try with a postbuild file

Author: eatyourpeas

.binder/postBuild

@@ -0,0 +1,15 @@
+#!/bin/bash
+set -euo pipefail
+
+echo "[postBuild] Editable install of local package"
+pip install -e .
+
+echo "[postBuild] Warm up matplotlib font cache"
+python - <<'PY'
+import matplotlib.pyplot as plt  # triggers font cache build
+print("Matplotlib imported; font cache built.")
+PY
+
+echo "[postBuild] Warm up JupyterLab (pre-build static if needed)"
+jupyter lab build --minimize=False >/dev/null 2>&1 || true
+echo "[postBuild] Done"

.binder/requirements.txt

@@ -1 +1,6 @@
-rcpchgrowth[notebook]
+pandas
+matplotlib
+jupyterlab
+ipykernel
+scipy
+python-dateutil

.binder/start

@@ -1,3 +1,10 @@
 #!/bin/bash
-# Start Jupyter in the correct directory
-exec jupyter lab --ContentsManager.root_dir=/home/jovyan
+set -euo pipefail
+echo "[start] Python: $(python -V)"
+echo "[start] rcpchgrowth import test:"
+python - <<'PY'
+import rcpchgrowth, os, sys
+print("rcpchgrowth version:", getattr(rcpchgrowth, "__version__", "?"))
+print("rcpchgrowth path:", rcpchgrowth.__file__)
+PY
+exec jupyter lab --ServerApp.root_dir=/home/jovyan --ServerApp.default_url=/lab