From bbfffa7e6f8d6ad50b78d47d5dd3bd20857b939f Mon Sep 17 00:00:00 2001
From: Timofey Titovets <nefelim4ag@gmail.com>
Date: Thu, 9 Oct 2025 20:55:28 +0200
Subject: [PATCH] heater_pc: test template on connect

This allows us to handle template errors early and
show the user visible error output in web ui
Instead of crashing within the reactor.

Signed-off-by: Timofey Titovets <nefelim4ag@gmail.com>
---
 klippy/extras/heater_pc.py | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/klippy/extras/heater_pc.py b/klippy/extras/heater_pc.py
index d0266a5be..eb40cf132 100644
--- a/klippy/extras/heater_pc.py
+++ b/klippy/extras/heater_pc.py
@@ -51,6 +51,8 @@ class HeaterPredictControl:
                 output = self.output
             return output
         heater.set_pc_callback(callback)
+        # Test template
+        self._render(.0)
     def _render(self, eventtime):
         context = self.create_context()
         output = self.template.render(context)