How do you verify that 2 copies of a VB 6 executable came from the same code base?
- by Tim Visher
I have a program under version control that has gone through multiple releases. A situation came up today where someone had somehow managed to point to an old copy of the program and thus was encountering bugs that have since been fixed. I'd like to go back and just delete all the old copies of the program (keeping them around is a company policy that dates from before version control was common and should no longer be necessary) but I need a way of verifying that I can generate the exact same executable that is better than saying "The old one came out of this commit so this one should be the same."
My initial thought was to simply MD5 hash the executable, store the hash file in source control, and be done with it but I've come up against a problem which I can't even parse.
It seems that every time the executable is generated (method: Open Project. File Make X.exe) it hashes differently. I've noticed that Visual Basic messes with files every time the project is opened in seemingly random ways but I didn't think that would make it into the executable, nor do I have any evidence that that is indeed what's happening. To try to guard against that I tried generating the executable multiple times within the same IDE session and checking the hashes but they continued to be different every time.
So that's:
Generate Executable
Generate MD5 Checksum: md5sum X.exe > X.md5
Verify MD5 for current executable: md5sum -c X.md5
Generate New Executable
Verify MD5 for new executable: md5sum -c X.md5
Fail verification because computed checksum doesn't match.
I'm not understanding something about either MD5 or the way VB 6 is generating the executable but I'm also not married to the idea of using MD5. If there is a better way to verify that two executables are indeed the same then I'm all ears.
Thanks in advance for your help!
