Address review comments

Author: C-Achard

dlclivegui/cameras/backends/gentl_backend.py

@@ -372,6 +372,7 @@ def open(self) -> None:
             ns["cti_file"] = str(cti_files[0])  # best effort
 
         if not loaded:
+            self._harvester = None
             raise RuntimeError(
                 "No GenTL producer (.cti) could be loaded.\n\n"
                 f"Resolved CTIs: {cti_files}\n"
@@ -384,6 +385,7 @@ def open(self) -> None:
         self._harvester.update()
 
         if not self._harvester.device_info_list:
+            self._harvester = None
             raise RuntimeError(
                 "No GenTL cameras detected via Harvesters after loading producers.\n\n"
                 f"Loaded CTIs: {loaded}\n"

dlclivegui/cameras/backends/utils/gentl_discovery.py

@@ -174,7 +174,7 @@ def _add_candidate(path: str, reason_ctx: str) -> None:
     for entry in env_entries:
         norm_entry = _normalize_path(entry)
         p = Path(norm_entry)
-        if p.is_file() and p.suffix.lower() == ".cti":
+        if p.is_file():  # let _add_candidate check .cti extension and existence
             _add_candidate(norm_entry, "env:file")
         elif p.is_dir():
             for f in _iter_cti_files_in_dir(norm_entry, recursive=recursive_env_search):
@@ -227,7 +227,16 @@ def choose_cti_files(
         return []
 
     if policy == GenTLDiscoveryPolicy.NEWEST:
-        cand_sorted = sorted(cand, key=lambda p: Path(p).stat().st_mtime if Path(p).exists() else 0.0, reverse=True)
+
+        def _newest_mtime(p: str) -> float:
+            try:
+                if not Path(p).exists():
+                    return 0.0
+                return Path(p).stat().st_mtime
+            except OSError:
+                return 0.0
+
+        cand_sorted = sorted(cand, key=_newest_mtime, reverse=True)
         return cand_sorted[:max_files]
 
     if policy == GenTLDiscoveryPolicy.FIRST:

tests/cameras/backends/test_gentl_backend.py

@@ -2,7 +2,6 @@
 from __future__ import annotations
 
 import os
-import time
 import types
 from pathlib import Path
 
@@ -655,9 +654,12 @@ def test_choose_cti_files_newest_policy(tmp_path):
     old = _make_cti(tmp_path, "Old.cti")
     new = _make_cti(tmp_path, "New.cti")
 
-    # Ensure distinct mtimes
-    time.sleep(0.01)
+    # Ensure distinct mtimes (platform agnostic)
     new.write_text("dummy2", encoding="utf-8")
+    old_stat = old.stat()
+    new_stat = new.stat()
+    if new_stat.st_mtime <= old_stat.st_mtime:
+        os.utime(new, (new_stat.st_atime, old_stat.st_mtime + 1))
 
     selected = choose_cti_files([str(old), str(new)], policy=GenTLDiscoveryPolicy.NEWEST, max_files=1)
     assert len(selected) == 1