # Verify the build actually created the output directory
+        if [ ! -d "_build/html" ]; then
+          echo "❌ Error: Build failed to create _build/html directory"
+          exit 1
+        fi
+        if [ ! -f "_build/html/index.html" ]; then
+          echo "❌ Error: Build did not create index.html"
+          exit 1
+        fi
+        echo "✅ Build successful - _build/html created"
 
     # Upload the book's HTML as an artifact
     - name: Upload artifact
+      if: success()
       uses: actions/upload-pages-artifact@v3
       with:
         path: "_build/html"