From 0d169263858d611b2110d988ca3f4ff3477567c3 Mon Sep 17 00:00:00 2001
From: Gary Yendell <gary.yendell@diamond.ac.uk>
Date: Wed, 3 Dec 2025 16:50:19 +0000
Subject: [PATCH] Escape `<` in logging extras so they aren't treated as colour
 tags

---
 src/fastcs/logging/_logging.py | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/src/fastcs/logging/_logging.py b/src/fastcs/logging/_logging.py
index 3dc2ba2fc..2d54e2f01 100644
--- a/src/fastcs/logging/_logging.py
+++ b/src/fastcs/logging/_logging.py
@@ -2,7 +2,7 @@
 import os
 from enum import StrEnum
 from logging import LogRecord
-from typing import TYPE_CHECKING
+from typing import TYPE_CHECKING, Any
 
 from prompt_toolkit.patch_stdout import StdoutProxy
 from pygelf import GelfUdpHandler
@@ -79,7 +79,8 @@ def format_record(record) -> str:
     sep = "<white>,</white> "
     if "extra" in record:
         extras = [
-            format_key_value(k, v)
+            # Escape `<` so Loguru doesn't parse them as format tags
+            format_key_value(k, f"{v}".replace("<", r"\<"))
             for k, v in record["extra"].items()
             if not k.startswith("_")
         ]
@@ -99,7 +100,7 @@ def format_record(record) -> str:
 """
 
 
-def format_key_value(k, v):
+def format_key_value(k: Any, v: Any) -> str:
     return f"<cyan>{k}</cyan><white>=</white><magenta>{v}</magenta>"