Re: git-reflog 70 minutes at 100% cpu and counting

On Thu, 2009-12-17 at 00:38 -0500, Nicolas Pitre wrote:

Moving the reflog data aside (i.e. mv .git/logs .git/logs.bak) it seems 
that d936ff8 is not referenced anymore.

I found the other one as follows:

First I tried

$ git rev-list --all --objects

This resulted in:

[...]
4f7911b0b0dbd187131a109cf00161a0c6a9d727 arch/x86
ea868257c1eabc31e0ea7941efa42b543978b3fa arch/x86/kvm
a0c11ead723956c667172a9f3fb6787684fe7ff5 arch/x86/kvm/paging_tmpl.h
b556b6aad8b1aacfecb1dd4a56dbd389674687b5 arch/x86/kvm/x86.c
68a9733ae3315d7e2bfec2037dfeee4db8a6f6a1 drivers
error: Could not read 29b6c2fb1390b4fd350a5ecc78f1156fc5d91e9f
fatal: bad tree object 29b6c2fb1390b4fd350a5ecc78f1156fc5d91e9f

Because of the way objects are enumerated, we can be pretty sure that 
the bad tree object is referenced by the tree object 68a9733a 
corresponding to drivers/.  Let's verify that:

$ git ls-tree 68a9733a
100644 blob 00cf9553f74065291612b0971337f79995933a06    Kconfig
100644 blob c1bf41737936ab00be4a87563a0bb0638074785d    Makefile
040000 tree d4e847de9bf2450842936582ea7cc6778413825b    accessibility
040000 tree 29b6c2fb1390b4fd350a5ecc78f1156fc5d91e9f    acpi

This alone almost certainly tells me how I broke it.

For quite some time (a period of months) linux-next was broken and I had
to carry a patch to ACPI to make it boot.  I dropped that patch at the
head of my stgit trees in all of my repositories.  So I wouldn't be at
all surprised to learn that eventually kernel-2 found that object in
kernel-1.  Sometime when I dropped that patch from kernel-1 (because it
finally got fixed upstream) I can see how it broke.

But now that patch shouldn't be needed by any tree since I have long
since dropped it from the stgit stack.  So if we cleaned up all of the
useless objects in this tree I bet this object wouldn't be needed.  Not
exactly a situation that I'd expect git to be able to dig out of itself
thought.

I'm creating clean repos and going to do no work in my -alt    :)

Thanks everyone!

-Eric