WinMerge
WinMerge Comparison Report can be incorrect
WinMerge Comparison Report inconsistent
WinMerge Does not exist in D D is left.png
Report states that the file does not exist in 'D', but the files for 'D' are listed.
WinMerge Left and middle are identical middle byte size.png
The byte size of the middle is different.
Just FYI, Thanks
Could you please check if the issue happens again when you run the same comparison? If possible, please attach the files that cause the problem so we can try to reproduce it. Also, please let us know which version of WinMerge you are using.
Do you have a debug version of WinMerge (a version that logs the comparison-results-activity to the file-comparison-list/log) to show how WinMerge evaluates the comparison results of each file?
I attached the PNGs to my posts just to show you from the 'WinMerge Comparison Results' itself that WinMerge is displaying/reporting incorrect results. They are evidence that the file-comparison-list/log(Result) for some files is NOT being reported correctly (although there may be 1 or more bugs involved for different incorrect results).
I can email you the debug log when I see incorrect comparison results and you can research the log yourself. Please advise, Thanks FWIW 25-30 years ago I used a commercial Terminal Emulation Program and I had to use a debug version for the Developer to find an elusive bug. About 25 years ago I reported a "bug" in a database application. I was told that that bug had been there for 20 years and I was the first to discover/report it.
Now for example: I used WinMerge to evaluate file comparisons that reported 14 files with differences; selecting all and running refresh-selected found 4 files with differences, which means 10 were falsely reported as different.
I am NOT doing anything unusual other taking more care to verify/double-check the comparison results. These "bugs" may have been there all along and no one has discovered/reported them.
I am using WinMerge to add new and updated personal documents and removing deleted documents from the archive (I normally do NOT see incorrect reports in this because the difference in the date/size is obvious).
I also use WinMerge to periodically compare archive drives searching for weak or bad sectors. It is NOT common, but from time to time I do find files flagged as different when they have the same size and date. Bad sectors or a bad copy can be the cause of files having the same size and date and the contents still be different. When WinMerge shows a file with the same size and date and reporting that the contents is different, I verify that by running the DOS file compare cmd and more often than not 'fc' shows no difference.
It would be possible to build a debug version of WinMerge that logs detailed comparison activity, but since it’s difficult to fix an issue that we cannot reproduce on our side, we’d really like to reproduce the problem here first.
From your description, it sounds like the issue occurs occasionally rather than always — is that correct? Could you please tell us roughly how often it happens?
From your screenshots, it looks like you were comparing LibreOffice installer files. Could you please provide the list of those files? We’d like to try downloading them ourselves and see if we can reproduce the problem.
Also, could you please attach the text file displayed from Help → Configuration in WinMerge? Some personal information is automatically masked, but please review the file before uploading and remove any parts you don’t want to share.