Re: [RFC] Submodules in GIT

On Thursday 2006 November 30 16:05, sf wrote:

Let's imagine a supermodule repository, and guess at it in more detail (I'll abbreviate some of the less interesting output):

$ git-cat-file -p HEAD tree fb02e78085ecf2f29045603df858b5362e5bf8a4 parent 4f2dba685507e4a8e07dac298c4024feaec6bd7d author Andy Parkins committer Andy Parkins $ git-cat-file -p fb02e78085ecf2f29045603df858b5362e5bf8a4 100644 blob 46bd4e284a57e2faa539e7b72d62a38867075af5 Makefile 040000 tree 49ea01373a986a3db44d66702714aa75059ffa2c doc 040000 subm d0a877464dc0198667a3e27ed3af8448ddacf947 libxcb

The "subm" type is our new ODB object that's going to store whatever we will need to access the submodule. "libxcb" has already told us where this submodule is in the supermodule tree.

$ git-cat-file -p d0a877464dc0198667a3e27ed3af8448ddacf947 submodulecommithash ccddf1d4b0cf7fd3a699d8b33cf5bc4c5c4435b7 submoduleurlhint git://anongit.freedesktop.org/git/xcb/libxcb

Here "submodulecommithash" is telling us what commit in the submodule is stored in this supermodule tree. The "submoduleurlhint" is to help when git-clone is used to clone this supermodule.

They key thing I wanted to point out here is the line:
  submodulecommithash ccddf1d4b0cf7fd3a699d8b33cf5bc4c5c4435b7
This is the ONLY link you have to the submodule.  I think this line represents 
the fundamental difference between our thinking on submodules.

I say:
 submodulecommithash points at a commit /in the submodule/
You say:
 "This commit is local to your repository".  i.e. it points at a commit in
 the supermodule, which in turn implies that the local commit object points
 at a local tree and local parents.

My question is therefore: tell me what that local commit's tree and parent's are? At the moment I am having difficulty understanding what meaningful things you could have in those fields.

Andy