utl: ensure exception-safe file closure in stream and file handlers

Addresses an issue where utl::OutStreamHandler could cause a crash
(std::terminate) if a file flush or rename failed during destruction
(e.g., due to ENOSPC).

- Added explicit close() methods to OutStreamHandler, InStreamHandler,
  and FileHandler to allow users to handle closure errors explicitly.
- Updated destructors to be exception-safe by catching potential errors
  during implicit closure.
- Added diagnostic logging to std::cerr in destructors to report
  closure failures that would otherwise be suppressed.

Fixes #9252

Signed-off-by: Matt Liberty <mliberty@precisioninno.com>

Author: maliberty

src/utl/include/utl/ScopedTemporaryFile.h

@@ -49,6 +49,7 @@ class OutStreamHandler
   OutStreamHandler(const char* filename, bool binary = false);
   ~OutStreamHandler();
   std::ostream& getStream();
+  void close();
 
  private:
   std::string filename_;
@@ -66,6 +67,7 @@ class InStreamHandler
   InStreamHandler(const char* filename, bool binary = false);
   ~InStreamHandler();
   std::istream& getStream();
+  void close();
 
  private:
   std::string filename_;
@@ -82,6 +84,7 @@ class FileHandler
   FileHandler(const char* filename, bool binary = false);
   ~FileHandler();
   FILE* getFile();
+  void close();
 
  private:
   std::string filename_;

src/utl/src/ScopedTemporaryFile.cpp

@@ -9,6 +9,7 @@
 #include <exception>
 #include <filesystem>
 #include <ios>
+#include <iostream>
 #include <istream>
 #include <memory>
 #include <ostream>
@@ -95,6 +96,19 @@ OutStreamHandler::OutStreamHandler(const char* filename, bool binary)
 }
 
 OutStreamHandler::~OutStreamHandler()
+{
+  try {
+    close();
+  } catch (const std::exception& e) {
+    std::cerr << "Error: close for " << filename_ << " failed: " << e.what()
+              << "\n";
+  } catch (...) {
+    std::cerr << "Error: close for " << filename_
+              << " failed with unknown error\n";
+  }
+}
+
+void OutStreamHandler::close()
 {
   if (stream_) {
     boost::iostreams::close(*buf_);
@@ -105,9 +119,9 @@ OutStreamHandler::~OutStreamHandler()
   if (os_.is_open()) {
     // Any pending output sequence is written to the file.
     os_.close();
+    // If filename_ exists it will be overwritten
+    fs::rename(tmp_filename_, filename_);
   }
-  // If filename_ exists it will be overwritten
-  fs::rename(tmp_filename_, filename_);
 }
 
 std::ostream& OutStreamHandler::getStream()
@@ -144,6 +158,19 @@ InStreamHandler::InStreamHandler(const char* filename, bool binary)
 }
 
 InStreamHandler::~InStreamHandler()
+{
+  try {
+    close();
+  } catch (const std::exception& e) {
+    std::cerr << "Error: close for " << filename_ << " failed: " << e.what()
+              << "\n";
+  } catch (...) {
+    std::cerr << "Error: close for " << filename_
+              << " failed with unknown error\n";
+  }
+}
+
+void InStreamHandler::close()
 {
   if (stream_) {
     boost::iostreams::close(*buf_);
@@ -152,7 +179,6 @@ InStreamHandler::~InStreamHandler()
   }
 
   if (is_.is_open()) {
-    // Any pending output sequence is written to the file.
     is_.close();
   }
 }
@@ -177,13 +203,30 @@ FileHandler::FileHandler(const char* filename, bool binary)
 }
 
 FileHandler::~FileHandler()
+{
+  try {
+    close();
+  } catch (const std::exception& e) {
+    std::cerr << "Error: close for " << filename_ << " failed: " << e.what()
+              << "\n";
+  } catch (...) {
+    std::cerr << "Error: close for " << filename_
+              << " failed with unknown error\n";
+  }
+}
+
+void FileHandler::close()
 {
   if (file_) {
-    // Any unwritten buffered data are flushed to the OS.
-    std::fclose(file_);
+    const bool failed = (std::fclose(file_) != 0);
+    file_ = nullptr;
+    if (failed) {
+      throw std::runtime_error("fclose failed for " + tmp_filename_ + ": "
+                               + strerror(errno));
+    }
+    // If filename_ exists it will be overwritten.
+    fs::rename(tmp_filename_, filename_);
   }
-  // If filename_ exists it will be overwritten.
-  fs::rename(tmp_filename_, filename_);
 }
 
 FILE* FileHandler::getFile()