It used to be useful before I wrote "show-files", so that
show-diff would also tell what the cached files were. Now
it's just annoying.

patches.

In particular, it verifies that all the listed files are up-to-date
in the cache (or don't exist and are ready to be added).

You want things like this to check in a patch..

The kernel may not want it, but others probably do.

Noted (again) by Junio Hamano.

change. Promise.

It now always outputs all the revisions as <sha1>:<reachability>, where the
reachability is the bitmask of how that revision was reachable from the
commits in the argument list.

Trivially, if there is only one commit, the reachability will always be
(1 << 0) == 1 for all reachable revisions, and there won't be any edges
(so the "--edges" flag only makes sense with multiple commit keys).

or more commit points.

This is important both to know what the difference between two commit
points is, but also to figure out where to try to merge from.

Slight change of output format: it now lists all parents on the same line.

This allows it to work on initial commits too (which have no parents), and
also makes the output format a lot more intuitive.

I started out calling the tool "dircache". That's clearly moronic.

Problem noted by Randy Dunlap.

tree graph.

It's quite fast when the commit-objects are cached, but since
it has to walk every single commit-object, it also allows you
to cache an old state and just add on top of that.

It got broken when I changed it to use stdarg.

The size field isn't in the tree information, so we need to
update it if the sha1 matches.

After all, if you want to not allow others to read your
stuff, set your "umask" appropriately or make sure the
parent directories aren't readable/executable.

Let's bite the v3 bullet when it comes, although if people want to,
they can just state "or later at discretion of Linus" in their copyright
messages.

refresh the "stat" information.

We need this after having done a "read-tree", for example, when the
stat information does not match the checked-out tree, and we want to
start getting efficient cache matching against the parts of the tree
that are already up-to-date.

No, this doesn't make them easy to use, but makes diff-tree use
the "-r" flag for "recursive" (not "-R") and makes commit-tree
use AUTHOR_xxx environment flags (not COMMITTER_xxx) to match what
it actually does.

properly clear the reference count at init time. It happened to work
for me by pure luck.

Until it broke, and my unreferenced commit suddenly looked referenced
again. Fixed.

Which made fsck very quiet about objects it hadn't found. So add
it. 

We'll need to make things like these optional, because it's
perfectly ok to have partial history if you don't want it,
and don't want to go backwards. But for development, it's best
to always complain about missing sha1 object files that are
referenced from somewhere else.

This shows that I've lost track of one commit already. Most likely
because I forgot to update the .dircache/HEAD file when doing a
commit, so that the next commit referenced not the top-of-tree, but
the one older commit.

Having dangling commits is fine (in fact, you should always have
at least _one_ dangling commit in the top-of-tree). But it's
good to know about them.

Also make the return value of "cache_name_pos()" be sane: positive
or zero if we found it (it's the index into the cache array), and
"-pos-1" to indicate where it should go if we didn't.

And, perhaps more importantly, fix the fact that if a filename changed from a
directory to a file (or vice versa), we must consider it a delete and an add,
not a "filechange".

During original development I had different name-bases for source and
destination, so that I could make the output show how it got removed 
from "tree a" and added to "tree b", but we don't want that. We only
do recursive diffs on anything where the bases are exactly the same,
so we might as well just work with a single base.

Also, make the output for "changed" be a single line, since people
hated the separate '<' / '>' format. They were right. It sucked.

as it diffs them.

This makes diff-tree usable again in the new world order.

It now requires the "--add" flag before you add any new files, and
a "--remove" file if you want to mark files for removal. And giving
it the "--refresh" flag makes it just update all the files that it
already knows about.

It's got some debugging printouts etc still in it, but testing on the
kernel seems to show that it does indeed fix the issue with huge tree
files for each commit.

pathnames in them. We're migrating away from that.

This will cause tons of warnings for the current "sparse" archive,
but hell, better now than later.

This is totally untested, since we can't actually _write_ things that
way yet, but I'll get to that next, I hope. That should fix the
huge wasted space for kernel-sized tree objects.

Once I do the reference tracking, I'll also make it print out all the
HEAD commits it finds, which is even more interesting.

Very useful for creating diffs efficiently, and in general to see what has
changed in the namespace.

The "diff-tree" program needs it.

It will no longer update the actual working directory, just the
cache. To update the working directory, you need to use "checkout-cache".

This is needed for the change to make "read-tree" just read into the
cache (and then you do a "checkout-cache" to update your current dir
contents).

It's supposed to test the returned file type, not think that read_sha1_file()
tests it. Confusion from "cat-file" command line usage.

Make the warnings have newlines, and don't stop "checkout-cache -a"
just because a file already exists.

I'll also eventually change "read-tree" to only update the cache
information, instead of doing a checkout of the tree. Much nicer.

Like the cache filename finder, it's a generically useful function,
rather than something specific to the current "show-diff" thing.

It finds the cache entry position for a given name, and is
generally useful. Sure, everybody can just scan the active
cache array, but since it's sorted, you actually want to
search it with a binary search, so let's not duplicate that
logic all over the place.

Patches from Dave Jones and Ingo Molnar, but since I don't have any
infrastructure in place to use the old patch applicator scripts I
am trying to build up, I ended up fixing the thing by hand instead.

Credit where credit is due, though. Nice to see that people are
taking a look at the project even in this early stage.

internal format.

This doesn't yet check the reachability information, but we're getting
there.. Slowly.

Not all Linux distributions seem to need it (notably not YDL on ppc64), but
enough ones obviously do.