From 0c9f44b940c0d95e2cd558cd2bce27da56bbf693 Mon Sep 17 00:00:00 2001
From: Tobias Edman <tobias@modinedman.se>
Date: Wed, 22 Jul 2026 23:40:23 +0200
Subject: [PATCH] fix: make eclipse-check debug logging lazy and epoch-format
 safe
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blocks_sun() formatted the actor and epoch into an f-string on every
timestep, even when no DEBUG handler was active. On some pykep builds
(observed: conda-forge pykep 2.6.4, osx-arm64) str(pk.epoch) raises
RuntimeError (boost bad_lexical_cast) for epochs at exact minute
boundaries, e.g. str(pk.epoch(60.0 / 86400.0)) — which crashed every
simulation using power devices at the first minute boundary.

Use loguru's lazy opt so formatting only happens when DEBUG is
emitted, and format the epoch through a fallback helper so logging
can never crash the simulation even at DEBUG level.

Verified: paseos/tests 32 passed, 1 pre-existing failure
(thermal_model_test, fails identically on clean master).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
---
 paseos/central_body/central_body.py | 23 ++++++++++++++++++++++-
 1 file changed, 22 insertions(+), 1 deletion(-)

diff --git a/paseos/central_body/central_body.py b/paseos/central_body/central_body.py
index d844525f..b8d0e66e 100644
--- a/paseos/central_body/central_body.py
+++ b/paseos/central_body/central_body.py
@@ -98,7 +98,16 @@ def blocks_sun(self, actor, t: pk.epoch, plot=False) -> bool:
         Returns:
             bool: True if the central body blocks the sun
         """
-        logger.debug(f"Checking whether {actor} is in eclipse at {t}.")
+        # Lazy + safe formatting: this runs every timestep, and
+        # str(pk.epoch) can raise RuntimeError (boost bad_lexical_cast)
+        # on some pykep builds at exact minute boundaries, e.g.
+        # str(pk.epoch(60.0 / 86400.0)). Format only when a DEBUG
+        # handler is active, and never let logging crash the sim.
+        logger.opt(lazy=True).debug(
+            "Checking whether {} is in eclipse at {}.",
+            lambda: actor,
+            lambda: _safe_epoch_str(t),
+        )
 
         # Compute central body position in solar reference frame
         r_central_body_heliocentric, _ = np.array(self._planet.eph(t))
@@ -210,3 +219,15 @@ def _apply_rotation(self, point, epoch: pk.epoch):
         # Rotate point
         q = Quaternion(axis=self._rotation_axis, angle=angle)
         return q.rotate(point)
+
+def _safe_epoch_str(t) -> str:
+    """String representation of a pykep epoch that cannot raise.
+
+    Some pykep builds raise RuntimeError (boost bad_lexical_cast) in
+    str(epoch) for values at exact minute boundaries; fall back to the
+    raw mjd2000 value in that case.
+    """
+    try:
+        return str(t)
+    except RuntimeError:
+        return f"epoch(mjd2000={t.mjd2000!r})"