[Boost-bugs] [Boost C++ Libraries] #13576: boost filesystem create_directories function fails randomly when accessing to a mapped network drive

Subject: [Boost-bugs] [Boost C++ Libraries] #13576: boost filesystem create_directories function fails randomly when accessing to a mapped network drive
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2018-05-28 15:07:47

#13576: boost filesystem create_directories function fails randomly when accessing
to a mapped network drive
------------------------------+-------------------------
 Reporter:  sergio.anza@…     |      Owner:  Beman Dawes
     Type:  Bugs              |     Status:  new
Milestone:  To Be Determined  |  Component:  filesystem
  Version:  Boost 1.60.0      |   Severity:  Problem
 Keywords:                    |
------------------------------+-------------------------
 When trying to create a folder in a mapped network drive with boost
 filesystem create_directories function, I get random errors of type: "The
 system cannot find the path specified.". By random I mean that sometimes I
 get the error and sometimes I don't.

 And yes, I have checked:

 * It is a valid path.
 * It is not a too long path. In fact, I use windows extended path as
 \?\PATH.
 * The network drive works perfectly, and it is inside our company local
 network (Gigabit ethernet).
 * I have write permissions.
 * There are not unicode characters.

 Below the code (adapted to make it more simple).

 {{{
 #include "boost/filesystem.hpp"
 #include <string>
 #include <chrono>
 #include <thread>
 #include <iostream>

 #define MAX_RETRIES 10
 #define RETRY_TIME 5000 //in millisecond

 namespace fs = boost::filesystem;

 bool createDirectory(const std::string& folderPath)
 {
     //If the function does not succeed to create the directory in first
 place, it will retry after RETRY_TIME miliseconds a maximum number of
 MAX_RETRIES.
     for (unsigned int i=0; i<MAX_RETRIES; i++)
     {
         try
         {
             if (fs::create_directories(fs::path(folderPath)))
             {
                 std::cerr << "Folder created successfully!" << std::endl;
                 return true;
             }
         }
         catch (fs::filesystem_error const & e)
         {
                 std::cerr << "File operation problem with files: " <<
 e.what() <<". Try number: "<<i+1<<std::endl;
         }

         if (i==MAX_RETRIES-1)
         {
             return false;
         }

 std::this_thread::sleep_for(std::chrono::milliseconds(RETRY_TIME));

     }
     return true;
 }
 }}}

 In this example I am trying to create the folder:

 Z:\PRIVATE_FOLDERS\XXX\tests\YYY\ZZZZZ\MMMMMMM\CCCCCC\@mmmm1\@ccccc1\@eeeeeeeee2
 (Z is a network mapped drive):

 And here is the output. Sometimes it works the first time

 {{{
 Folder created successfully!
 }}}

 Sometimes it fails several consecutive times until it works. Magic?

 {{{
 File operation problem with files: "boost::filesystem::create_directories:
 The system cannot find the path specified:
 "\\?\Z:\PRIVATE_FOLDERS\XXX\tests\YYY\ZZZZZ\MMMMMMM\CCCCCC\@mmmm1\@ccccc1\@eeeeeeeee2"".
 try number: 1
 File operation problem with files: "boost::filesystem::create_directories:
 The system cannot find the path specified:
 "\\?\Z:\PRIVATE_FOLDERS\XXX\tests\YYY\ZZZZZ\MMMMMMM\CCCCCC\@mmmm1\@ccccc1\@eeeeeeeee2"".
 try number: 2
 File operation problem with files: "boost::filesystem::create_directories:
 The system cannot find the path specified:
 "\\?\Z:\PRIVATE_FOLDERS\XXX\tests\YYY\ZZZZZ\MMMMMMM\CCCCCC\@mmmm1\@ccccc1\@eeeeeeeee2"".
 try number: 3
 Folder created successfully!
 }}}

 The problem of this implementation is that, a priori there is no way to
 differentiate if the input path is a network drive, or it is a wrong path
 or does not have write permissions. Therefore I need always to spend the
 MAX_RETRIES until it finally fails, with the consequent performance
 penalty.

 Notes:

 * I am on Windows 10
 * Boost version is 1.60 built on VS2015 downloaded from official webpage.
 * I use intel compiler 17 for the rest of the code.

-- 
Ticket URL: <https://svn.boost.org/trac10/ticket/13576>
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