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mercurialdiffmercurial-extension

Automatic conversion of specific binary files to text to compare (diff) in Mercurial


I have several -small- binary files added in my Mercurial repository. The files are the "source" files of one of my development tools (report / form / class definitions).

I made a program that dumps this binary files to a text file to allow easy diffs between them. Is there any way to tell Mercurial that certain file extensions need to run this conversion before running the diff program? Or I have to set my conversion program as the main diff tool and run the conversion -or not- and then run the real diff program?


Solution

  • I ended up with a small batch previous to the diff program:

    @echo off
    set f1=%1
    set f2=%2
    ::Temporary dir created by hg to copy the snapshot file
    set tdir=%~dp1
    ::Original repository dir
    set repo=%~dp2
    ::Filename extension
    set ext=%~x1
    ::The binary files comes in pairs: scx/sct \ vcx/vct ...
    set ex2=%ext:~0,-1%t
    
    ::Check if "dumpable" extension
    echo %ext% | grep -iE "(vcx|vct|scx|sct|pjx|pjt|frx|frt)" > nul && goto DumpFile
    goto diff
    
    :DumpFile
    set f1="%tdir%\_Dump1.prg"
    set f2="%tdir%\_Dump2.prg"
    ::Get the pair file from the repository
    hg cat %repo%\%~n1%ex2% -o "%~dpn1%ex2%" -R %repo%
    
    ::Do the dump, then the diff
    MyDumpProgram.exe %1 %f1%
    MyDumpProgram.exe %2 %f2%
    goto diff
    
    :diff
    ExamDiff.exe %f1% %f2%
    pause
    

    and then config the batch in %UserProfile%\.hgrc

    [extdiff]
    cmd.ediff = d:\Utiles\diff2.bat