Re: corrupt object on git-gc

["Yossi Leybovich" <sleybo@gmail.com>]

On Nov 9, 2007 11:28 AM, Linus Torvalds <torvalds@linux-foundation.org> wrote:
> and you should now have a line that looks like
>
>        10064 blob 4b9458b3786228369c63936db65827de3cc06200     my-magic-file

That works and now I know the file
>
> The easiest way to do it is to do
>
>        git log --raw --all --full-history -- subdirectory/my-magic-file
>
> and that will show you the whole log for that file (please realize that
> the tree you had may not be the top-level tree, so you need to figure out
> which subdirectory it was in on your own), and because you're asking for
> raw output, you'll now get something like
>
>        commit abc
>        Author:
>        Date:
>          ..
>        :100644 100644 4b9458b... newsha... M  somedirectory/my-magic-file
>
>
>        commit xyz
>        Author:
>        Date:
>
>          ..
>        :100644 100644 oldsha... 4b9458b... M   somedirectory/my-magic-file
>
> and this actually tells you what the *previous* and *subsequent* versions
> of that file were! So now you can look at those ("oldsha" and "newsha"
> respectively), and hopefully you have done commits often, and can
> re-create the missing my-magic-file version by looking at those older and
> newer versions!
>
> If you can do that, you can now recreate the missing object with

Ok, tried that and unfortuantly the SHA1 number is apear only one

[mellanox@mellanox-compile ib]$ git log --raw --all --full-history --
SymmK/St.c  | grep 4b9
:100755 100755 308806c... 4b9458b3786228369c63936db65827de3cc06200 M
 SymmK/St.c

git log --raw --all --full-history -- SymmK/St.c

...
...
commit 597e70e7dc8e06a7cdbe4d9e9727411c964bd023
Author: sleybo <sleybo@mellanox.co.il>
Date:   Fri Oct 5 10:41:43 2007 -0400

    1. increase QPs parameters - QP is bigger than 4k
    2. lock buffers use the dma key
    3. add prints

:100755 100755 308806c... 4b9458b3786228369c63936db65827de3cc06200 M
 SymmK/St.c


What intersting is that the SHA1 that I looked for apear only once
(only as new SHA1)

So I checkout version of the file which produce the old SHA1 308806c....

[mellanox@mellanox-compile ib-tmp]$ git checkout mlx4-start -- SymmK/St.c
[mellanox@mellanox-compile ib-tmp]$  git hash-object -w SymmK/St.c
308806cf3a864656a49d00edc35b9505abd627a2

than I did
[mellanox@mellanox-compile ib-tmp]$ git diff-tree --stdin -p --pretty
597e70e7dc8e06a7cdbe4d9e9727411c964bd023  > commit-597e70e

( which is the commit SHA1)

[mellanox@mellanox-compile ib-tmp]$ git apply commit-597e70e
Adds trailing whitespace.
../ib/commit-597e70e:1622:
Adds trailing whitespace.
../ib/commit-597e70e:1646:                      (int)devif->lock_dma +
lockid*sizeof(u64),
warning: 2 lines add whitespace errors.
[mellanox@mellanox-compile ib-tmp]$  git hash-object -w SymmK/St.c
e69de29bb2d1d6434b8b29ae775ad8c2e48c5391


So the same commit actual lead to the wrong SHA1
(I tried this flow on different file and it works)

I think I am close but still not there , any suggestions ?

Thanks
Yossi