Re: [RFC] git-add update with all-0 object

On Thu, 30 Nov 2006, Theodore Tso wrote:

By the way, after thinking about this for a while, part of the problem
is that the name "index" really sucks.  Which is perhaps why Linus is
now trying to stop us from actually using the term "index" in these
discussions.  :-)    If we called it a "staging area", as our Great
Leader has suggested, I think it would be a lot easier for novice
users to understand.    Consider what is in the git man page:

	The index is a simple binary file, which contains an efficient
	representation of a virtual directory content at some random
	time.  It does so by a simple array that associates a set of
	names, dates, permissions and content (aka "blob") objects
	together. The cache is always kept ordered by name, and names
	are unique (with a few very specific rules) at any point in
	time, but the cache has no long-term meaning, and can be
	partially updated at any time.....

	In particular, the index file can have the representation of
	an intermediate tree that has not yet been instantiated. So
	the index can be thought of as a write-back cache, which can
	contain dirty information that has not yet been written back
	to the backing store.

For a kernel programmer, this might not be understandable --- but for
your typical application programmer, this is enough to cause him or
her to conclude that git is simply not meant for use by mere mortals.

My position on this subject is that "index" is a good name, but that 
description is a terrible description, and "index" is a word that needs a 
good description in context. If we just said up front:

 Git's "index" is a staging area that you use to prepare commits. It maps 
 filenames to content. It allows git to remember changes you want to put 
 into the next commit while you do more work. For normal commits, it is 
 not necessary to use the index, but it is very helpful for complicated 
 commits, because it lets you focus on the part you're still working on 
 while git remembers the part you're done with.

I think people would get it. (If it were called the "cache" still, it 
would be hopeless, because "cache" implies false things; "index" doesn't 
imply anything initially.)

Of course, we'd still have to disabuse people of the notion that the index 
can store the information "there's nothing at this path yet, but I'm 
interested in it", because that's a piece of information people often know 
before a file is ready, and think git would be able to remember in a 
staging area.

	-Daniel