Re: [ANNOUNCE] chronoversion: chronological archiving script with temporary commits

Hi,

On Tue, 13 Mar 2007, Johannes Schindelin wrote:

Hi,

On Tue, 13 Mar 2007, Shawn O. Pearce wrote:

quoted

David Tweed [off-list ref] wrote:

quoted

A question for those who understand things: I stash the last written
_tree_'s hash in a tag and then when a new "commit's" directory tree
is written starts look to see if it's the same SHA value. If it is I
know I can avoid the commit. At the moment I'm using

   if os.path.exists(lastTreeFile) and
tree==open(lastTreeFile,"r").read()[:40]:

to be safe just in case a user, eg, goes mad and manually deletes that
record. Clearly this is going to hit trouble if git ever decides to
put this tag into a packed refs file.
Is there any neat way of using builtin stuff like git-rev-parse to ask
if a ref has a given SHA1 value and return an easily parsed yes/no
answer?

The common idiom if you want to compare trees to see if you
need to make a commit is:

	oldc=`git rev-parse $tagname^{commit}`
	oldt=`git rev-parse $oldc^{tree}`
	newt`git write-tree`

	new=`git write-tree`

D'OH!

	newt=`git write-tree`

Oh, well...