Leak fixes.

* ma/reduce-heads-leakfix:
  reduce_heads: fix memory leaks
  builtin/merge-base: free commit lists

Leak fixes.

* ma/bisect-leakfix:
  bisect: fix memory leak when returning best element
  bisect: fix off-by-one error in `best_bisection_sorted()`
  bisect: fix memory leak in `find_bisection()`
  bisect: change calling-convention of `find_bisection()`

A fix for an ancient bug in "git apply --ignore-space-change" codepath.

* rs/apply-fuzzy-match-fix:
  apply: avoid out-of-bounds access in fuzzy_matchlines()

Doc update around use of "format-patch --subject-prefix" etc.

* ad/submitting-patches-title-decoration:
  doc/SubmittingPatches: correct subject guidance

Error checking in "git imap-send" for empty response has been
improved.

* rs/imap-send-next-arg-fix:
  imap-send: handle missing response codes gracefully
  imap-send: handle NULL return of next_arg()

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

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

Code cleanup.

* rs/sequencer-rewrite-file-cleanup:
  sequencer.c: check return value of close() in rewrite_file()
  sequencer: use O_TRUNC to truncate files
  sequencer: factor out rewrite_file()

A test update.

* cb/t4201-robustify:
  t4201: make use of abbreviation in the test more robust

Replace the mailing address of FSF to a URL, as FSF prefers.

* tz/fsf-address-update:
  Replace Free Software Foundation address in license notices
  Replace Free Software Foundation address in license notices

Typofix.

* ad/rebase-i-serie-typofix:
  rebase -i: fix comment typo

We used to add an empty alternate object database to the system
that does not help anything; it has been corrected.

* jk/info-alternates-fix:
  link_alt_odb_entries: make empty input a noop

Building with NO_LIBPCRE1_JIT did not disable it, which has been fixed.

* ab/pcre-v2:
  grep: fix NO_LIBPCRE1_JIT to fully disable JIT

Some error messages did not quote filenames shown in it, which have
been fixed.

* sr/wrapper-quote-filenames:
  wrapper.c: consistently quote filenames in error messages

"git rebase -i" recently started misbehaving when a submodule that
is configured with 'submodule.<name>.ignore' is dirty; this has
been corrected.

* bw/rebase-i-ignored-submodule-fix:
  wt-status: actually ignore submodules when requested

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

* ks/mailmap:
  mailmap: use Kaartic Sivaraam's new address

Typofix.

* jm/relnotes-2.15-typofix:
  fix typos in 2.15.0 release notes

Doc update.

* cn/diff-indent-no-longer-is-experimental:
  diff: --indent-heuristic is no longer experimental

MinGW updates.

* js/mingw-redirect-std-handles:
  mingw: document the standard handle redirection
  mingw: optionally redirect stderr/stdout via the same handle
  mingw: add experimental feature to redirect standard handles

MinGW updates.

* js/wincred-empty-cred:
  wincred: handle empty username/password correctly
  t0302: check helper can handle empty credentials

MinGW updates.

* js/mingw-full-version-in-resources:
  mingw: include the full version information in the resources

The credential helper for libsecret (in contrib/) has been improved
to allow possibly prompting the end user to unlock secrets that are
currently locked (otherwise the secrets may not be loaded).

* dk/libsecret-unlock-to-load-fix:
  credential-libsecret: unlock locked secrets

Correct start-up sequence so that a repository could be placed
immediately under the root directory again (which was broken at
around Git 2.13).

* js/early-config:
  setup: avoid double slashes when looking for HEAD

UNC paths are also relevant in Cygwin builds and they are now
tested just like Mingw builds.

* ad/5580-unc-tests-on-cygwin:
  t5580: add Cygwin support

After an error from lstat(), diff_populate_filespec() function
sometimes still went ahead and used invalid data in struct stat,
which has been fixed.

* ao/diff-populate-filespec-lstat-errorpath-fix:
  diff: fix lstat() error handling in diff_populate_filespec()

Description of blame.{showroot,blankboundary,showemail,date}
configuration variables have been added to "git config --help".

* sb/blame-config-doc:
  config: document blame configuration

Command line completion (in contrib/) update.

* tb/complete-checkout:
  completion: add remaining flags to checkout

"git check-ref-format --branch @{-1}" bit a "BUG()" when run
outside a repository for obvious reasons; clarify the documentation
and make sure we do not even try to expand the at-mark magic in
such a case, but still call the validation logic for branch names.

* jc/check-ref-format-oor:
  check-ref-format doc: --branch validates and expands <branch>
  check-ref-format --branch: strip refs/heads/ using skip_prefix
  check-ref-format --branch: do not expand @{...} outside repository

A (possibly flakey) test fix.

* jc/t5601-copy-workaround:
  t5601: rm the target file of cp that could still be executing

A recent regression in "git rebase -i" that broke execution of git
commands from subdirectories via "exec" insn has been fixed.

* jk/rebase-i-exec-gitdir-fix:
  sequencer: pass absolute GIT_DIR to exec commands

A broken access to object databases in recent update to "git grep
--recurse-submodules" has been fixed.

* bw/grep-recurse-submodules:
  grep: take the read-lock when adding a submodule

"git status --ignored -u" did not stop at a working tree of a
separate project that is embedded in an ignored directory and
listed files in that other project, instead of just showing the
directory itself as ignored.

* js/submodule-in-excluded:
  status: do not get confused by submodules in excluded directories

"git commit", after making a commit, did not check for errors when
asking on what branch it made the commit, which has been correted.

* ao/check-resolve-ref-unsafe-result:
  commit: check result of resolve_ref_unsafe

Some codepaths did not check for errors when asking what branch the
HEAD points at, which have been fixed.

* jk/misc-resolve-ref-unsafe-fixes:
  worktree: handle broken symrefs in find_shared_symref()
  log: handle broken HEAD in decoration check
  remote: handle broken symrefs
  test-ref-store: avoid passing NULL to printf

Instead of using custom line comparison and hashing functions to
implement "moved lines" coloring in the diff output, use the pair
of these functions from lower-layer xdiff/ code.

* sb/diff-color-moved-use-xdl-recmatch:
  diff.c: get rid of duplicate implementation
  xdiff-interface: export comparing and hashing strings

The experimental "color moved lines differently in diff output"
feature was buggy around "ignore whitespace changes" edges, whihch
has been corrected.

* jk/diff-color-moved-fix:
  diff: handle NULs in get_string_hash()
  diff: fix whitespace-skipping with --color-moved
  t4015: test the output of "diff --color-moved -b"
  t4015: check "negative" case for "-w --color-moved"
  t4015: refactor --color-moved whitespace test

"auto" as a value for the columnar output configuration ought to
judge "is the output consumed by humans?" with the same criteria as
"auto" for coloured output configuration, i.e. either the standard
output stream is going to tty, or a pager is in use.  We forgot the
latter, which has been fixed.

* kd/auto-col-with-pager-fix:
  column: do not include pager.c
  column: show auto columns when pager is active

TravisCI build updates.

* sg/travis-fixes:
  travis-ci: don't build Git for the static analysis job
  travis-ci: fix running P4 and Git LFS tests in Linux build jobs

If an empty string is passed to link_alt_odb_entries(), our
loop finds no entries and we link nothing. But we still do
some preparatory work to normalize the object directory
path, even though we'll never look at the result. This
triggers in basically every git process, since we feed the
usually-empty ALTERNATE_DB_ENVIRONMENT to the function.

Let's detect early that there's nothing to do and return.
While we're at it, let's treat NULL the same as an empty
string as a favor to our callers. That saves
prepare_alt_odb() from having to cover this case.
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>