Code clean-up.

* rs/blame-code-cleanup:
  blame: move blame_entry duplication to add_blame_entry()

Picking two versions of Git and running tests to make sure the
older one and the newer one interoperate happily has now become
possible.

* jk/interop-test:
  t/interop: add test of old clients against modern git-daemon
  t: add an interoperability test harness

The experimental "split index" feature has gained a few
configuration variables to make it easier to use.

* cc/split-index-config: (22 commits)
  Documentation/git-update-index: explain splitIndex.*
  Documentation/config: add splitIndex.sharedIndexExpire
  read-cache: use freshen_shared_index() in read_index_from()
  read-cache: refactor read_index_from()
  t1700: test shared index file expiration
  read-cache: unlink old sharedindex files
  config: add git_config_get_expiry() from gc.c
  read-cache: touch shared index files when used
  sha1_file: make check_and_freshen_file() non static
  Documentation/config: add splitIndex.maxPercentChange
  t1700: add tests for splitIndex.maxPercentChange
  read-cache: regenerate shared index if necessary
  config: add git_config_get_max_percent_split_change()
  Documentation/git-update-index: talk about core.splitIndex config var
  Documentation/config: add information for core.splitIndex
  t1700: add tests for core.splitIndex
  update-index: warn in case of split-index incoherency
  read-cache: add and then use tweak_split_index()
  split-index: add {add,remove}_split_index() functions
  config: add git_config_get_split_index()
  ...

* maint:
  Preparing for 2.12.1

Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Git v2.12 was shipped with an embarrassing breakage where various
operations that verify paths given from the user stopped dying when
seeing an issue, and instead later triggering segfault.
... and then to down to 'maint'.

* js/realpath-pathdup-fix:
  real_pathdup(): fix callsites that wanted it to die on error
  t1501: demonstrate NULL pointer access with invalid GIT_WORK_TREE

Code clean-up and a string truncation fix.

* mm/two-more-xstrfmt:
  bisect_next_all: convert xsnprintf to xstrfmt
  stop_progress_msg: convert xsnprintf to xstrfmt

The command-line parsing of "git log -L" copied internal data
structures using incorrect size on ILP32 systems.

* vn/line-log-memcpy-size-fix:
  line-log: use COPY_ARRAY to fix mis-sized memcpy

The code to parse "git log -L..." command line was buggy when there
are many ranges specified with -L; overrun of the allocated buffer
has been fixed.

* ax/line-log-range-merge-fix:
  line-log.c: prevent crash during union of too many ranges

The patch subcommand of "git add -i" was meant to have paths
selection prompt just like other subcommand, unlike "git add -p"
directly jumps to hunk selection.  Recently, this was broken and
"add -i" lost the paths selection dialog, but it now has been
fixed.

* jk/add-i-patch-do-prompt:
  add--interactive: fix missing file prompt for patch mode with "-i"

When a redirected http transport gets an error during the
redirected request, we ignored the error we got from the server,
and ended up giving a not-so-useful error message.

* jt/http-base-url-update-upon-redirect:
  http: attempt updating base URL only if no error

Add 32-bit Linux variant to the set of platforms to be tested with
Travis CI.

* js/travis-32bit-linux:
  Travis: also test on 32-bit Linux

Windows port wants to use OpenSSL's implementation of SHA-1
routines, so let them.

* jh/mingw-openssl-sha1:
  mingw: use OpenSSL's SHA-1 routines

Reduce authentication round-trip over HTTP when the server supports
just a single authentication method.

* jk/http-auth:
  http: add an "auto" mode for http.emptyauth
  http: restrict auth methods to what the server advertises

Signed-off-by: NJunio C Hamano <gitster@pobox.com>

"git branch --list" takes the "--abbrev" and "--no-abbrev" options
to control the output of the object name in its "-v"(erbose)
output, but a recent update started ignoring them; this fixes it
before the breakage reaches to any released version.

* kn/ref-filter-branch-list:
  branch: honor --abbrev/--no-abbrev in --list mode

"git push" had a handful of codepaths that could lead to a deadlock
when unexpected error happened, which has been fixed.

* jk/push-deadlock-regression-fix:
  send-pack: report signal death of pack-objects
  send-pack: read "unpack" status even on pack-objects failure
  send-pack: improve unpack-status error messages
  send-pack: use skip_prefix for parsing unpack status
  send-pack: extract parsing of "unpack" response
  receive-pack: fix deadlock when we cannot create tmpdir

Add 32-bit Linux variant to the set of platforms to be tested with
Travis CI.

* js/travis-32bit-linux:
  Travis: also test on 32-bit Linux

Recent versions of Git treats http alternates (used in dumb http
transport) just like HTTP redirects and requires the client to
enable following it, due to security concerns.  But we forgot to
give a warning when we decide not to honor the alternates.

* ew/http-alternates-as-redirects-warning:
  http: release strbuf on disabled alternates
  http: inform about alternates-as-redirects behavior

"git filter-branch --prune-empty" drops a single-parent commit that
becomes a no-op, but did not drop a root commit whose tree is empty.

* dp/filter-branch-prune-empty:
  p7000: add test for filter-branch with --prune-empty
  filter-branch: fix --prune-empty on parentless commits
  t7003: ensure --prune-empty removes entire branch when applicable
  t7003: ensure --prune-empty can prune root commit

The t/perf performance test suite was not prepared to test not so
old versions of Git, but now it covers versions of Git that are not
so ancient.

* jt/perf-updates:
  t/perf: add fallback for pre-bin-wrappers versions of git
  t/perf: use $MODERN_GIT for all repo-copying steps
  t/perf: export variable used in other blocks

"git fetch" that requests a commit by object name, when the other
side does not allow such an request, failed without much
explanation.

* mm/fetch-show-error-message-on-unadvertised-object:
  fetch-pack: add specific error for fetching an unadvertised object
  fetch_refs_via_pack: call report_unmatched_refs
  fetch-pack: move code to report unmatched refs to a function

"git branch @" created refs/heads/@ as a branch, and in general the
code that handled @{-1} and @{upstream} was a bit too loose in
disambiguating.

* jk/interpret-branch-name:
  checkout: restrict @-expansions when finding branch
  strbuf_check_ref_format(): expand only local branches
  branch: restrict @-expansions when deleting
  t3204: test git-branch @-expansion corner cases
  interpret_branch_name: allow callers to restrict expansions
  strbuf_branchname: add docstring
  strbuf_branchname: drop return value
  interpret_branch_name: move docstring to header file
  interpret_branch_name(): handle auto-namelen for @{-1}

A few tests were run conditionally under (rare) conditions where
they cannot be run (like running cvs tests under 'root' account).

* ab/cond-skip-tests:
  gitweb tests: skip tests when we don't have Time::HiRes
  gitweb tests: change confusing "skip_all" phrasing
  cvs tests: skip tests that call "cvs commit" when running as root

Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Documentation for "git ls-files" did not refer to core.quotePath

* ah/doc-ls-files-quotepath:
  Documentation: improve description for core.quotePath

"git diff --quiet" relies on the size field in diff_filespec to be
correctly populated, but diff_populate_filespec() helper function
made an incorrect short-cut when asked only to populate the size
field for paths that need to go through convert_to_git() (e.g. CRLF
conversion).

* jc/diff-populate-filespec-size-only-fix:
  diff: do not short-cut CHECK_SIZE_ONLY check in diff_populate_filespec()

The command-line parsing of "git log -L" copied internal data
structures using incorrect size on ILP32 systems.

* vn/line-log-memcpy-size-fix:
  line-log: use COPY_ARRAY to fix mis-sized memcpy

Code clean-up.

* jk/ewah-use-right-type-in-sizeof:
  ewah: fix eword_t/uint64_t confusion

The code to parse "git log -L..." command line was buggy when there
are many ranges specified with -L; overrun of the allocated buffer
has been fixed.

* ax/line-log-range-merge-fix:
  line-log.c: prevent crash during union of too many ranges

There is no need for Python only to give a few messages to the
standard error stream, but we somehow did.

* ss/remote-bzr-hg-placeholder-wo-python:
  contrib: git-remote-{bzr,hg} placeholders don't need Python

Git v2.12 was shipped with an embarrassing breakage where various
operations that verify paths given from the user stopped dying when
seeing an issue, and instead later triggering segfault.

* js/realpath-pathdup-fix:
  real_pathdup(): fix callsites that wanted it to die on error
  t1501: demonstrate NULL pointer access with invalid GIT_WORK_TREE

The patch subcommand of "git add -i" was meant to have paths
selection prompt just like other subcommand, unlike "git add -p"
directly jumps to hunk selection.  Recently, this was broken and
"add -i" lost the paths selection dialog, but it now has been
fixed.

* jk/add-i-patch-do-prompt:
  add--interactive: fix missing file prompt for patch mode with "-i"

Windows port wants to use OpenSSL's implementation of SHA-1
routines, so let them.

* jh/mingw-openssl-sha1:
  mingw: use OpenSSL's SHA-1 routines

All callers of add_blame_entry() allocate and copy the second argument.
Let the function do it for them, reducing code duplication.
Signed-off-by: NRene Scharfe <l.s.r@web.de>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

This test just checks that old clients can clone and fetch
from a newer git-daemon. The opposite should also be true,
but it's hard to test ancient versions of git-daemon because
they lack basic options like "--listen".

Note that we have to make a slight tweak to the
lib-git-daemon helper from the regular tests, so that it
starts the daemon with our correct git.a version.
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

The current test suite is good at letting you test a
particular version of Git. But it's not very good at letting
you test _two_ versions and seeing how they interact (e.g.,
one cloning from the other).

This commit adds a test harness that will build two
arbitrary versions of git and make it easy to call them from
inside your tests. See the README and the example script for
details.
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Code clean-up.

* rs/log-email-subject:
  pretty: use fmt_output_email_subject()
  log-tree: factor out fmt_output_email_subject()

"git stash save" takes a pathspec so that the local changes can be
stashed away only partially.

* tg/stash-push:
  stash: allow pathspecs in the no verb form
  stash: use stash_push for no verb form
  stash: teach 'push' (and 'create_stash') to honor pathspec
  stash: refactor stash_create
  stash: add test for the create command line arguments
  stash: introduce push verb