Reload of Remote Text File sometimes deletes lines within the text file

Version of WinSCP: 5.13.7 (also did it in 5.13.6)
OS: Windows 8.1
Remote OS: Linux CentOS 7
Protocol: SFTP
Interface: GUI - Commander
Problem:
When I open a file (on the remote window) which is being written to either by a php program (ie. Error Log), or as an output file by "nohup php <php_script>.php > output.txt &", and I click to reload the file while it is open, it sometimes deletes multiple lines near the end of the file. If I check this file, the overwritten data has been removed from the actual saved data (is not just a display issue). Previous edition I had originally installed did not do this, but I did not record the version number before upgrading.

Self-Troubleshooting Steps Taken - but did not resolve the issue:
· Uninstalled 5.13.6 completely, and then installed 5.13.7
· Changed "Maximum Number of Transfers At The Same Time:" to "1" in settings
· Unselected "Use Multiple Connections For A Single Transfer" in settings

Thank you for looking into this

A.E. wrote:

Version of WinSCP: 5.13.7 (also did it in 5.13.6)
OS: Windows 8.1
Remote OS: Linux CentOS 7
Protocol: SFTP
Interface: GUI - Commander
Problem:
When I open a file (on the remote window) which is being written to either by a php program (ie. Error Log), or as an output file by "nohup php <php_script>.php > output.txt &", and I click to reload the file while it is open, it sometimes deletes multiple lines near the end of the file. If I check this file, the overwritten data has been removed from the actual saved data (is not just a display issue). Previous edition I had originally installed did not do this, but I did not record the version number before upgrading.

Self-Troubleshooting Steps Taken - but did not resolve the issue:
· Uninstalled 5.13.6 completely, and then installed 5.13.7
· Changed "Maximum Number of Transfers At The Same Time:" to "1" in settings
· Unselected "Use Multiple Connections For A Single Transfer" in settings

Thank you for looking into this

Found it worked correctly without this reported issue in WinSCP version 5.9.4 (I tried 5.11.3 next, and that version had the same problem as 5.13.6 and 5.13.7 listed here - I am not sure about the versions between 5.9.4 and 5.11.3, as I did not try those).

A.E. wrote:

Found it worked correctly without this reported issue in WinSCP version 5.9.4 (I tried 5.11.3 next, and that version had the same problem as 5.13.6 and 5.13.7 listed here - I am not sure about the versions between 5.9.4 and 5.11.3, as I did not try those).

Thanks for your report. So can you please try to identify the version that introduced the problem?
You can download all versions of WinSCP from:
https://sourceforge.net/projects/winscp/files/WinSCP/

martin wrote:

Thanks for your report. So can you please try to identify the version that introduced the problem?
You can download all versions of WinSCP from:
https://sourceforge.net/projects/winscp/files/WinSCP/

Hi Martin,

The last version that worked correctly (allowed you to reload text file [ie. refresh the view when open] multiple times without it deleting lines from the file permanently) was 5.9.6.

In 5.10 beta it would allow one reload of text file, then on subsequent reload of file while file was still open, WinSPC would hang. I exited WinSPC by killing the process, re-entered WinSPC, and once I signed in to the remote server the text file that I was using to test with (which was being occasionally written to by "nohup php <php_script>.php > output.txt &") had less lines then when I first opened it before the program hung.

The same behavior happened in 5.10.1 beta, and in 5.10.2 beta WinSPC no longer hung after more than one reload of the text file, but after multiple reloads of the file being written to by "nohup php <php_script>.php > output.txt &", it deleted lines from the file.

I tested in 5.11 and it had the same behavior as 5.10.2 beta. This seems to be the same behavior afterwards upto the current version (although I have only tested the versions listed in this thread - it is only an assumption).

I hope that helps out.

Thanks for your detailed report.
Can you attach session log files from 5.10.2 beta and 5.9.6 showing enough reloads to cause the problem in 5.10.2? Please use "Debug 1" log level.

martin wrote:

Thanks for your detailed report.
Can you attach session log files from 5.10.2 beta and 5.9.6 showing enough reloads to cause the problem in 5.10.2? Please use "Debug 1" log level.

Hi Martin,

I am attaching the Debug 1 log files for:

· 5.9.6 (10 reload / refresh of text file /root/output.txt occasionally written to by "nohup php <php_script>.php > output.txt &" with no data loss on any of the reloads / refreshes of the file opened in the internal editor)

· 5.10.2 beta (10 reload / refresh of the text file /root/output.txt occasionally written to by "nohup php <php_script>.php > output.txt &" with data loss after the 3rd, 8th, and 10th [if my memory serves correct] reload / refresh of the text file opened in the internal editor)

I hope that helps, let me know if you need anything else.

Thanks for your report.

Can you send me an email, so I can send you back a debug version of WinSCP to track the problem? Please include link back to this topic in your email. Also note in this topic that you have sent the email. Thanks.

Ok, email sent to your email with requested info.

Hi Martin,

Ok, I downloaded the debug version of 5.16, and I:
· Turned on Session Logging for Debug 1 (overwrite)
· Exited, and deleted WinSCP logs
· Restarted Debug Version
· Connected to Remote Server
· Opened output.txt (which is being written to by "nohup php <php_script>.php > output.txt &")
· On the third refresh / reload of the file I received the following error:
° "Assertion Failed: FSaving, file forms\Editor.cpp, line 1091"
° Then it gave the following Error "Abnormal Program Termination"
°° The status bar was about 2/3 of the way through the refresh / reload
· Program crashed
· In a non-portable (non-debug) version of WinSCP I checked the output.txt file to see if
lines were missing. The file started with 29902 lines of text, and after the debug
WinSCP program abnormal termination, the output.txt file had 3816 lines of text.

I am attaching the debug log and the session log (Debug 1 level) files

I hope that helps out.

Thanks so much for looking into this.

This bug has been added to the tracker:
https://winscp.net/tracker/1728

Hi Martin,

The last debug version you sent (5.16 9306) seems to have fixed it - I will try it again over the weekend (and post back), but I tried to get it to reproduce the issue for a while and it seems like you have solved the issue.

Thank you so much for taking time to look into this.

I hope you have a great day :)
Aric