This introduces --pretty=oneline to git-rev-tree and
git-rev-list commands to show only the first line of the commit
message, without frills. 
Signed-off-by: NJunio C Hamano <junkio@cox.net>

As requested by Junio (who suggested --single-parents-only, but this
could forget a no-parent root).

Also, adds a few missing options to the usage string.
Signed-off-by: NJohannes Schindelin <Johannes.Schindelin@gmx.de>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

The King Penguin says:

    Now, for extra bonus points, maybe you should make "git-rev-list" also
    understand the "rev..rev" format (which you can't do with just the
    get_sha1() interface, since it expands into more).

The faithful servant makes it so.
Signed-off-by: NJunio C Hamano <junkio@cox.net>

Support for completely OpenSSL-less builds. FSF considers distributing GPL
binaries with OpenSSL linked in as a legal problem so this is trouble
e.g. for Debian, or some people might not want to install OpenSSL
anyway. If you

	make NO_OPENSSL=1

you get completely OpenSSL-less build, disabling --merge-order and using
Mozilla's SHA1 implementation.

Ported from Cogito.
Signed-off-by: NPetr Baudis <pasky@ucw.cz>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

This corner-case was triggered by a kernel commit that was not in date
order, due to a misconfigured time zone that made the commit appear three
hours older than it was.

That caused git-rev-list to traverse the commit tree in a non-obvious
order, and made it parse several of the _parents_ of the misplaced commit
before it actually parsed the commit itself. That's fine, but it meant
that the grandparents of the commit didn't get marked uninteresting,
because they had been reached through an "interesting" branch.

The reason was that "mark_parents_uninteresting()" (which is supposed to
mark all existing parents as being uninteresting - duh) didn't actually
traverse more than one level down the parent chain.

NORMALLY this is fine, since with the date-based traversal order,
grandparents won't ever even have been looked at before their parents (so
traversing the chain down isn't needed, because the next time around when
we pick out the parent we'll mark _its_ parents uninteresting), but since
we'd gotten out of order, we'd already seen the parent and thus never got
around to mark the grandparents.

Anyway, the fix is simple. Just traverse parent chains recursively.
Normally the chain won't even exist (since the parent hasn't been parsed
yet), so this is not actually going to trigger except in this strange
corner-case.

Add a comment to the simple one-liner, since this was a bit subtle, and I
had to really think things through to understand how it could happen.
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

The *_usage strings should not start with "usage: ", since the
usage() function gives its own.
Signed-off-by: NJunio C Hamano <junkio@cox.net>

We'll mark all the trees at the edges (as deep as we had to go to
realize that we have all the commits needed) as uninteresting.
Otherwise we'll occasionally list a lot of objects that were actually
available at the edge in a commit that we just never ended up parsing
because we could determine early that we had all relevant commits.

NOTE! The object listing is still just a _heuristic_.  It's guaranteed
to list a superset of the actual new objects, but there might be the
occasional old object in the list, just because the commit that
referenced it was much further back in the history.

For example, let's say that a recent commit is a revert of part of the
tree to much older state: since we didn't walk _that_ far back in the
commit history tree to list the commits necessary, git-rev-tree will
never have marked the old objects uninteresting, and we'll end up
listing them as "new".

That's ok.

When we allow a tag object in place of a commit object, we only
dereferenced the given tag once, which causes a tag that points at a tag
that points at a commit to be rejected.  Instead, dereference tag
repeatedly until we get a non-tag.

This patch makes change to two functions:

 - commit.c::lookup_commit_reference() is used by merge-base,
   rev-tree and rev-parse to convert user supplied SHA1 to that of
   a commit.
 - rev-list uses its own get_commit_reference() to do the same.

Dereferencing tags this way helps both of these uses.
Signed-off-by: NJunio C Hamano <junkio@cox.net>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

We still want the "top-most" uninteresting object to exist, so that we
know that we have reached it.

This change ensures that git-rev-list --merge-order produces the same result
irrespective of what position the --merge-order argument appears in the argument
list.
Signed-off-by: NJon Seymour <jon.seymour@gmail.com>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

That's what we should have done in the first place, since it not only
avoids another unnecessary flag, it also protects the commits from
showing up as duplicates later when they show up as parents of another
commit (in the pop_most_recent_commit() path).

This will hopefully also fix --topo-sort.

This was my cherry-pickng merge bug.  But topo-order still shows strange
behaviour with multiple heads, so keep gitk using --merge-order for now.

This patch implements a small tidy up of rev-list.c to reduce
(but not eliminate) the amount of ugliness associated
with the merge_order flag.
Signed-off-by: NJon Seymour <jon.seymour@gmail.com>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

..and move the DUPCHECK to rev-list.c since both the merge-order and the
upcoming topo-sort get confused by dups.

Jon wants the commits in a different order for merge-order.

Same argument order, same return type.  This allows us to use a function
pointer to choose one over the other.

Not only is it unnecessary, it incorrectly allows extraneous characters
at the end of the argument.

Junio noticed the --merge-order thing, and Jon points out that if we fix
that one, we should fix --show-breaks too.

We didn't sort the refs by date, so if you had multiple refs, the end
result would not be properly sorted.

We'd rather get the revisions in a slow but timely manner than
have to wait for them.

More infrastructure to do efficient incremental packs.

And make git-rev-list just silently ignore non-commit refs if we're not
asking for all objects.

Mainly making a lot of local functions and variables be marked "static",
but there was a "zero as NULL" warning in there too.

Now you can give git-rev-list tags, trees and blobs, and it will do the
proper reachability for them all. Knock wood.

Of course, you need the "--objects" flag to do anything but plain
commits.

We want to be able to just say "give a difference between these
objects", rather than limiting it to commits only.  This isn't there
yet, but it sets things up to be a bit easier.

Also move the common implementation of parsing the --pretty argument
format into commit.c rather than having duplicates in diff-tree.c and
rev-list.c.

The name isn't unique, it's just the first name that object is reached
through, so it's really nothing more than a hint.

When you do

	git-rev-list --objects $(git-rev-parse HEAD^..HEAD)

it now lists not only the "commit difference" between the parent of HEAD
and HEAD itself (which is normally just the parent, but in the case of a
merge will be all the newly merged commits), but also all the new tree
and blob objects that weren't in the original.

NOTE! It doesn't walk all the way to the root, so it doesn't do a full
object search in the full old history.  Instead, it will only look as
far back in the history as it needs to resolve the commits.  Thus, if
the commit reverts a blob (or tree) back to a state much further back in
history, we may end up listing some blobs (or trees) as "new" even
though they exist further back.

Regardless, the list of objects will be a superset (usually exact) list
of objects needed to go from the beginning commit to ending commit.

As a particularly obvious special case,

	git-rev-list --objects HEAD

will end up listing every single object that is reachable from the HEAD
commit.

Side note: the objects are sorted by "recency", with commits first.

This patch fixes a problem reported by Paul Mackerras regarding the interaction
of the --merge-order and --max-age switches of git-rev-list.

This patch applies to the current Linus HEAD. A cleaner fix for the same problem
in my current HEAD will follow later.

With this change, --merge-order produces the same result as no --merge-order
on the linux-2.6 git repository, to wit:

$> git-rev-list --max-age=1116330140 bcfff0b471a60df350338bcd727fc9b8a6aa54b2 | wc -l
655
$> git-rev-list --merge-order --max-age=1116330140 bcfff0b471a60df350338bcd727fc9b8a6aa54b2 | wc -l
655
Signed-off-by: NJon Seymour <jon.seymour@gmail.com>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

If b is reachable from a, then:

	 git-rev-list a b

argument would print one of the commits twice.

This patch fixes that problem. A previous problem fixed it for the
--merge-order switch.
Signed-off-by: NJon Seymour <jon.seymour@gmail.com>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Strangely, this warning only shows up when not compiling with "-O2",
which is why I didn't see it originally.

This is useful for doing binary searching for problems.  You start with
a known good and known bad point, and you then test the "halfway" point
in between:

	git-rev-list --bisect bad ^good

and you test that.  If that one tests good, you now still have a known
bad case, but two known good points, and you can bisect again:

	git-rev-list --bisect bad ^good1 ^good2

and test that point.  If that point is bad, you now use that as your
known-bad starting point:

	git-rev-list --bisect newbad ^good1 ^good2

and basically at every iteration you shrink your list of commits by
half: you're binary searching for the point where the troubles started,
even though there isn't a nice linear ordering.

This patch tidies up the git-rev-list documentation and epoch.c, which
are in severe clash with the unwritten coding style now, and quite
unreadable.

It also fixes up compile failures with older compilers due to variable
declarations after code.

The patch mostly wraps lines before or on the 80th column, removes
plenty of superfluous empty lines and changes comments from // to /* */.
Signed-off-by: NPetr Baudis <pasky@ucw.cz>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This patch linearises the GIT commit history graph into merge order
which is defined by invariants specified in Documentation/git-rev-list.txt.

The linearisation produced by this patch is superior in an objective sense
to that produced by the existing git-rev-list implementation in that
the linearisation produced is guaranteed to have the minimum number of
discontinuities, where a discontinuity is defined as an adjacent pair of
commits in the output list which are not related in a direct child-parent
relationship.

With this patch a graph like this:

	a4 ---
	| \   \
	|  b4 |
	|/ |  |
	a3 |  |
	|  |  |
	a2 |  |
	|  |  c3
	|  |  |
	|  |  c2
	|  b3 |
	|  | /|
	|  b2 |
	|  |  c1
	|  | /
	|  b1
	a1 |
	|  |
	a0 |
	| /
	root

Sorts like this:

	= a4
	| c3
	| c2
	| c1
	^ b4
	| b3
	| b2
	| b1
	^ a3
	| a2
	| a1
	| a0
	= root

Instead of this:

	= a4
	| c3
	^ b4
	| a3
	^ c2
	^ b3
	^ a2
	^ b2
	^ c1
	^ a1
	^ b1
	^ a0
	= root

A test script, t/t6000-rev-list.sh, includes a test which demonstrates
that the linearisation produced by --merge-order has less discontinuities
than the linearisation produced by git-rev-list without the --merge-order
flag specified. To see this, do the following:

	cd t
	./t6000-rev-list.sh
	cd trash
	cat actual-default-order
	cat actual-merge-order

The existing behaviour of git-rev-list is preserved, by default. To obtain
the modified behaviour, specify --merge-order or --merge-order --show-breaks
on the command line.

This version of the patch has been tested on the git repository and also on the linux-2.6
repository and has reasonable performance on both - ~50-100% slower than the original algorithm.

This version of the patch has incorporated a functional equivalent of the Linus' output limiting
algorithm into the merge-order algorithm itself. This operates per the notes associated
with Linus' commit 337cb3fb.

This version has incorporated Linus' feedback regarding proposed changes to rev-list.c.
(see: [PATCH] Factor out filtering in rev-list.c)

This version has improved the way sort_first_epoch marks commits as uninteresting.

For more details about this change, refer to Documentation/git-rev-list.txt
and http://blackcubes.dyndns.org/epoch/.
Signed-off-by: NJon Seymour <jon.seymour@gmail.com>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

You can ask to print out "raw" format (full headers, full body),
"medium" format (author and date, full body) or "short" format
(author only, condensed body).

Use "git-rev-list --pretty=short HEAD | less -S" for an example.

This makes git-rev-list use the same command line syntax to mark the
commits as git-rev-tree does, and instead of just allowing a start and
end commit, it allows an arbitrary list of "interesting" and "uninteresting"
commits.

For example, imagine that you had three branches (a, b and c) that you
are interested in, but you don't want to see stuff that already exists
in another persons three releases (x, y and z). You can do

	git-rev-list a b c ^x ^y ^z

(order doesn't matter, btw - feel free to put the uninteresting ones
first or otherwise swithc them around), and it will show all the
commits that are reachable from a/b/c but not reachable from x/y/z.

The old syntax "git-rev-list start end" would not be written as
"git-rev-list start ^end", or "git-rev-list ^end start".

There's no limit to the number of heads you can specify (unlike
git-rev-tree, which can handle a maximum of 16 heads).

Ok, now I'm happier.

Functions that do many things are bad. We should basically
just parse the arguments in main(). We're not quite there
yet, but it's a step in the right direction.

That pretty-prints the resulting commit messages, so

	git-rev-list --pretty HEAD v2.6.12-rc5 | less -S

basically ends up being a log of the changes between -rc5
and current head.

It uses the pretty-printing helper function I just extracted
from diff-tree.c.

It makes rev-list show the list of parents, the same
way git-rev-tree does (but without the expense).