From 4f5c0467e158041bd46c6ce71fe8c6e909171d05 Mon Sep 17 00:00:00 2001
From: Ben Jeffery <ben.jeffery@bdi.ox.ac.uk>
Date: Tue, 29 Aug 2023 18:53:46 +0100
Subject: [PATCH 1/2] Add loading indicator to pages

---
 app.py | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/app.py b/app.py
index a7d72a0..f1537e8 100644
--- a/app.py
+++ b/app.py
@@ -29,7 +29,9 @@
 
 
 def show(page):
-    return pages[page](tsm)
+    yield pn.indicators.LoadingSpinner(value=True, width=50, height=50)
+    content = pages[page](tsm)
+    yield content
 
 
 starting_page = pn.state.session_args.get("page", [b"Overview"])[0].decode()

From 9ee487c5a04b4a36acd3196b464335d468a14d5f Mon Sep 17 00:00:00 2001
From: Ben Jeffery <ben.jeffery@bdi.ox.ac.uk>
Date: Tue, 29 Aug 2023 23:16:26 +0100
Subject: [PATCH 2/2] Add error handling

---
 app.py | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/app.py b/app.py
index f1537e8..3f170f0 100644
--- a/app.py
+++ b/app.py
@@ -1,6 +1,7 @@
 import logging
 import pathlib
 import sys
+import traceback
 
 import panel as pn
 import tskit
@@ -30,7 +31,17 @@
 
 def show(page):
     yield pn.indicators.LoadingSpinner(value=True, width=50, height=50)
-    content = pages[page](tsm)
+    try:
+        content = pages[page](tsm)
+    except Exception as e:
+        error_message = f"An error occurred: {str(e)}"
+        error_traceback = traceback.format_exc().replace("\n", "<br>")
+        error_traceback = f"<pre>{error_traceback}</pre>"
+        error_panel = pn.pane.Markdown(
+            f"## Error\n\n{error_message}\n\n{error_traceback}", style={"color": "red"}
+        )
+        yield error_panel
+        return
     yield content