WinMerge 2.16.12.0 Error message comparing zipped files in TortoiseSVN

[Andreas-Schniertshauer]

Hi,
I use WinMerge in TortoiseSVN to compare zipped files, when I select a .zip file in the Windows explorer and select "SVN Show Log" from the context menu of the .zip file I get a subversion history of all commits of this zip file, when I double click the very first file in history to show the difference I get an error message with red X from WinMerge: "Error Drive:Path\File.zip.svn017.tmp.zip The system cannot access the file". If I click OK WinMerge shows all files contained in the .zip in the WinMerge folder view and in the column "Comparison result" "Right only Drive:\path\File.ext" is shown. When I double click the interesting file I get the normal WinMerge comparion view (Untitled left (empty) and right file (initial content)), and the comparision result is exactly what I expect - it is the same result if I compare the first commit of a normal file (in WinMerge left is empty and on the right the new file content is show - all fine as expected).
My Question: is it possible to disable the error message in WinMerge, if not, can a "I don't want to show this message again" be implemented? I ask because the behavior should be the same as with the normal file and because "I know what I am doing" and I expect that left is empty and I don't want to see the message and click every time to close the dialog.
I thought it has something to do with the plugins, but I disabled all in the "Plugins Settings" dialog.
I disabled "Automatically verify paths in Open-dialog" in Options\General, but that did not help.

Remark: the two files file.zip.svn000.tmp.zip and file.zip.svn001.tmp.zip exist in the %Appdata%\Local\Temp folder but one file file.zip.svn001.tmp.zip has size 0.
Remark: subversion / TortoiseSVN is not causing the error: when I do a compare on the generated tmp.zip files I also get this message from WinMerge, so it seems that the message is shown because of the 0 sized file.
When I use WinMerge from the command line:
"c:\Program Files\WinMerge\WinMergeU.exe" File.zip.svn000.tmp.zip File.zip.svn001.tmp.zip
I also get the error message.
Remark: When I rename the file "C:\Program Files\WinMerge\Merge7z\7z.dll" to e.g. "C:\Program Files\WinMerge\Merge7z\7z.dll_" so that it is not used by WinMerge, the error message is not shown, is this file necessary, I ask, because when building the git trunk there is no such file, and the diff on zip files is working without it.
Thank you very much,
Andreas.

[sdottaka]

This error message seems to be displayed by the 7-Zip DLL (7z.dll) used by WinMerge, which unfortunately cannot be controlled from the WinMerge side.

[Andreas-Schniertshauer]

The WinMerge.iss installer shows that the 7z.dll is taken from Source: ....\Build\Merge7z\7z.dll; but when I build the Merge7z project from the ALL.vs2019.sln no 7z.dll appears in the folder and any other folder. How is it being build? The sources I found in Externals\sevenzip\

[Andreas-Schniertshauer]

The message box is opened in Format7zDLL::Interface::Open in file winmerge\ArchiveSupport\Merge7z\Merge7zCommon.cpp in the catch case Alert is called, so maybe it would be possible to supress it.