On Wednesday, July 3, 2024 at 3:40:54 PM UTC+2 [email protected] wrote:

Hi,

As noted in the TortoiseSVN group [1], TortoiseUDiff will quit with an 
error message "The pipe has been ended" if you try to pipe a diff to the 
program. The original post uses git but it can be reproduced with any 
source (for example piping from svn).

The root cause seems to be the changes by csware in r29665 on December 18th 
(2023):

[[[
TortoiseUDiff: Improve error reporting

Based on TortoiseGit rev. 0cadd137babbbd87ba834020b101d05d21b7e8e4.
]]]

The code (only relevant lines):
[[[
    BOOL bRet  = ReadFile(hFile, data, sizeof(data), &dwRead, nullptr);
    while ((dwRead > 0) && (bRet))
    {
... send data to Scintilla and check status ...
        bRet = ReadFile(hFile, data, sizeof(data), &dwRead, nullptr);
    }
    if (!bRet)
    {
        if (hFile || wantStdIn)
        {
            MessageBox(*this, 
static_cast<LPCWSTR>(CFormatMessageWrapper()), L"TortoiseUDiff", 
MB_ICONEXCLAMATION);
            return false;
        }
...
     }
]]]

What seems to happen is that ReadFile returns when there is no more data. 
This causes MessageBox to be called with GetLastError() being 
ERROR_BROKEN_PIPE.

I think the same would happen with TortoiseGitUDiff (see [2]).

I'm not sure I understand exactly what is supposed to happen, in particular 
the check for if (hFile || wantStdIn). wantStdIn is set if TortoiseUDiff is 
called with /b, but documentation says /b is optional and STDIN will be 
used by default.


I think 'wantStdIn' is used to show errors in case stdin is not available. 
Because in that case, hFile would be null and no error would be reported.
 


Maybe a check for GetLastError() == ERROR_BROKEN_PIPE? I can't figure out 
from the documentation for ReadFile [4] how to detect EOF for a pipe.


Yes, that's the correct solution. Because when piping, the pipe gets broken 
when the source process (e.g. git.exe when doing a 'git diff | 
tortoiseudiff.exe') ends.

I'll commit a fix soon.

Stefan

-- 
You received this message because you are subscribed to the Google Groups 
"TortoiseSVN-dev" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to [email protected].
To view this discussion on the web visit 
https://groups.google.com/d/msgid/tortoisesvn-dev/461ed213-083b-47d2-9a39-80695c2af5fbn%40googlegroups.com.

Reply via email to