Documentation/git-rebase.txt: -f forces a rebase that would otherwise be a no-op

"Current branch is a descendant of the commit you are rebasing onto"
does not necessarily mean "rebase" requires "--force".  For a plain
vanilla "history flattening" rebase, the rebase can be done without
forcing if there is a merge between the tip of the branch being
rebased and the commit you are rebasing onto, even if the tip is
descendant of the other.

[jc: reworded both the text and the log description]

Signed-off-by: Sergey Organov <sorganov@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
make config --add behave correctly for empty and NULL values

Currently if we have a config file like,
[foo]
        baz
        bar =

and we try something like, "git config --add foo.baz roll", Git will
segfault. Moreover, for "git config --add foo.bar roll", it will
overwrite the original value instead of appending after the existing
empty value.

The problem lies with the regexp used for simulating --add in
`git_config_set_multivar_in_file()`, "^$", which in ideal case should
not match with any string but is true for empty strings. Instead use a
regexp like "a^" which can not be true for any string, empty or not.

For removing the segfault add a check for NULL values in `matches()` in
config.c.

Signed-off-by: Tanay Abhra <tanayabh@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
send-pack: take refspecs over stdin

Pushing a large number of refs works over most transports,
because we implement send-pack as an internal function.
However, it can sometimes fail when pushing over http,
because we have to spawn "git send-pack --stateless-rpc" to
do the heavy lifting, and we pass each refspec on the
command line. This can cause us to overflow the OS limits on
the size of the command line for a large push.

We can solve this by giving send-pack a --stdin option and
using it from remote-curl.  We already dealt with this on
the fetch-pack side in 078b895 (fetch-pack: new --stdin
option to read refs from stdin, 2012-04-02). The stdin
option (and in particular, its use of packet-lines for
stateless-rpc input) is modeled after that solution.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
t9300: test filedelete command

Add new fast-import test series for filedelete command.

Signed-off-by: Maxim Bublis <satori@yandex-team.ru>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
fast-import: fix segfault in store_tree()

Branch tree is NULLified by filedelete command if we are trying
to delete root tree. Add sanity check and use load_tree() in that case.

Signed-off-by: Maxim Bublis <satori@yandex-team.ru>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
index-pack: fix race condition with duplicate bases

When we are resolving deltas in an indexed pack, we do it by
first selecting a potential base (either one stored in full
in the pack, or one created by resolving another delta), and
then resolving any deltas that use that base.  When we
resolve a particular delta, we flip its "real_type" field
from OBJ_{REF,OFS}_DELTA to whatever the real type is.

We assume that traversing the objects this way will visit
each delta only once. This is correct for most packs; we
visit the delta only when we process its base, and each
object (and thus each base) appears only once. However, if a
base object appears multiple times in the pack, we will try
to resolve any deltas based on it once for each instance.

We can detect this case by noting that a delta we are about
to resolve has already had its real_type field flipped, and
we already do so with an assert().  However, if multiple
threads are in use, we may race with another thread on
comparing and flipping the field. We need to synchronize the
access.

The right mechanism for doing this is a compare-and-swap (we
atomically "claim" the delta for our own and find out
whether our claim was successful). We can implement this
in C by using a pthread mutex to protect the operation. This
is not the fastest way of doing a compare-and-swap; many
processors provide instructions for this, and gcc and other
compilers provide builtins to access them. However, some
experiments showed that lock contention does not cause a
significant slowdown here. Adding c-a-s support for many
compilers would increase the maintenance burden (and we
would still end up including the pthread version as a
fallback).

Note that we only need to touch the OBJ_REF_DELTA codepath
here. An OBJ_OFS_DELTA object points to its base using an
offset, and therefore has only one base, even if another
copy of that base object appears in the pack (we do still
touch it briefly because the setting of real_type is
factored out of resolve_data).

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
reachable.c: add HEAD to reachability starting commits

HEAD is not explicitly used as a starting commit for
calculating reachability, so if it's detached and reflogs
are disabled it may be pruned.

Add tests which demonstrate it. Test 'prune: prune former HEAD after checking
out branch' also reverts changes to repository.

Signed-off-by: Max Kirillov <max@max630.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
fsck: exit with non-zero status upon error from fsck_obj()

Upon finding a corrupt loose object, we forgot to note the error to
signal it with the exit status of the entire process.

[jc: adjusted t1450 and added another test]

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
config: avoid a funny sentinel value "a^"

Introduce CONFIG_REGEX_NONE as a more explicit sentinel value to say
"we do not want to replace any existing entry" and use it in the
implementation of "git config --add".

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
fsck: return non-zero status on missing ref tips

Fsck tries hard to detect missing objects, and will complain
(and exit non-zero) about any inter-object links that are
missing. However, it will not exit non-zero for any missing
ref tips, meaning that a severely broken repository may
still pass "git fsck && echo ok".

The problem is that we use for_each_ref to iterate over the
ref tips, which hides broken tips. It does at least print an
error from the refs.c code, but fsck does not ever see the
ref and cannot note the problem in its exit code. We can solve
this by using for_each_rawref and noting the error ourselves.

In addition to adding tests for this case, we add tests for
all types of missing-object links (all of which worked, but
which we were not testing).

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
mailinfo: make ">From" in-body header check more robust

Since commit 81c5cf7 (mailinfo: skip bogus UNIX From line inside
body, 2006-05-21), we have treated lines like ">From" in the body as
headers. This makes "git am" work for people who erroneously paste
the whole output from format-patch:

  From 12345abcd...fedcba543210 Mon Sep 17 00:00:00 2001
  From: them
  Subject: [PATCH] whatever

into their email body (assuming that an mbox writer then quotes
"From" as ">From", as otherwise we would actually mailsplit on the
in-body line).

However, this has false positives if somebody actually has a commit
body that starts with "From "; in this case we erroneously remove
the line entirely from the commit message. We can make this check
more robust by making sure the line actually looks like a real mbox
"From" line.

Inspect the line that begins with ">From " a more carefully to only
skip lines that match the expected pattern (note that the datestamp
part of the format-patch output is designed to be kept constant to
help those who write magic(5) entries).

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Documentation/git-rebase.txt: <upstream> must be given to specify <branch>

Current syntax description makes one wonder if there is any
syntactic way to distinguish between <branch> and <upstream> so that
one can specify <branch> but not <upstream>, but that is not the
case.

Make it explicit that these arguments are positional, i.e. the
earlier ones cannot be omitted if you want to give later ones.

Signed-off-by: Sergey Organov <sorganov@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
mailinfo: work around -Wstring-plus-int warning

The just-released Apple Xcode 6.0.1 has -Wstring-plus-int enabled by
default which complains about pointer arithmetic applied to a string
literal:

    builtin/mailinfo.c:303:24: warning:
        adding 'long' to a string does not append to the string
            return !memcmp(SAMPLE + (cp - line), cp, strlen(SAMPLE) ...
                           ~~~~~~~^~~~~~~~~~~~~

Signed-off-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Merge branch 'so/rebase-doc' into maint

* so/rebase-doc:
  Documentation/git-rebase.txt: <upstream> must be given to specify <branch>
  Documentation/git-rebase.txt: -f forces a rebase that would otherwise be a no-op
Merge branch 'jk/send-pack-many-refspecs' into maint

"git push" over HTTP transport had an artificial limit on number of
refs that can be pushed imposed by the command line length.

* jk/send-pack-many-refspecs:
  send-pack: take refspecs over stdin
Merge branch 'jk/index-pack-threading-races' into maint

When receiving an invalid pack stream that records the same object
twice, multiple threads got confused due to a race.

* jk/index-pack-threading-races:
  index-pack: fix race condition with duplicate bases
Merge branch 'mb/fast-import-delete-root' into maint

An attempt to remove the entire tree in the "git fast-import" input
stream caused it to misbehave.

* mb/fast-import-delete-root:
  fast-import: fix segfault in store_tree()
  t9300: test filedelete command
Merge branch 'mk/reachable-protect-detached-head' into maint

Reachability check (used in "git prune" and friends) did not add a
detached HEAD as a starting point to traverse objects still in use.

* mk/reachable-protect-detached-head:
  reachable.c: add HEAD to reachability starting commits
Merge branch 'ta/config-add-to-empty-or-true-fix' into maint

"git config --add section.var val" used to lose existing
section.var whose value was an empty string.

* ta/config-add-to-empty-or-true-fix:
  config: avoid a funny sentinel value "a^"
  make config --add behave correctly for empty and NULL values
Merge branch 'jk/fsck-exit-code-fix' into maint

"git fsck" failed to report that it found corrupt objects via its
exit status in some cases.

* jk/fsck-exit-code-fix:
  fsck: return non-zero status on missing ref tips
  fsck: exit with non-zero status upon error from fsck_obj()