simplify-merges: drop merge from irrelevant side branch

The merge simplification rule stated in 6546b59 (revision traversal:
show full history with merge simplification, 2008-07-31) still
treated merge commits too specially.  Namely, in a history with this
shape:

	---o---o---M
	          /
         x---x---x

where three 'x' were on a history completely unrelated to the main
history 'o' and do not touch any of the paths we are following, we
still said that after simplifying all of the parents of M, 'x'
(which is the leftmost 'x' that rightmost 'x simplifies down to) and
'o' (which would be the last commit on the main history that touches
the paths we are following) are independent from each other, and
both need to be kept.

That is incorrect; when the side branch 'x' never touches the paths,
it should be removed to allow M to simplify down to the last commit
on the main history that touches the paths.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
config.mak.in: remove unused definitions

When 5566771 (autoconf: Use autoconf to write installation
directories to config.mak.autogen, 2006-07-03) introduced support
for autoconf generated config.mak file, it added an "export" for a
few common makefile variables, in addition to definitions of srcdir
and VPATH.

The "export" logically does not belong there.  The make variables
like mandir, prefix, etc, should be exported to submakes for people
who use config.mak and people who use config.mak.autogen the same
way; if we want to get these exported, that should be in the main
Makefile.

We do use mandir and htmldir in Documentation/Makefile, so let's
add export for them in the main Makefile instead.

We may eventually want to support VPATH, and srcdir may turn out to
be useful for that purpose, but right now nobody uses it, so it is
useless to define them in this file.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
sequencer.c: rework search for start of footer to improve clarity

This code sequence is somewhat difficult to read.  Let's rewrite it and add
some comments to improve clarity.

Signed-off-by: Brandon Casey <drafnel@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
commit, cherry-pick -s: remove broken support for multiline rfc2822 fields

Starting with c1e01b0c (commit: More generous accepting of RFC-2822 footer
lines, 2009-10-28), "git commit -s" carefully parses the last paragraph of
each commit message to check if it consists only of RFC2822-style headers,
in which case the signoff will be added as a new line in the same list:

   Reported-by: Reporter <reporter@example.com>
   Signed-off-by: Author <author@example.com>
   Acked-by: Lieutenant <lt@example.com>

It even included support for accepting indented continuation lines for
multiline fields.  Unfortunately the multiline field support is broken
because it checks whether buf[k] (the first character of the *next* line)
instead of buf[i] is a whitespace character.  The result is that any footer
with a continuation line is not accepted, since the last continuation line
neither starts with an RFC2822 field name nor is followed by a continuation
line.

That this has remained broken for so long is good evidence that nobody
actually needed multiline fields.  Rip out the broken continuation support.

There should be no functional change.

[Thanks to Jonathan Nieder for the excellent commit message]

Signed-off-by: Brandon Casey <bcasey@nvidia.com>
Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
t/test-lib-functions.sh: allow to specify the tag name to test_commit

The <message> part of test_commit() may not be appropriate for a tag name.
So let's allow test_commit to accept a fourth argument to specify the tag
name.

Signed-off-by: Brandon Casey <bcasey@nvidia.com>
Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
t/t3511: add some tests of 'cherry-pick -s' functionality

Add some tests to ensure that 'cherry-pick -s' operates in the following
manner:

   * Inserts a blank line before appending a s-o-b to a commit message that
     does not contain a s-o-b footer

   * Does not mistake first line "subject: description" as a s-o-b footer

   * Does not mistake single word message body as conforming to rfc2822

   * Appends a s-o-b when last s-o-b in footer does not match committer
     s-o-b, even when committer's s-o-b exists elsewhere in footer.

   * Does not append a s-o-b when last s-o-b matches committer s-o-b

   * Correctly detects a non-conforming footer containing a mix of s-o-b
     like elements and s-o-b elements. (marked "expect failure")

Signed-off-by: Brandon Casey <bcasey@nvidia.com>
Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
sequencer.c: recognize "(cherry picked from ..." as part of s-o-b footer

When 'cherry-pick -s' is used to append a signed-off-by line to a cherry
picked commit, it does not currently detect the "(cherry picked from..."
that may have been appended by a previous 'cherry-pick -x' as part of the
s-o-b footer and it will insert a blank line before appending a new s-o-b.

Let's detect "(cherry picked from...)" as part of the footer so that we
will produce this:

   Signed-off-by: A U Thor <author@example.com>
   (cherry picked from da39a3ee5e6b4b0d3255bfef95601890afd80709)
   Signed-off-by: C O Mmitter <committer@example.com>

instead of this:

   Signed-off-by: A U Thor <author@example.com>
   (cherry picked from da39a3ee5e6b4b0d3255bfef95601890afd80709)

   Signed-off-by: C O Mmitter <committer@example.com>

[with improvements from Jonathan Nieder]

Signed-off-by: Brandon Casey <bcasey@nvidia.com>
Acked-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
sequencer.c: require a conforming footer to be preceded by a blank line

Currently, append_signoff() performs a search for the last line of the
commit buffer by searching back from the end until it hits a newline.  If
it reaches the beginning of the buffer without finding a newline, that
means either the commit message was empty, or there was only one line in it.
In this case, append_signoff will skip the call to has_conforming_footer
since it already knows that it is necessary to append a newline before
appending the sob.

Let's perform this function inside of has_conforming_footer where it
appropriately belongs and generalize it so that we require that the
footer paragraph be an actual distinct paragraph separated by a blank
line.

Signed-off-by: Brandon Casey <drafnel@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
sequencer.c: always separate "(cherry picked from" from commit body

Start treating the "(cherry picked from" line added by cherry-pick -x
the same way that the s-o-b lines are treated.  Namely, separate them
from the main commit message body with an empty line.

Introduce tests to test this functionality.

Signed-off-by: Brandon Casey <bcasey@nvidia.com>
Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
sequencer.c: teach append_signoff how to detect duplicate s-o-b

Teach append_signoff how to detect a duplicate s-o-b in the commit footer.
This is in preparation to unify the append_signoff implementations in
log-tree.c and sequencer.c.

Fixes test in t3511.

Signed-off-by: Brandon Casey <bcasey@nvidia.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
sequencer.c: teach append_signoff to avoid adding a duplicate newline

Teach append_signoff to detect whether a blank line exists at the position
that the signed-off-by line will be added, and refrain from adding an
additional one if one already exists.  Or, add an additional line if one
is needed to make sure the new footer is separated from the message body
by a blank line.

Signed-off-by: Brandon Casey <bcasey@nvidia.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
t4014: more tests about appending s-o-b lines

[bc: Squash the tests from Duy's original unify-appending-sob series.

     Fix test 90 "signoff: some random signoff-alike" and mark as failing.
     Correct behavior should insert a blank line after message body and
     signed-off-by.

     Add two additional tests:

       1. failure to detect non-conforming elements in the footer when last
          line matches committer's s-o-b.
       2. ensure various s-o-b -like elements in the footer are handled as
          conforming. e.g. "Change-id: IXXXX or Bug: 1234"
]

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Brandon Casey <bcasey@nvidia.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
format-patch: update append_signoff prototype

This is a preparation step for merging with append_signoff from
sequencer.c

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Brandon Casey <bcasey@nvidia.com>
Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Unify appending signoff in format-patch, commit and sequencer

There are two implementations of append_signoff in log-tree.c and
sequencer.c, which do more or less the same thing.  Unify on top of the
sequencer.c implementation.

Add a test in t4014 to demonstrate support for non-s-o-b elements in the
commit footer provided by sequence.c:append_sob.  Mark tests fixed as
appropriate.

[Commit message mostly stolen from Nguyễn Thái Ngọc Duy's original
 unification patch]

Signed-off-by: Brandon Casey <bcasey@nvidia.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Makefile: do not export mandir/htmldir/infodir

These are defined in the main Makefile to be funny values that are
optionally relative to an unspecified location that is determined at
runtime.  They are only suitable for hardcoding in the binary via
the -DGIT_{MAN,HTML,INFO}_PATH=<value> C preprocessor options, and
are not real paths, contrary to what any sane person, and more
importantly, the Makefile in the documentation directory, would
expect.

A longer term fix is to introduce runtime_{man,html,info}dir variables
to hold these funny values, and make {man,html,info}dir variables
to have real paths whose default values begin with $(prefix), but
as a first step, stop exporting them from the top-level Makefile

Signed-off-by: Junio C Hamano <gitster@pobox.com>
upload-pack: use get_sha1_hex to parse "shallow" lines

When we receive a line like "shallow <sha1>" from the
client, we feed the <sha1> part to get_sha1. This is a
mistake, as the argument on a shallow line is defined by
Documentation/technical/pack-protocol.txt to contain an
"obj-id".  This is never defined in the BNF, but it is clear
from the text and from the other uses that it is meant to be
a hex sha1, not an arbitrary identifier (and that is what
fetch-pack has always sent).

We should be using get_sha1_hex instead, which doesn't allow
the client to request arbitrary junk like "HEAD@{yesterday}".
Because this is just marking shallow objects, the client
couldn't actually do anything interesting (like fetching
objects from unreachable reflog entries), but we should keep
our parsing tight to be on the safe side.

Because get_sha1 is for the most part a superset of
get_sha1_hex, in theory the only behavior change should be
disallowing non-hex object references. However, there is
one interesting exception: get_sha1 will only parse
a 40-character hex sha1 if the string has exactly 40
characters, whereas get_sha1_hex will just eat the first 40
characters, leaving the rest. That means that current
versions of git-upload-pack will not accept a "shallow"
packet that has a trailing newline, even though the protocol
documentation is clear that newlines are allowed (even
encouraged) in non-binary parts of the protocol.

This never mattered in practice, though, because fetch-pack,
contrary to the protocol documentation, does not include a
newline in its shallow lines. JGit follows its lead (though
it correctly is strict on the parsing end about wanting a
hex object id).

We do not adjust fetch-pack to send newlines here, as it
would break communication with older versions of git (and
there is no actual benefit to doing so, except for
consistency with other parts of the protocol).

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
upload-pack: do not add duplicate objects to shallow list

When the client tells us it has a shallow object via
"shallow <sha1>", we make sure we have the object, mark it
with a flag, then add it to a dynamic array of shallow
objects. This means that a client can get us to allocate
arbitrary amounts of memory just by flooding us with shallow
lines (whether they have the objects or not). You can
demonstrate it easily with:

  yes '0035shallow e83c5163316f89bfbde7d9ab23ca2e25604af290' |
  git-upload-pack git.git

We already protect against duplicates in want lines by
checking if our flag is already set; let's do the same thing
here. Note that a client can still get us to allocate some
amount of memory by marking every object in the repo as
"shallow" (or "want"). But this at least bounds it with the
number of objects in the repository, which is not under the
control of an upload-pack client.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
upload-pack: remove packet debugging harness

If you set the GIT_DEBUG_SEND_PACK environment variable,
upload-pack will dump lines it receives in the receive_needs
phase to a descriptor. This debugging harness is a strict
subset of what GIT_TRACE_PACKET can do. Let's just drop it
in favor of that.

A few tests used GIT_DEBUG_SEND_PACK to confirm which
objects get sent; we have to adapt them to the new output
format.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
fetch-pack: fix out-of-bounds buffer offset in get_ack

When we read acks from the remote, we expect either:

  ACK <sha1>

or

  ACK <sha1> <multi-ack-flag>

We parse the "ACK <sha1>" bit from the line, and then start
looking for the flag strings at "line+45"; if we don't have
them, we assume it's of the first type.  But if we do have
the first type, then line+45 is not necessarily inside our
string at all!

It turns out that this works most of the time due to the way
we parse the packets. They should come in with a newline,
and packet_read puts an extra NUL into the buffer, so we end
up with:

  ACK <sha1>\n\0

with the newline at offset 44 and the NUL at offset 45. We
then strip the newline, putting a NUL at offset 44. So
when we look at "line+45", we are looking past the end of
our string; but it's OK, because we hit the terminator from
the original string.

This breaks down, however, if the other side does not
terminate their packets with a newline. In that case, our
packet is one character shorter, and we start looking
through uninitialized memory for the flag. No known
implementation sends such a packet, so it has never come up
in practice.

This patch tightens the check by looking for a short,
flagless ACK before trying to parse the flag.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
send-pack: prefer prefixcmp over memcmp in receive_status

This code predates prefixcmp, so it used memcmp along with
static sizes. Replacing these memcmps with prefixcmp makes
the code much more readable, and the lack of static sizes
will make refactoring it in future patches simpler.

Note that we used to be unnecessarily liberal in parsing the
"unpack" status line, and would accept "unpack ok\njunk". No
version of git has ever produced that, and it violates the
BNF in Documentation/technical/pack-protocol.txt. Let's take
this opportunity to tighten the check by converting the
prefix comparison into a strcmp.

While we're in the area, let's also fix a vague error
message that does not follow our usual conventions (it
writes directly to stderr and does not use the "error:"
prefix).

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>