When checkout dwim is added in [1], it is restricted to only dwim when
certain conditions are met and fall back to default checkout behavior
otherwise. It turns out falling back could be confusing. One of the
conditions to turn

    git checkout frotz

to

    git checkout -b frotz origin/frotz

is that frotz must not exist as a file. But when the user comes to
expect "git checkout frotz" to create the branch "frotz" and there
happens to be a file named "frotz", git's silently reverting "frotz"
file content is not helping. This is reported in Git mailing list [2]
and even used as an example of "Git is bad" elsewhere [3].

We normally try to do the right thing, but when there are multiple
"right things" to do, it's best to leave it to the user to decide.
Check this case, ask the user to to disambiguate:

- "git checkout -- foo" will check out path "foo"
- "git checkout foo --" will dwim and create branch "foo" [4]

For users who do not want dwim, use --no-guess. It's useless in this
particular case because "git checkout --no-guess foo --" will just
fail. But it could be used by scripts.

[1] 70c9ac2f (DWIM "git checkout frotz" to "git checkout -b frotz
    origin/frotz" - 2009-10-18)
[2] https://public-inbox.org/git/CACsJy8B2TVr1g+k+eSQ=pBEO3WN4_LtgLo9gpur8X7Z9GOFL_A@mail.gmail.com/
[3] https://news.ycombinator.com/item?id=18230655
[4] a047fafc (checkout: allow dwim for branch creation for "git
    checkout $branch --" - 2013-10-18)
Signed-off-by: NNguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

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

The support for format-patch (and send-email) by the command-line
completion script (in contrib/) has been simplified a bit.

* nd/complete-format-patch:
  completion: use __gitcomp_builtin for format-patch

Pathspec matching against a tree object were buggy when negative
pathspec elements were involved, which has been fixed.

* nd/tree-walk-path-exclusion:
  tree-walk.c: fix overoptimistic inclusion in :(exclude) matching

The procedure to install dependencies before testing at Travis CI
is getting revamped for both simplicity and flexibility, taking
advantage of the recent move to the vm-based environment.

* sg/travis-install-dependencies:
  travis-ci: install packages in 'ci/install-dependencies.sh'

"git add" needs to internally run "diff-files" equivalent, and the
codepath learned the same optimization as "diff-files" has to run
lstat(2) in parallel to find which paths have been updated in the
working tree.

* bp/add-diff-files-optim:
  add: speed up cmd_add() by utilizing read_cache_preload()

The interface into "xdiff" library used to discover the offset and
size of a generated patch hunk by first formatting it into the
textual hunk header "@@ -n,m +k,l @@" and then parsing the numbers
out.  A new interface has been introduced to allow callers a more
direct access to them.

* jk/xdiff-interface:
  xdiff-interface: drop parse_hunk_header()
  range-diff: use a hunk callback
  diff: convert --check to use a hunk callback
  combine-diff: use an xdiff hunk callback
  diff: use hunk callback for word-diff
  diff: discard hunk headers for patch-ids earlier
  diff: avoid generating unused hunk header lines
  xdiff-interface: provide a separate consume callback for hunks
  xdiff: provide a separate emit callback for hunks

Assorted fixes for bugs found while auditing -Wunused-parameter
warnings.

* jk/misc-unused-fixes:
  approxidate: fix NULL dereference in date_time()
  pathspec: handle non-terminated strings with :(attr)
  approxidate: handle pending number for "specials"
  rev-list: handle flags for --indexed-objects

The code to traverse objects for reachability, used to decide what
objects are unreferenced and expendable, have been taught to also
consider per-worktree refs of other worktrees as starting points to
prevent data loss.

* nd/per-worktree-ref-iteration:
  git-worktree.txt: correct linkgit command name
  reflog expire: cover reflog from all worktrees
  fsck: check HEAD and reflog from other worktrees
  fsck: move fsck_head_link() to get_default_heads() to avoid some globals
  revision.c: better error reporting on ref from different worktrees
  revision.c: correct a parameter name
  refs: new ref types to make per-worktree refs visible to all worktrees
  Add a place for (not) sharing stuff between worktrees
  refs.c: indent with tabs, not spaces

The helper function to refresh the cached stat information in the
in-core index has learned to perform the lstat() part of the
operation in parallel on multi-core platforms.

* bp/refresh-index-using-preload:
  refresh_index: remove unnecessary calls to preload_index()
  speed up refresh_index() by utilizing preload_index()

Code clean-up for a topic already in 'master'.

* ag/rebase-i-in-c:
  sequencer.c: remove a stray semicolon

"git send-email --transfer-encoding=..." in recent versions of Git
sometimes produced an empty "Content-Transfer-Encoding:" header,
which has been corrected.

* al/send-email-auto-cte-fixup:
  send-email: avoid empty transfer encoding header

The history traversal used to implement the tag-following has been
optimized by introducing a new helper.

* ds/add-missing-tags:
  remote: make add_missing_tags() linear
  test-reach: test get_reachable_subset
  commit-reach: implement get_reachable_subset

Windows fix.

* sh/mingw-safer-compat-poll:
  poll: use GetTickCount64() to avoid wrap-around issues

In preparation to the day when we can deprecate and remove the
"rebase -p", make sure we can skip and later remove tests for
it.

* js/rebase-p-tests:
  tests: optionally skip `git rebase -p` tests
  t3418: decouple test cases from a previous `rebase -p` test case
  t3404: decouple some test cases from outcomes of previous test cases

Unify code to read the author-script used in "git am" and the
commands that use the sequencer machinery, e.g. "git rebase -i".

* pw/am-rebase-read-author-script:
  sequencer: use read_author_script()
  add read_author_script() to libgit
  am: rename read_author_script()
  am: improve author-script error reporting
  am: don't die in read_author_script()

Replace three string-list instances used as look-up tables in "git
fetch" with hashmaps.

* jc/war-on-string-list:
  fetch: replace string-list used as a look-up table with a hashmap

"git rev-parse --exclude=* --branches --branches"  (i.e. first
saying "add only things that do not match '*' out of all branches"
and then adding all branches, without any exclusion this time")
worked as expected, but "--exclude=* --all --all" did not work the
same way, which has been fixed.

* ag/rev-parse-all-exclude-fix:
  rev-parse: clear --exclude list after 'git rev-parse --all'

"git fetch" was a bit loose in parsing resposes from the other side
when talking over the protocol v2.

* jt/tighten-fetch-proto-v2-response:
  fetch-pack: be more precise in parsing v2 response

The submodule support has been updated to read from the blob at
HEAD:.gitmodules when the .gitmodules file is missing from the
working tree.

* ao/submodule-wo-gitmodules-checked-out:
  t/helper: add test-submodule-nested-repo-config
  submodule: support reading .gitmodules when it's not in the working tree
  submodule: add a helper to check if it is safe to write to .gitmodules
  t7506: clean up .gitmodules properly before setting up new scenario
  submodule: use the 'submodule--helper config' command
  submodule--helper: add a new 'config' subcommand
  t7411: be nicer to future tests and really clean things up
  t7411: merge tests 5 and 6
  submodule: factor out a config_set_in_gitmodules_file_gently function
  submodule: add a print_config_from_gitmodules() helper

Code readability fix.

* nb/worktree-api-doc:
  worktree: rename is_worktree_locked to worktree_lock_reason
  worktree: update documentation for lock_reason and lock_reason_valid

Code readability fix.

* ma/sequencer-do-reset-saner-loop-termination:
  sequencer: break out of loop explicitly

Windows fix.

* js/mingw-utf8-env:
  mingw: reencode environment variables on the fly (UTF-16 <-> UTF-8)
  t7800: fix quoting

Windows fix.

* js/mingw-perl5lib:
  mingw: unset PERL5LIB by default
  config: move Windows-specific config settings into compat/mingw.c
  config: allow for platform-specific core.* config settings
  config: rename `dummy` parameter to `cb` in git_default_config()

Windows fix.

* js/mingw-isatty-and-dup2:
  mingw: fix isatty() after dup2()

A couple of tests used to leave the repository in a state that is
deliberately corrupt, which have been corrected.

* ab/pack-tests-cleanup:
  index-pack tests: don't leave test repo dirty at end
  pack-objects tests: don't leave test .git corrupt at end
  pack-objects test: modernize style

Tests for the recently introduced multi-pack index machinery.

* ds/test-multi-pack-index:
  packfile: close multi-pack-index in close_all_packs
  multi-pack-index: define GIT_TEST_MULTI_PACK_INDEX
  midx: close multi-pack-index on repack
  midx: fix broken free() in close_midx()

A pattern with '**' that does not have a slash on either side used
to be an invalid one, but the code now treats such double-asterisks
the same way as two normal asterisks that happen to be adjacent to
each other.

* nd/wildmatch-double-asterisk:
  wildmatch: change behavior of "foo**bar" in WM_PATHNAME mode

A fourth class of configuration files (in addition to the
traditional "system wide", "per user in the $HOME directory" and
"per repository in the $GIT_DIR/config") has been introduced so
that different worktrees that share the same repository (hence the
same $GIT_DIR/config file) can use different customization.

* nd/per-worktree-config:
  worktree: add per-worktree config files
  t1300: extract and use test_cmp_config()

Additional comment on a tricky piece of code to help developers.

* jk/stream-pack-non-delta-clarification:
  read_istream_pack_non_delta(): document input handling

"git ls-remote $there foo" was broken by recent update for the
protocol v2 and stopped showing refs that match 'foo' that are not
refs/{heads,tags}/foo, which has been fixed.

* jk/proto-v2-ref-prefix-fix:
  ls-remote: pass heads/tags prefixes to transport
  ls-remote: do not send ref prefixes for patterns

A regression in Git 2.12 era made "git fsck" fall into an infinite
loop while processing truncated loose objects.

* jk/detect-truncated-zlib-input:
  cat-file: handle streaming failures consistently
  check_stream_sha1(): handle input underflow
  t1450: check large blob in trailing-garbage test

Split the overly large Documentation/config.txt file into million
little pieces.  This potentially allows each individual piece
included into the manual page of the command it affects more easily.

* nd/config-split: (81 commits)
  config.txt: remove config/dummy.txt
  config.txt: move worktree.* to a separate file
  config.txt: move web.* to a separate file
  config.txt: move versionsort.* to a separate file
  config.txt: move user.* to a separate file
  config.txt: move url.* to a separate file
  config.txt: move uploadpack.* to a separate file
  config.txt: move uploadarchive.* to a separate file
  config.txt: move transfer.* to a separate file
  config.txt: move tag.* to a separate file
  config.txt: move submodule.* to a separate file
  config.txt: move stash.* to a separate file
  config.txt: move status.* to a separate file
  config.txt: move splitIndex.* to a separate file
  config.txt: move showBranch.* to a separate file
  config.txt: move sequencer.* to a separate file
  config.txt: move sendemail-config.txt to config/
  config.txt: move reset.* to a separate file
  config.txt: move rerere.* to a separate file
  config.txt: move repack.* to a separate file
  ...

When we see a time like "noon", we pass "12" to our date_time() helper,
which sets the hour to 12pm. If the current time is before noon, then we
wrap around to yesterday using date_yesterday(). But unlike the normal
calls to date_yesterday() from approxidate_alpha(), we pass a NULL "num"
parameter. Since c27cc94f (approxidate: handle pending number for
"specials", 2018-11-02), that causes a segfault.

One way to fix this is by checking for NULL. But arguably date_time() is
abusing our helper by passing NULL in the first place (and this is the
only case where one of these "special" parsers is used this way). So
instead, let's have it just do the 1-day subtraction itself. It's still
just a one-liner due to our update_tm() helper.

Note that the test added here is a little funny, as we say "10am noon",
which makes the "10am" seem pointless.  But this bug can only be
triggered when it the currently-parsed hour is before the special time.
The latest special time is "tea" at 1700, but t0006 uses a hard-coded
TEST_DATE_NOW of 1900. We could reset TEST_DATE_NOW, but that may lead
to confusion in other tests. Just saying "10am noon" makes this test
self-contained.
Reported-by: NCarlo Arenas <carenas@gmail.com>
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>

Our test scripts can now take the '-V' option as a synonym for the
'--verbose-log' option.

* sg/test-verbose-log:
  test-lib: introduce the '-V' short option for '--verbose-log'

Code cleanup.

* rj/header-cleanup:
  commit-reach.h: add missing declarations (hdr-check)
  ewok_rlw.h: add missing 'inline' to function definition
  fetch-object.h: add missing declaration (hdr-check)

The "container" mode of TravisCI is going away.  Our .travis.yml
file is getting prepared for the transition.

* ss/travis-ci-force-vm-mode:
  travis-ci: no longer use containers

* sg/test-rebase-editor-fix:
  t3404-rebase-interactive: test abbreviated commands

Build portability fix.

* tb/char-may-be-unsigned:
  path.c: char is not (always) signed