From a39c7fa343ed741bbb50bc20a993e43433121e88 Mon Sep 17 00:00:00 2001
From: Ernst Hellbar <ernst.hellbar@cern.ch>
Date: Tue, 11 Nov 2025 14:32:35 +0100
Subject: [PATCH] Event Display: catch several filesystem exceptions

---
 .../Base/src/DirectoryLoader.cxx              | 47 +++++++++++++------
 .../src/VisualisationEventROOTSerializer.cxx  |  4 ++
 2 files changed, 37 insertions(+), 14 deletions(-)

diff --git a/EventVisualisation/Base/src/DirectoryLoader.cxx b/EventVisualisation/Base/src/DirectoryLoader.cxx
index 1b0135428806f..f2f5a421c0ef9 100644
--- a/EventVisualisation/Base/src/DirectoryLoader.cxx
+++ b/EventVisualisation/Base/src/DirectoryLoader.cxx
@@ -29,10 +29,15 @@ using namespace o2::event_visualisation;
 deque<string> DirectoryLoader::load(const std::string& path, const std::string& marker, const std::vector<std::string>& ext)
 {
   deque<string> result;
-  for (const auto& entry : std::filesystem::directory_iterator(path)) {
-    if (std::find(ext.begin(), ext.end(), entry.path().extension()) != ext.end()) {
-      result.push_back(entry.path().filename());
+  try {
+    for (const auto& entry : std::filesystem::directory_iterator(path)) {
+      if (std::find(ext.begin(), ext.end(), entry.path().extension()) != ext.end()) {
+        result.push_back(entry.path().filename());
+      }
     }
+  } catch (std::filesystem::filesystem_error const& ex) {
+    LOGF(error, "filesystem problem during DirectoryLoader::load: %s", ex.what());
+    return result;
   }
   // comparison with safety if marker not in the filename (-1+1 gives 0)
   std::sort(result.begin(), result.end(),
@@ -56,7 +61,8 @@ bool DirectoryLoader::canCreateNextFile(const std::vector<std::string>& paths, c
         }
       }
     } catch (std::filesystem::filesystem_error const& ex) {
-      LOGF(info, "filesystem problem: %s", ex.what());
+      LOGF(error, "filesystem problem during DirectoryLoader::canCreateNextFile: %s", ex.what());
+      return false;
     }
   }
 
@@ -87,12 +93,17 @@ bool DirectoryLoader::canCreateNextFile(const std::vector<std::string>& paths, c
 deque<string> DirectoryLoader::load(const std::vector<std::string>& paths, const std::string& marker, const std::vector<std::string>& ext)
 {
   deque<string> result;
-  for (const auto& path : paths) {
-    for (const auto& entry : std::filesystem::directory_iterator(path)) {
-      if (std::find(ext.begin(), ext.end(), entry.path().extension()) != ext.end()) {
-        result.push_back(entry.path().filename());
+  try {
+    for (const auto& path : paths) {
+      for (const auto& entry : std::filesystem::directory_iterator(path)) {
+        if (std::find(ext.begin(), ext.end(), entry.path().extension()) != ext.end()) {
+          result.push_back(entry.path().filename());
+        }
       }
     }
+  } catch (std::filesystem::filesystem_error const& ex) {
+    LOGF(error, "filesystem problem during DirectoryLoader::load: %s", ex.what());
+    return result;
   }
   // comparison with safety if marker not in the filename (-1+1 gives 0)
   std::sort(result.begin(), result.end(),
@@ -135,10 +146,14 @@ std::time_t to_time_t(TP tp)
 int DirectoryLoader::getNumberOfFiles(const std::string& path, std::vector<std::string>& ext)
 {
   int res = 0;
-  for (const auto& entry : std::filesystem::directory_iterator(path)) {
-    if (std::find(ext.begin(), ext.end(), entry.path().extension()) != ext.end()) {
-      res++;
+  try {
+    for (const auto& entry : std::filesystem::directory_iterator(path)) {
+      if (std::find(ext.begin(), ext.end(), entry.path().extension()) != ext.end()) {
+        res++;
+      }
     }
+  } catch (std::filesystem::filesystem_error const& ex) {
+    LOGF(error, "filesystem problem during DirectoryLoader::getNumberOfFiles: %s", ex.what());
   }
   return res;
 }
@@ -160,8 +175,12 @@ std::string DirectoryLoader::getLatestFile(const std::string& path, std::vector<
 
 void DirectoryLoader::removeOldestFiles(const std::string& path, std::vector<std::string>& ext, const int remaining)
 {
-  while (getNumberOfFiles(path, ext) > remaining) {
-    LOGF(info, "removing oldest file in folder: %s : %s", path, getLatestFile(path, ext));
-    filesystem::remove(path + "/" + getLatestFile(path, ext));
+  try {
+    while (getNumberOfFiles(path, ext) > remaining) {
+      LOGF(info, "removing oldest file in folder: %s : %s", path, getLatestFile(path, ext));
+      filesystem::remove(path + "/" + getLatestFile(path, ext));
+    }
+  } catch (std::filesystem::filesystem_error const& ex) {
+    LOGF(error, "filesystem problem during DirectoryLoader::removeOldestFiles: %s", ex.what());
   }
 }
diff --git a/EventVisualisation/DataConverter/src/VisualisationEventROOTSerializer.cxx b/EventVisualisation/DataConverter/src/VisualisationEventROOTSerializer.cxx
index 8c1a84c1bf85e..8480e15ee9772 100644
--- a/EventVisualisation/DataConverter/src/VisualisationEventROOTSerializer.cxx
+++ b/EventVisualisation/DataConverter/src/VisualisationEventROOTSerializer.cxx
@@ -97,6 +97,10 @@ void VisualisationEventROOTSerializer::toFile(const VisualisationEvent& event, L
 {
   std::string fileName = location.fileName();
   TFile f(fileName.c_str(), "recreate");
+  if (f.IsZombie()) {
+    LOGF(error, "Could not create output file %s", fileName.c_str());
+    return;
+  }
 
   saveInt("runNumber", event.mRunNumber);
   saveInt("runType", event.mRunType);