Re: more git updates..

From: David Lang
Date: Tue Apr 12 2005 - 00:38:52 EST


I've been reading this and have another thought for you guys to keep in mind for this tool.

version control of system config files on linux systems.

it sounds like you could put the / fileystem under the control of git (after teaching it to not cross fileystem boundries so you can have another filesystem to work with) and version control your entire system. if this was done it would be nice to add a item type that would referance a file in a distro package to save space. it sounds like you could run a git checkin daily (as part of the updatedb run for example) at very little cost.

for that matter by comparing the git data between servers (or between a server and an archive) you could easily use it to detect tampering.

sounds very interesting, but I'm going to let things settle down a bit before I try to tackle this (but you guys who ar working on it shoudl feel free to add the couple options nessasary to implement this if you want ;-)

David Lang

On Sun, 10 Apr 2005, Christopher Li wrote:

Date: Sun, 10 Apr 2005 17:28:50 -0400
From: Christopher Li <lkml@xxxxxxxxxxx>
To: Linus Torvalds <torvalds@xxxxxxxx>
Cc: Paul Jackson <pj@xxxxxxxxxxxx>, junkio@xxxxxxx, rddunlap@xxxxxxxx,
ross@xxxxxxxxxxxxxxxxx, linux-kernel@xxxxxxxxxxxxxxx
Subject: Re: more git updates..

I see. It just need some basic set operation (+, -, and)
and some way to select a set:


sha5--->
/
/
sha1-->sha2-->sha3--
\ /
\ /
>sha4


list sha1 # all the file list in changeset sha1
# {sha1}
list sha1,sha1 # same as above
list sha1,sha2 # all the file list in between changeset sha1
# and changeset sha2
# {sha1, sha2} in example
list sha1,sha3 # {sha1, sha2, sha3, sha4}

list sha1,any # all the change set reachable from sha1.
{sha1, ... sha5, ...}

new sha1,sha2 # all the new file add between in sha1, sha2 (+)
changed sha1,sha2 # add the changed file between sha1, sha2 (>) (<)
deleted sha1,sha2 # add the deleted file between sha1, sha2 (-)

before time # all the file before time
after time # all the file after time


So in my example, the file I want to delete is :

{list hack1, base}+ {list hack2, base} ... {list hack6, base} \
- [list official_merge, base ]



On Sun, Apr 10, 2005 at 04:21:08PM -0700, Linus Torvalds wrote:


the official tree. It is more for my local version control.

I have a plan. Namely to have a "list-needed" command, which you give one
commit, and a flag implying how much "history" you want (*), and then it
spits out all the sha1 files it needs for that history.

Then you delete all the other ones from your SHA1 archive (easy enough to
do efficiently by just sorting the two lists: the list of "needed" files
and the list of "available" files).

Script that, and call the command "prune-tree" or something like that, and
you're all done.

(*) The amount of history you want might be "none", which is to say that
you don't want to go back in time, so you want _just_ the list of tree and
blob objects associated with that commit.

That will be {list head}


Or you might want a "linear" history, which would be the longest path
through the parent changesets to the root.

That will be {list head,root}


Or you might want "all", which would follow all parents and all trees.

That will be {list any, root}


Or you might want to prune the history tree by date - "give me all
history, but cut it off when you hit a parent that was done more than 6
months ago".

That is {after -6month }


This "list-needed" thing is not just for pruning history either. If you
have a local tree "x", and you want to figure out how much of it you need
to send to somebody else who has an older tree "y", then what you'd do is
basically "list-needed x" and remove the set of "list-needed y". That
gives you the answer to the question "what's the minimum set of sha1 files
I need to send to the other guy so that he can re-create my top-of-tree".


That is {list x, any} - {list y, any}


My second plan is to make somebody else so fired up about the problem that
I can just sit back and take patches. That's really what I'm best at.
Sitting here, in the (rain) on the patio, drinking a foofy tropical drink,
and pressing the "apply" button. Then I take all the credit for my
incredible work.

Sounds like a good plan.

Chris

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