Long overdue micro clean-up.

* jc/finalize-temp-file:
  sha1_file.c: rename move_temp_to_file() to finalize_object_file()

"git clone $URL", when cloning from a site whose sole purpose is to
host a single repository (hence, no path after <scheme>://<site>/),
tried to use the site name as the new repository name, but did not
remove username or password when <site> part was of the form
<user>@<pass>:<host>.  The code is taught to redact these.

* ps/guess-repo-name-at-root:
  clone: abort if no dir name could be guessed
  clone: do not use port number as dir name
  clone: do not include authentication data in guessed dir

"git clone $URL" in recent releases of Git contains a regression in
the code that invents a new repository name incorrectly based on
the $URL.  This has been corrected.

* jk/guess-repo-name-regression-fix:
  clone: use computed length in guess_dir_name
  clone: add tests for output directory

A negative !ref entry in multi-value transfer.hideRefs
configuration can be used to say "don't hide this one".

* jk/negative-hiderefs:
  refs: support negative transfer.hideRefs
  docs/config.txt: reorder hideRefs config

Running tests with the "-x" option to make them verbose had some
unpleasant interactions with other features of the test suite.

* jk/test-with-x:
  test-lib: disable trace when test is not verbose
  test-lib: turn off "-x" tracing during chain-lint check

t1509 test that requires a dedicated VM environment had some
bitrot, which has been corrected.

* ps/t1509-chroot-test-fixup:
  tests: fix cleanup after tests in t1509-root-worktree
  tests: fix broken && chains in t1509-root-worktree

* sb/check-return-from-read-ref:
  transport-helper: die on errors reading refs.

"git pull" in recent releases of Git has a regression in the code
that allows custom path to the --upload-pack=<program>.  This has
been corrected.

Note that this is irrelevant for 'master' with "git pull" rewritten
in C.

* mm/pull-upload-pack:
  pull.sh: quote $upload_pack when passing it to git-fetch

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

Allow untracked cache (experimental) to be used when sparse
checkout (experimental) is also in use.

* dt/untracked-sparse:
  untracked-cache: support sparse checkout

* ta/docfix-index-format-tech:
  typofix for index-format.txt

An off-by-one error made "git remote" to mishandle a remote with a
single letter nickname.

* mh/get-remote-group-fix:
  get_remote_group(): use skip_prefix()
  get_remote_group(): eliminate superfluous call to strcspn()
  get_remote_group(): rename local variable "space" to "wordlen"
  get_remote_group(): handle remotes with single-character names

"git pull --rebase" has been taught to pay attention to
rebase.autostash configuration.

* kd/pull-rebase-autostash:
  pull: allow dirty tree when rebase.autostash enabled

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

* sb/remove-unused-var-from-builtin-add:
  add: remove dead code

* sb/parse-options-codeformat:
  parse-options: align curly braces for all options

The code to perform multi-tree merges has been taught to repopulate
the cache-tree upon a successful merge into the index, so that
subsequent "diff-index --cached" (hence "status") and "write-tree"
(hence "commit") will go faster.

The same logic in "git checkout" may now be removed, but that is a
separate issue.

* dt/unpack-trees-cache-tree-revalidate:
  unpack-trees: populate cache-tree on successful merge

Tests that assume how reflogs are represented on the filesystem too
much have been corrected.

* dt/reflog-tests:
  tests: remove some direct access to .git/logs
  t/t7509: remove unnecessary manipulation of reflog

The "new-worktree-mode" hack in "checkout" that was added in
nd/multiple-work-trees topic has been removed by updating the
implementation of new "worktree add".

* es/worktree-add-cleanup: (25 commits)
  Documentation/git-worktree: fix duplicated 'from'
  Documentation/config: mention "now" and "never" for 'expire' settings
  Documentation/git-worktree: fix broken 'linkgit' invocation
  checkout: drop intimate knowledge of newly created worktree
  worktree: populate via "git reset --hard" rather than "git checkout"
  worktree: avoid resolving HEAD unnecessarily
  worktree: make setup of new HEAD distinct from worktree population
  worktree: detect branch-name/detached and error conditions locally
  worktree: add_worktree: construct worktree-population command locally
  worktree: elucidate environment variables intended for child processes
  worktree: make branch creation distinct from worktree population
  worktree: add: suppress auto-vivication with --detach and no <branch>
  worktree: make --detach mutually exclusive with -b/-B
  worktree: introduce options container
  worktree: simplify new branch (-b/-B) option checking
  worktree: improve worktree setup message
  branch: publish die_if_checked_out()
  checkout: teach check_linked_checkout() about symbolic link HEAD
  checkout: check_linked_checkout: simplify symref parsing
  checkout: check_linked_checkout: improve "already checked out" aesthetic
  ...

Rewrite "am" in "C".

* pt/am-builtin: (46 commits)
  git-am: add am.threeWay config variable
  builtin-am: remove redirection to git-am.sh
  builtin-am: check for valid committer ident
  builtin-am: implement legacy -b/--binary option
  builtin-am: implement -i/--interactive
  builtin-am: support and auto-detect mercurial patches
  builtin-am: support and auto-detect StGit series files
  builtin-am: support and auto-detect StGit patches
  builtin-am: rerere support
  builtin-am: invoke post-applypatch hook
  builtin-am: invoke pre-applypatch hook
  builtin-am: invoke applypatch-msg hook
  builtin-am: support automatic notes copying
  builtin-am: invoke post-rewrite hook
  builtin-am: implement -S/--gpg-sign, commit.gpgsign
  builtin-am: implement --committer-date-is-author-date
  builtin-am: implement --ignore-date
  builtin-am: pass git-apply's options to git-apply
  builtin-am: implement --[no-]scissors
  builtin-am: support --keep-cr, am.keepcr
  ...

Remove remaining cruft from  "git checkout --to", which
transitioned to "git worktree add".

* es/worktree-add:
  config: rename "gc.pruneWorktreesExpire" to "gc.worktreePruneExpire"
  Documentation/git-worktree: wordsmith worktree-related manpages
  Documentation/config: fix stale "git prune --worktree" reference
  Documentation/git-worktree: fix incorrect reference to file "locked"
  Documentation/git-worktree: consistently use term "linked working tree"

Code and documentation clean-up to "git bisect".

* ad/bisect-cleanup:
  bisect: don't mix option parsing and non-trivial code
  bisect: simplify the addition of new bisect terms
  bisect: replace hardcoded "bad|good" by variables
  Documentation/bisect: revise overall content
  Documentation/bisect: move getting help section to the end
  bisect: correction of typo

Since 5a688fe4 ("core.sharedrepository = 0mode" should set, not
loosen, 2009-03-25), we kept reminding ourselves:

    NEEDSWORK: this should be renamed to finalize_temp_file() as
    "moving" is only a part of what it does, when no patch between
    master to pu changes the call sites of this function.

without doing anything about it.  Let's do so.

The purpose of this function was not to move but to finalize.  The
detail of the primarily implementation of finalizing was to link the
temporary file to its final name and then to unlink, which wasn't
even "moving".  The alternative implementation did "move" by calling
rename(2), which is a fun tangent.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Due to various components of the URI being stripped off it may
happen that we fail to guess a directory name. We currently error
out with a message that it is impossible to create the working
tree '' in such cases. Instead, error out early with a sensible
error message hinting that a directory name should be specified
manually on the command line.
Signed-off-by: NPatrick Steinhardt <ps@pks.im>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

If the URI contains a port number and the URI's path component is
empty we fail to guess a sensible directory name. E.g. cloning a
repository 'ssh://example.com:2222/' we guess a directory name
'2222' where we would want the hostname only, e.g. 'example.com'.

We need to take care to not drop trailing port-like numbers in
certain cases. E.g. when cloning a repository 'foo/bar:2222.git'
we want to guess the directory name '2222' instead of 'bar'.
Thus, we have to first check the stripped URI for path separators
and only strip port numbers if there are path separators present.
This heuristic breaks when cloning a repository 'bar:2222.git',
though.
Signed-off-by: NPatrick Steinhardt <ps@pks.im>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

If the URI contains authentication data and the URI's path
component is empty, we fail to guess a sensible directory name.
E.g. cloning a repository 'ssh://user:password@example.com/' we
guess a directory name 'password@example.com' where we would want
the hostname only, e.g. 'example.com'.

The naive way of just adding '@' as a path separator would break
cloning repositories like 'foo/bar@baz.git' (which would
currently become 'bar@baz' but would then become 'baz' only).
Instead fix this by first dropping the scheme and then greedily
scanning for an '@' sign until we find the first path separator.
Signed-off-by: NPatrick Steinhardt <ps@pks.im>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Commit 7e837c64 (clone: simplify string handling in
guess_dir_name(), 2015-07-09) changed clone to use
strip_suffix instead of hand-rolled pointer manipulation.
However, strip_suffix will strip from the end of a
NUL-terminated string, and we may have already stripped some
characters (like directory separators, or "/.git"). This
leads to commands like:

  git clone host:foo.git/

failing to strip the ".git".

We must instead convert our pointer arithmetic into a
computed length and feed that to strip_suffix_mem, which will
then reduce the length further for us.

It would be nicer if we could drop the pointer manipulation
entirely, and just continually strip using strip_suffix. But
that doesn't quite work for two reasons:

  1. The early suffixes we're stripping are not constant; we
     need to look for is_dir_sep, which could be one of
     several characters.

  2. Mid-way through the stripping we compute the pointer
     "start", which shows us the beginning of the pathname.
     Which really give us two lengths to work with: the
     offset from the start of the string, and from the start
     of the path. By using pointers for the early part, we
     can just compute the length from "start" when we need
     it.
Signed-off-by: NJeff King <peff@peff.net>
Acked-by: NSebastian Schuberth <sschuberth@gmail.com>
Signed-off-by: NPatrick Steinhardt <ps@pks.im>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

When we run "git clone $url", clone guesses from the $url
what to name the local output directory. We don't have any
test coverage of this, so let's add some basic tests.

This reveals a few problems:

  - cloning "foo.git/" does not properly remove the ".git";
    this is a recent regression from 7e837c64 (clone:
    simplify string handling in guess_dir_name(), 2015-07-09)

  - likewise, cloning foo/.git does not seem to handle the
    bare case (we should end up in foo.git, but we try to
    use foo/.git on the local end), which also comes from
    7e837c64.

  - cloning the root is not very smart about URL parsing,
    and usernames and port numbers may end up in the
    directory name

All of these tests are marked as failures.
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NPatrick Steinhardt <ps@pks.im>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

The "-x" test-script option turns on the shell's "-x"
tracing, which can help show why a particular test is
failing. Unfortunately, this can create false negatives in
some tests if they invoke a shell function with its stderr
redirected. t5512.10 is such a test, as it does:

    test_must_fail git ls-remote refs*master >actual 2>&1 &&
    test_cmp exp actual

The "actual" file gets the "-x" trace for the test_must_fail
function, which prevents it from matching the expected
output.

There's no way to avoid this without managing the
trace flag inside each sub-function, which isn't really a
workable solution. But unless you specifically care about
t5512.10, we can work around it by enabling tracing only for
the specific tests we want.

You can already do:

    ./t5512-ls-remote.sh -x --verbose-only=16

to see the trace only for a specific test. But that doesn't
_disable_ the tracing in the other tests; it just sends it
to /dev/null. However, there's no point in generating a
trace that the user won't see, so we can simply disable
tracing whenever it doesn't have a matching verbose flag.

The normal case of just "./t5512-ls-remote.sh -x" stays the
same, as "-x" already implies "--verbose" (and
"--verbose-only" overrides "--verbose", which is why this
works at all). And for our test, we need only check
$verbose, as maybe_setup_verbose will have already
set that flag based on the $verbose_only list).
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Now that GIT_TEST_CHAIN_LINT is on by default, running:

    ./t0000-basic.sh -x --verbose-only=1

starts with:

    expecting success:
            find .git/objects -type f -print >should-be-empty &&
            test_line_count = 0 should-be-empty

    + exit 117
    error: last command exited with $?=117
    + find .git/objects -type f -print
    + test_line_count = 0 should-be-empty
    + test 3 != 3
    + wc -l
    + test 0 = 0
    ok 1 - .git/objects should be empty after git init in an empty repo

This is confusing, as the "exit 117" line and the error line
(which is printed in red, no less!) are not part of the test
at all, but are rather in the separate chain-lint test_eval.
Let's unset the "trace" variable when eval-ing the chain
lint check, which avoids this.

Note that we cannot just do a one-shot variable like:

    trace= test_eval ...

as the behavior of one-shot variables for function calls
is not portable.
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

If you hide a hierarchy of refs using the transfer.hideRefs
config, there is no way to later override that config to
"unhide" it. This patch implements a "negative" hide which
causes matches to immediately be marked as unhidden, even if
another match would hide it. We take care to apply the
matches in reverse-order from how they are fed to us by the
config machinery, as that lets our usual "last one wins"
config precedence work (and entries in .git/config, for
example, will override /etc/gitconfig).

So you can now do:

  $ git config --system transfer.hideRefs refs/secret
  $ git config transfer.hideRefs '!refs/secret/not-so-secret'

to hide refs/secret in all repos, except for one public bit
in one specific repo. Or you can even do:

  $ git clone \
      -u "git -c transfer.hiderefs="!refs/foo" upload-pack" \
      remote:repo.git

to clone remote:repo.git, overriding any hiding it has
configured.

There are two alternatives that were considered and
rejected:

  1. A generic config mechanism for removing an item from a
     list. E.g.: (e.g., "[transfer] hideRefs -= refs/foo").

     This is nice because it could apply to other
     multi-valued config, as well. But it is not nearly as
     flexible. There is no way to say:

       [transfer]
       hideRefs = refs/secret
       hideRefs = refs/secret/not-so-secret

     Having explicit negative specifications means we can
     override previous entries, even if they are not the
     same literal string.

  2. Adding another variable to override some parts of
     hideRefs (e.g., "exposeRefs").

     This solves the problem from alternative (1), but it
     cannot easily obey the normal config precedence,
     because it would use two separate lists. For example:

       [transfer]
       hideRefs = refs/secret
       exposeRefs = refs/secret/not-so-secret
       hideRefs = refs/secret/not-so-secret/no-really-its-secret

     With two lists, we have to apply the "expose" rules
     first, and only then apply the "hide" rules. But that
     does not match what the above config intends.

     Of course we could internally parse that to a single
     list, respecting the ordering, which saves us having to
     invent the new "!" syntax. But using a single name
     communicates to the user that the ordering _is_
     important. And "!" is well-known for negation, and
     should not appear at the beginning of a ref (it is
     actually valid in a ref-name, but all entries here
     should be fully-qualified, starting with "refs/").
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

During cleanup we do a simple 'rm /*' to remove leftover files
from previous tests. As 'rm' errors out when there is anything it
cannot delete and there are directories present at '/' it will
throw an error, causing the '&&' chain to fail.

Fix this by explicitly removing the files.
Signed-off-by: NPatrick Steinhardt <ps@pks.im>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Signed-off-by: NPatrick Steinhardt <ps@pks.im>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Signed-off-by: NPatrick Steinhardt <ps@pks.im>
Acked-by: NEric Sunshine <sunshine@sunshineco.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Add the am.threeWay configuration variable to use the -3 or --3way
option of git am by default. When am.threeway is set and not desired
for a specific git am command, the --no-3way option can be used to
override it.
Signed-off-by: NRemi Lespinet <remi.lespinet@ensimag.grenoble-inp.fr>
Signed-off-by: NPaul Tan <pyokagan@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

At the beginning of the rewrite of git-am.sh to C, in order to not break
existing test scripts that depended on a functional git-am, a
redirection to git-am.sh was introduced that would activate if the
environment variable _GIT_USE_BUILTIN_AM was not defined.

Now that all of git-am.sh's functionality has been re-implemented in
builtin/am.c, remove this redirection, and retire git-am.sh into
contrib/examples/.
Signed-off-by: NPaul Tan <pyokagan@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

When commit_tree() is called, if the user does not have an explicit
committer ident configured, it will attempt to construct a default
committer ident based on the user's and system's info (e.g. gecos field,
hostname etc.) However, if a default committer ident is unable to be
constructed, commit_tree() will die(), but at this point of git-am's
execution, there will already be changes made to the index and work
tree.

This can be confusing to new users, and as such since d64e6b04 (Keep
Porcelainish from failing by broken ident after making changes.,
2006-02-18) git-am.sh will check to see if the committer ident has been
configured, or a default one can be constructed, before even starting to
apply patches.

Re-implement this in builtin/am.c.
Signed-off-by: NPaul Tan <pyokagan@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

The -b/--binary option was initially implemented in 087b6742 (git-am:
--binary; document --resume and --binary., 2005-11-16). The option will
pass the --binary flag to git-apply to allow it to apply binary patches.

However, in 2b6eef94 (Make apply --binary a no-op., 2006-09-06), --binary
was been made a no-op in git-apply. Following that, since cb3a160d
(git-am: ignore --binary option, 2008-08-09), the --binary option in
git-am is ignored as well.

In 6c15a1c6 (am: officially deprecate -b/--binary option, 2012-03-13),
the --binary option was tweaked to its present behavior: when set, the
message:

	The -b/--binary option has been a no-op for long time, and it
	will be removed. Please do not use it anymore.

will be printed.

Re-implement this in builtin/am.c.
Signed-off-by: NPaul Tan <pyokagan@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Since d1c5f2a4 (Add git-am, applymbox replacement., 2005-10-07),
git-am.sh supported the --interactive mode. After parsing the patch mail
and extracting the patch, commit message and authorship info, an
interactive session will begin that allows the user to choose between:

* applying the patch

* applying the patch and all subsequent patches (by disabling
  interactive mode in subsequent patches)

* skipping the patch

* editing the commit message

Since f89ad67f (Add [v]iew patch in git-am interactive., 2005-10-25),
git-am.sh --interactive also supported viewing the patch to be applied.

When --resolved-ing in --interactive mode, we need to take care to
update the patch with the contents of the index, such that the correct
patch will be displayed when the patch is viewed in interactive mode.

Re-implement the above in builtin/am.c
Signed-off-by: NPaul Tan <pyokagan@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Since 0cfd1120 (am: preliminary support for hg patches, 2011-08-29),
git-am.sh could convert mercurial patches to an RFC2822 mail patch
suitable for parsing with git-mailinfo, and queue them in the state
directory for application.

Since 15ced753 (git-am foreign patch support: autodetect some patch
formats, 2009-05-27), git-am.sh was able to auto-detect mercurial
patches by checking if the file begins with the line:

	# HG changeset patch

Re-implement the above in builtin/am.c.
Helped-by: NStefan Beller <sbeller@google.com>
Signed-off-by: NPaul Tan <pyokagan@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>