Merge branch 'dt/empty-submodule-in-merge'

An empty directory in a working tree that can simply be nuked used
to interfere while merging or cherry-picking a change to create a
submodule directory there, which has been fixed..

* dt/empty-submodule-in-merge:
submodules: allow empty working-tree dirs in merge/cherry-pick

Merge branch 'jk/rev-parse-symbolic-parents-fix'

"git rev-parse --symbolic" failed with a more recent notation like
"HEAD^-1" and "HEAD^!".

* jk/rev-parse-symbolic-parents-fix:
rev-parse: fix parent shorthands with --symbolic

index-pack: skip collision check when not in repository

You can run "git index-pack path/to/foo.pack" outside of a
repository to generate an index file, or just to verify the
contents. There's no point in doing a collision check, since
we obviously do not have any objects to collide with.

The current code will blindly look in .git/objects based on
the result of setup_git_env(). That effectively gives us the
right answer (since we won't find any objects), but it's a
waste of time, and it conflicts with our desire to
eventually get rid of the "fallback to .git" behavior of
setup_git_env().

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

normalize_path_copy(): fix pushing to //server/share/dir on Windows

normalize_path_copy() is not prepared to keep the double-slash of a
//server/share/dir kind of path, but treats it like a regular POSIX
style path and transforms it to /server/share/dir.

The bug manifests when 'git push //server/share/dir master' is run,
because tmp_objdir_add_as_alternate() uses the path in normalized
form when it registers the quarantine object database via
link_alt_odb_entries(). Needless to say that the directory cannot be
accessed using the wrongly normalized path.

Fix it by skipping all of the root part, not just a potential drive
prefix. offset_1st_component takes care of this, see the
implementation in compat/mingw.c::mingw_offset_1st_component().

Signed-off-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

shortlog: test and document --committer option

This puts the final touches on the feature added by
fbfda15fb8 (shortlog: group by committer information,
2016-10-11).

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

t: use nongit() function where applicable

Many tests want to run a command outside of any git repo;
with the nongit() function this is now a one-liner. It saves
a few lines, but more importantly, it's immediately obvious
what the code is trying to accomplish.

This doesn't convert every such case in the test suite; it
just covers those that want to do a one-off command. Other
cases, such as the ones in t4035, are part of a larger
scheme of outside-repo files, and it's less confusing for
them to stay consistent with the surrounding tests.

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

index-pack: complain when --stdin is used outside of a repo

The index-pack builtin is marked as RUN_SETUP_GENTLY,
because it's perfectly fine to index a pack in the
filesystem outside of any repository. However, --stdin mode
will write the result to the object database, which does not
make sense outside of a repository. Doing so creates a bogus
".git" directory with nothing in it except the newly-created
pack and its index.

Instead, let's flag this as an error and abort.

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

t5000: extract nongit function to test-lib-functions.sh

This function abstracts the idea of running a command
outside of any repository (which is slightly awkward to do
because even if you make a non-repo directory, git may keep
walking up outside of the trash directory). There are
several scripts that use the same technique, so let's make
the function available for everyone.

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

shortlog: group by committer information

In some situations you may want to group the commits not by author,
but by committer instead.

For example, when I just wanted to look up what I'm still missing from
linux-next in the current merge window, I don't care so much about who
wrote a patch, as what git tree it came from, which generally boils
down to "who committed it".

So make git shortlog take a "-c" or "--committer" option to switch
grouping to that.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

merge: mark usage error strings for translation

The nearby error messages are already marked for
translation, but these new ones aren't.

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

README: replace gmane link with public-inbox

The general status and future of gmane is unclear at this
point, but certainly it does not seem to be carrying
gmane.comp.version-control.git at all anymore. Let's point
to public-inbox.org, which seems to be the favored archive
on the list these days (and which uses message-ids in its
URLs, making the links somewhat future-proof).

Reported-by: Chiel ten Brinke <ctenbrinke@gmail.com>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

http: respect protocol.*.allow=user for http-alternates

The http-walker may fetch the http-alternates (or
alternates) file from a remote in order to find more
objects. This should count as a "not from the user" use of
the protocol. But because we implement the redirection
ourselves and feed the new URL to curl, it will use the
CURLOPT_PROTOCOLS rules, not the more restrictive
CURLOPT_REDIR_PROTOCOLS.

The ideal solution would be for each curl request we make to
know whether or not is directly from the user or part of an
alternates redirect, and then set CURLOPT_PROTOCOLS as
appropriate. However, that would require plumbing that
information through all of the various layers of the http
code.

Instead, let's check the protocol at the source: when we are
parsing the remote http-alternates file. The only downside
is that if there's any mismatch between what protocol we
think it is versus what curl thinks it is, it could violate
the policy.

To address this, we'll make the parsing err on the picky
side, and only allow protocols that it can parse
definitively. So for example, you can't elude the "http"
policy by asking for "HTTP://", even though curl might
handle it; we would reject it as unknown. The only unsafe
case would be if you have a URL that starts with "http://"
but curl interprets as another protocol. That seems like an
unlikely failure mode (and we are still protected by our
base CURLOPT_PROTOCOL setting, so the worst you could do is
trigger one of https, ftp, or ftps).

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

transport: add from_user parameter to is_transport_allowed

Add a from_user parameter to is_transport_allowed() to allow http to be
able to distinguish between protocol restrictions for redirects versus
initial requests. CURLOPT_REDIR_PROTOCOLS can now be set differently
from CURLOPT_PROTOCOLS to disallow use of protocols with the "user"
policy in redirects.

This change allows callers to query if a transport protocol is allowed,
given that the caller knows that the protocol is coming from the user
(1) or not from the user (0) such as redirects in libcurl. If unknown a
-1 should be provided which falls back to reading
`GIT_PROTOCOL_FROM_USER` to determine if the protocol came from the
user.

Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

http: create function to get curl allowed protocols

Move the creation of an allowed protocols whitelist to a helper
function. This will be useful when we need to compute the set of
allowed protocols differently for normal and redirect cases.

Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

transport: add protocol policy config option

Previously the `GIT_ALLOW_PROTOCOL` environment variable was used to
specify a whitelist of protocols to be used in clone/fetch/push
commands. This patch introduces new configuration options for more
fine-grained control for allowing/disallowing protocols. This also has
the added benefit of allowing easier construction of a protocol
whitelist on systems where setting an environment variable is
non-trivial.

Now users can specify a policy to be used for each type of protocol via
the 'protocol.<name>.allow' config option. A default policy for all
unconfigured protocols can be set with the 'protocol.allow' config
option. If no user configured default is made git will allow known-safe
protocols (http, https, git, ssh, file), disallow known-dangerous
protocols (ext), and have a default policy of `user` for all other
protocols.

The supported policies are `always`, `never`, and `user`. The `user`
policy can be used to configure a protocol to be usable when explicitly
used by a user, while disallowing it for commands which run
clone/fetch/push commands without direct user intervention (e.g.
recursive initialization of submodules). Commands which can potentially
clone/fetch/push from untrusted repositories without user intervention
can export `GIT_PROTOCOL_FROM_USER` with a value of '0' to prevent
protocols configured to the `user` policy from being used.

Fix remote-ext tests to use the new config to allow the ext
protocol to be tested.

Based on a patch by Jeff King <peff@peff.net>

Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

http: always warn if libcurl version is too old

Always warn if libcurl version is too old because:

1. Even without a protocol whitelist, newer versions of curl have all
non-standard protocols disabled by default.
2. A future patch will introduce default "known-good" and "known-bad"
protocols which are allowed/disallowed by 'is_transport_allowed'
which older version of libcurl can't respect.

Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

lib-proto-disable: variable name fix

The test_proto function assigns the positional parameters to named
variables, but then still refers to "$desc" as "$1". Using $desc is
more readable and less error-prone.

Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Revert "sequencer: remove useless get_dir() function"

This reverts commit 39784cd3620cc47415c9010ec58a9616f040125c.

The function had only one caller when the "remove useless" was
written, but another topic will soon make heavy use of it and more
importantly the function will return different paths depending on
the value in opts.

i18n: difftool: mark warnings for translation

Signed-off-by: Vasco Almeida <vascomalmeida@sapo.pt>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

i18n: send-email: mark composing message for translation

When composing an e-mail, there is a message for the user whose lines
begin in "GIT:" that can be marked for translation.

Signed-off-by: Vasco Almeida <vascomalmeida@sapo.pt>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

i18n: send-email: mark string with interpolation for translation

Mark warnings, errors and other messages that are interpolated for
translation.

We call sprintf() before calling die() and in few other circumstances in
order to replace the values on the placeholders.

Signed-off-by: Vasco Almeida <vascomalmeida@sapo.pt>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

i18n: send-email: mark warnings and errors for translation

Mark warnings, errors and other messages for translation.

Signed-off-by: Vasco Almeida <vascomalmeida@sapo.pt>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

i18n: send-email: mark strings for translation

Mark strings often displayed to the user for translation.

Signed-off-by: Vasco Almeida <vascomalmeida@sapo.pt>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

i18n: add--interactive: mark status words for translation

Mark words 'nothing', 'unchanged' and 'binary' used to display what has
been staged or not, in "git add -i" status command.

Alternatively one could mark N__('nothing') no-op in order to
xgettext(1) extract the string and then trigger the translation at run
time only with __($print->{FILE}), but that has the side effect of triggering
retrieval of translations for the changes indicator too (e.g. +2/-1)
which may or may not be a problem.

To avoid that potential problem, mark only where there is certain to
trigger translation only of those words but in this case we must also
retrieve the translation for the eq tests, since the value assigned was
of the translation, not the English source.

Signed-off-by: Vasco Almeida <vascomalmeida@sapo.pt>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

i18n: add--interactive: remove %patch_modes entries

Remove unnecessary entries from %patch_modes. After the i18n conversion,
these entries are not used anymore.

Signed-off-by: Vasco Almeida <vascomalmeida@sapo.pt>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

i18n: add--interactive: mark edit_hunk_manually message for translation

Mark message of edit_hunk_manually displayed in the editing file when
user chooses 'e' option. The message had to be unfolded to allow
translation of the $participle verb.

Some messages end up being exactly the same for some use cases, but
left it for easier change in the future, e.g., wanting to change wording
of one particular use case.

The comment character is now used according to the git configuration
core.commentchar.

Signed-off-by: Vasco Almeida <vascomalmeida@sapo.pt>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

i18n: add--interactive: i18n of help_patch_cmd

Mark help message of help_patch_cmd for translation. The message must
be unfolded to be free of variables so we can have high quality
translations.

Signed-off-by: Vasco Almeida <vascomalmeida@sapo.pt>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

i18n: add--interactive: mark patch prompt for translation

Mark prompt message assembled in place for translation, unfolding each
use case for each entry in the %patch_modes hash table.

Previously, this script relied on whether $patch_mode was set to run the
command patch_update_cmd() or show status and loop the main loop. Now,
it uses $cmd to indicate we must run patch_update_cmd() and $patch_mode
is used to tell which flavor of the %patch_modes are we on. This is
introduced in order to be able to mark and unfold the message prompt
knowing in which context we are.

The tracking of context was done previously by point %patch_mode_flavour
hash table to the correct entry of %patch_modes, focusing only on value
of %patch_modes. Now, we are also interested in the key ('staged',
'stash', 'checkout_head', ...).

Signed-off-by: Vasco Almeida <vascomalmeida@sapo.pt>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

i18n: add--interactive: mark plural strings

Mark plural strings for translation. Unfold each action case in one
entire sentence.

Pass new keyword for xgettext to extract.

Update test to include new subroutine __n() for plural strings handling.

Update documentation to include a description of the new __n()
subroutine.

Signed-off-by: Vasco Almeida <vascomalmeida@sapo.pt>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

i18n: clean.c: match string with git-add--interactive.perl

Change strings for help to match the ones in git-add--interactive.perl.
The strings now represent one entry to translate each rather then two
entries each different only by an ending newline character.

Signed-off-by: Vasco Almeida <vascomalmeida@sapo.pt>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

i18n: add--interactive: mark strings with interpolation for translation

Since at this point Git::I18N.perl lacks support for Perl i18n
placeholder substitution, use of sprintf following die or error_msg is
necessary for placeholder substitution take place.

Signed-off-by: Vasco Almeida <vascomalmeida@sapo.pt>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

i18n: add--interactive: mark simple here-documents for translation

Mark messages in here-documents without interpolation for translation.

The here-document delimiter \EOF, which is the same as 'EOF', indicates
that the text is to be treated literally without interpolation of its
content. Unfortunately xgettext is not able to extract here-documents
delimited with \EOF but it is with delimiter enclosed in single quotes.
So change \EOF to 'EOF', although in this case does not make
difference what variation of here-document to use since there is nothing
to interpolate.

Signed-off-by: Vasco Almeida <vascomalmeida@sapo.pt>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

i18n: add--interactive: mark strings for translation

Mark simple strings (without interpolation) for translation.

Brackets around first parameter of ternary operator is necessary because
otherwise xgettext fails to extract strings marked for translation from
the rest of the file.

Signed-off-by: Vasco Almeida <vascomalmeida@sapo.pt>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Git.pm: add subroutines for commenting lines

Add subroutines prefix_lines and comment_lines.

Signed-off-by: Vasco Almeida <vascomalmeida@sapo.pt>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

merge: ensure '--abort' option takes no arguments

Like '--continue', the '--abort' option doesn't make any sense with
other options or arguments to 'git merge' so ensure that none are
present.

Signed-off-by: Chris Packham <judge.packham@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

completion: add --continue option for merge

Add 'git merge --continue' option when completing.

Signed-off-by: Chris Packham <judge.packham@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

merge: add '--continue' option as a synonym for 'git commit'

Teach 'git merge' the --continue option which allows 'continuing' a
merge by completing it. The traditional way of completing a merge after
resolving conflicts is to use 'git commit'. Now with commands like 'git
rebase' and 'git cherry-pick' having a '--continue' option adding such
an option to 'git merge' presents a consistent UI.

Signed-off-by: Chris Packham <judge.packham@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

parse-options: print "fatal:" before usage_msg_opt()

Programs may use usage_msg_opt() to print a brief message
followed by the program usage, and then exit. The message
isn't prefixed at all, though, so it doesn't match our usual
error output and is easy to overlook:

$ git clone 1 2 3
Too many arguments.

usage: git clone [<options>] [--] <repo> [<dir>]

-v, --verbose be more verbose
-q, --quiet be more quiet
--progress force progress reporting
-n, --no-checkout don't create a checkout
--bare create a bare repository
[...and so on for another 31 lines...]

It looks especially bad when the message starts with an
option, like:

$ git replace -e
-e needs exactly one argument

usage: git replace [-f] <object> <replacement>
or: git replace [-f] --edit <object>
[...etc...]

Let's put our usual "fatal:" prefix in front of it.

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

Makefile: exclude contrib from FIND_SOURCE_FILES

When you're working on the git project, you're unlikely to
care about random bits in contrib/ (e.g., you would not want
to jump to the copy of xmalloc in the wincred credential
helper). Nobody has really complained because there are
relatively few C files in contrib.

Now that we're matching shell scripts, too, we get quite a
few more hits, especially in the obsolete contrib/examples
directory. Looking for usage() should turn up the one in
git-sh-setup, not in some long-dead version of git-clone.

Let's just exclude all of contrib. Any specific projects
there which are big enough to want tags can generate them
separately.

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

Makefile: match shell scripts in FIND_SOURCE_FILES

We feed FIND_SOURCE_FILES to ctags to help developers
navigate to particular functions, but we only feed C source
code. The same feature can be helpful when working with
shell scripts (especially the test suite). Modern versions
of ctags know how to parse shell scripts; we just need to
feed the filenames to it.

This patch specifically avoids including the individual test
scripts themselves. Those are unlikely to be of interest,
and there are a lot of them to process. It does pick up
test-lib.sh and test-lib-functions.sh.

Note that our negative pathspec already excludes the
individual scripts for the ls-files case, but we need to
loosen the `find` rule to match it.

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

Makefile: exclude test cruft from FIND_SOURCE_FILES

The test directory may contain three types of files that
match our patterns:

1. Helper programs in t/helper.

2. Sample data files (e.g., t/t4051/hello.c).

3. Untracked cruft in trash directories and t/perf/build.

We want to match (1), but not the other two, as they just
clutter up the list.

For the ls-files method, we can drop (2) with a negative
pathspec. We do not have to care about (3), since ls-files
will not list untracked files.

For `find`, we can match both cases with `-prune` patterns.

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

Makefile: reformat FIND_SOURCE_FILES

As we add to this in future commits, the formatting is going
to make it harder and harder to read. Let's write it more as
we would in a shell script, putting each logical block on
its own line.

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

unicode_width.h: update the width tables to Unicode 9.0

Rerunning update-unicode.sh that we fixed in the previous commits
produces these new tables.

Signed-off-by: Beat Bolli <dev+git@drbeat.li>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

update_unicode.sh: remove the plane filter

The uniset upstream has accepted my patches that eliminate the Unicode
plane offsets from the output in '--32' mode.

Remove the corresponding filter in update_unicode.sh.

This also fixes the issue that the plane offsets were not removed from
the second uniset call.

Signed-off-by: Beat Bolli <dev+git@drbeat.li>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

update_unicode.sh: automatically download newer definition files

Checking just for the unicode data files' existence is not sufficient;
we should also download them if a newer version exists on the Unicode
consortium's servers. Option -N of wget does this nicely for us.

Reviewed-by: Torsten Bögershausen <tboegi@web.de>
Signed-off-by: Beat Bolli <dev+git@drbeat.li>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

update_unicode.sh: pin the uniset repo to a known good commit

The uniset upstream has added more commits that for example change the
hexadecimal output in '--32' mode to decimal. Let's pin the repo to a
commit that still outputs the width tables in the format we want.

Signed-off-by: Beat Bolli <dev+git@drbeat.li>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

update_unicode.sh: remove an unnecessary subshell level

After the move into contrib/update-unicode, we no longer create the
unicode directory to have a clean working folder. Instead, the directory
of the script is used. This means that the subshell can be removed.

Signed-off-by: Beat Bolli <dev+git@drbeat.li>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

update_unicode.sh: move it into contrib/update-unicode

As it's used only by a tiny minority of the Git developer population,
this script does not belong into the main Git source directory.

Move it into contrib/ and adjust the paths to account for the new
location.

Signed-off-by: Beat Bolli <dev+git@drbeat.li>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

git-p4: support git worktrees

git-p4 would attempt to find the git directory using
its own specific code, which did not know about git
worktrees.

Rework it to use "git rev-parse --git-dir" instead.

Add test cases for worktree usage and specifying
git directory via --git-dir and $GIT_DIR.

Signed-off-by: Luke Diamand <luke@diamand.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Early fixes for 2.11.x series

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

Merge branch 'ew/svn-fixes'

* ew/svn-fixes:
git-svn: document useLogAuthor and addAuthorFrom config keys
git-svn: allow "0" in SVN path components

Merge branch 'js/mingw-isatty'

We often decide if a session is interactive by checking if the
standard I/O streams are connected to a TTY, but isatty() emulation
on Windows incorrectly returned true if it is used on NUL (i.e. an
equivalent to /dev/null). This has been fixed.

* js/mingw-isatty:
mingw: intercept isatty() to handle /dev/null as Git expects it

t5547-push-quarantine: run the path separator test on Windows, too

To perform the test case on Windows in a way that corresponds to the
POSIX version, inject the semicolon in a directory name.

Typically, an absolute POSIX style path, such as the one in $PWD, is
translated into a Windows style path by bash when it invokes git.exe.
However, the presence of the semicolon suppresses this translation;
but the untranslated POSIX style path is useless for git.exe.
Therefore, instead of $PWD pass the Windows style path that $(pwd)
produces.

Signed-off-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t3600: slightly modernize style

Remove the space between redirection and file name.
Also remove unnecessary invocations of subshells, such as

(cd submod &&
echo X >untracked
) &&

as there is no point of having the shell for functional purposes.
In case of a single Git command use the `-C` option to let Git cd into
the directory.

Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

tmp-objdir: quote paths we add to alternates

Commit 722ff7f87 (receive-pack: quarantine objects until
pre-receive accepts, 2016-10-03) regressed pushes to
repositories with colon (or semi-colon in Windows in them)
because it adds the repository's main object directory to
GIT_ALTERNATE_OBJECT_DIRECTORIES. The receiver interprets
the colon as a delimiter, not as part of the path, and
index-pack is unable to find objects which it needs to
resolve deltas.

The previous commit introduced a quoting mechanism for the
alternates list; let's use it here to cover this case. We'll
avoid quoting when we can, though. This alternate setup is
also used when calling hooks, so it's possible that the user
may call older git implementations which don't understand
the quoting mechanism. By quoting only when necessary, this
setup will continue to work unless the user _also_ has a
repository whose path contains the delimiter.

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

alternates: accept double-quoted paths

We read lists of alternates from objects/info/alternates
files (delimited by newline), as well as from the
GIT_ALTERNATE_OBJECT_DIRECTORIES environment variable
(delimited by colon or semi-colon, depending on the
platform).

There's no mechanism for quoting the delimiters, so it's
impossible to specify an alternate path that contains a
colon in the environment, or one that contains a newline in
a file. We've lived with that restriction for ages because
both alternates and filenames with colons are relatively
rare, and it's only a problem when the two meet. But since
722ff7f87 (receive-pack: quarantine objects until
pre-receive accepts, 2016-10-03), which builds on the
alternates system, every push causes the receiver to set
GIT_ALTERNATE_OBJECT_DIRECTORIES internally.

It would be convenient to have some way to quote the
delimiter so that we can represent arbitrary paths.

The simplest thing would be an escape character before a
quoted delimiter (e.g., "\:" as a literal colon). But that
creates a backwards compatibility problem: any path which
uses that escape character is now broken, and we've just
shifted the problem. We could choose an unlikely escape
character (e.g., something from the non-printable ASCII
range), but that's awkward to use.

Instead, let's treat names as unquoted unless they begin
with a double-quote, in which case they are interpreted via
our usual C-stylke quoting rules. This also breaks
backwards-compatibility, but in a smaller way: it only
matters if your file has a double-quote as the very _first_
character in the path (whereas an escape character is a
problem anywhere in the path). It's also consistent with
many other parts of git, which accept either a bare pathname
or a double-quoted one, and the sender can choose to quote
or not as required.

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

Merge branch 'jk/alt-odb-cleanup' into jk/quote-env-path-list-component

* jk/alt-odb-cleanup:
alternates: re-allow relative paths from environment

date-formats.txt: Typo fix

Last time I checked, I was living in the UTC+01:00 time zone. UTC+02:00
would be Central European _Summer_ Time.

Signed-off-by: Luis Ressel <aranea@aixah.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

git-svn: document useLogAuthor and addAuthorFrom config keys

We've always supported these config keys in git-svn,
so document them so users won't have to respecify them
on every invocation.

Reported-by: Juergen Kosel <juergen.kosel@gmx.de>
Signed-off-by: Eric Wong <e@80x24.org>

git-svn: allow "0" in SVN path components

Blindly checking a path component for falsiness is unwise, as
"0" is false to Perl, but a valid pathname component for SVN
(or any filesystem).

Found via random code reading.

Signed-off-by: Eric Wong <e@80x24.org>

submodule--helper: set alternateLocation for cloned submodules

In 31224cbdc7 (clone: recursive and reference option triggers
submodule alternates, 2016-08-17) a mechanism was added to
have submodules referenced. It did not address _nested_
submodules, however.

This patch makes all not just the root repository, but also
all submodules (recursively) have submodule.alternateLocation
and submodule.alternateErrorStrategy configured, making Git
search for possible alternates for nested submodules as well.

As submodule's alternate target does not end in .git/objects
(rather .git/modules/qqqqqq/objects), this alternate target
path restriction for in add_possible_reference_from_superproject
relates from "*.git/objects" to just */objects".

New tests have been added to t7408-submodule-reference.

Signed-off-by: Vitaly _Vi Shukela <vi0oss@gmail.com>
Reviewed-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

mergetools: fix xxdiff hotkeys

xxdiff was using a mix of "Ctrl-<key>" and "Ctrl+<key>" hotkeys.
The dashed "-" form is not accepted by newer xxdiff versions.
Use the plus "+" form only.

Signed-off-by: David Aguilar <davvid@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

difftool: rename variables for consistency

Always call the list of files @files.
Always call the worktree $worktree.

Signed-off-by: David Aguilar <davvid@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

difftool: chdir as early as possible

Make difftool chdir to the top-level of the repository as soon as it can
so that we can simplify how paths are handled. Replace construction of
absolute paths via string concatenation with relative paths wherever
possible. The bulk of the code no longer needs to use absolute paths.

Signed-off-by: David Aguilar <davvid@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

difftool: sanitize $workdir as early as possible

The double-slash fixup on the $workdir variable was being
performed just-in-time to avoid double-slashes in symlink
targets, but the rest of the code was silently using paths with
embedded "//" in them.

A recent user-reported error message contained double-slashes.
Eliminate the issue by sanitizing inputs as soon as they arrive.

Signed-off-by: David Aguilar <davvid@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

difftool: fix dir-diff index creation when in a subdirectory

9ec26e7977 (difftool: fix argument handling in subdirs, 2016-07-18)
corrected how path arguments are handled in a subdirectory, but
it introduced a regression in how entries outside of the
subdirectory are handled by dir-diff.

When preparing the right-side of the diff we only include the
changed paths in the temporary area.

The left side of the diff is constructed from a temporary
index that is built from the same set of changed files, but it
was being constructed from within the subdirectory. This is a
problem because the indexed paths are toplevel-relative, and
thus they were not getting added to the index.

Teach difftool to chdir to the toplevel of the repository before
preparing its temporary indexes. This ensures that all of the
toplevel-relative paths are valid.

Add test cases to more thoroughly exercise this scenario.

Reported-by: Frank Becker <fb@mooflu.com>
Signed-off-by: David Aguilar <davvid@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

mingw: intercept isatty() to handle /dev/null as Git expects it

When Git's source code calls isatty(), it really asks whether the
respective file descriptor is connected to an interactive terminal.

Windows' _isatty() function, however, determines whether the file
descriptor is associated with a character device. And NUL, Windows'
equivalent of /dev/null, is a character device.

Which means that for years, Git mistakenly detected an associated
interactive terminal when being run through the test suite, which
almost always redirects stdin, stdout and stderr to /dev/null.

This bug only became obvious, and painfully so, when the new
bisect--helper entered the `pu` branch and made the automatic build & test
time out because t6030 was waiting for an answer.

For details, see

https://msdn.microsoft.com/en-us/library/f4s0ddew.aspx

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

ref-filter: add support to display trailers as part of contents

Add %(trailers) and %(contents:trailers) to display the trailers as
interpreted by trailer_info_get. Update documentation and add a test for
the new feature.

Signed-off-by: Jacob Keller <jacob.keller@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

pretty: add %(trailers) format for displaying trailers of a commit message

Recent patches have expanded on the trailers.c code and we have the
builtin commant git-interpret-trailers which can be used to add or
modify trailer lines. However, there is no easy way to simply display
the trailers of a commit message.

Add support for %(trailers) format modifier which will use the
trailer_info_get() calls to read trailers in an identical way as git
interpret-trailers does. Use a long format option instead of a short
name so that future work can more easily unify ref-filter and pretty
formats.

Add documentation and tests for the same.

Signed-off-by: Jacob Keller <jacob.keller@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

rebase: add --quit to cleanup rebase, leave everything else untouched

There are occasions when you decide to abort an in-progress rebase and
move on to do something else but you forget to do "git rebase --abort"
first. Or the rebase has been in progress for so long you forgot about
it. By the time you realize that (e.g. by starting another rebase)
it's already too late to retrace your steps. The solution is normally

rm -r .git/<some rebase dir>

and continue with your life. But there could be two different
directories for <some rebase dir> (and it obviously requires some
knowledge of how rebase works), and the ".git" part could be much
longer if you are not at top-dir, or in a linked worktree. And
"rm -r" is very dangerous to do in .git, a mistake in there could
destroy object database or other important data.

Provide "git rebase --quit" for this use case, mimicking a precedent
that is "git cherry-pick --quit".

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

doc: omit needless "for"

What was intended was perhaps "... plumbing does for you" ("you" added), but
simply omitting the word "for" is more terse and gets the intended point across
just as well, if not more so.

I originally went with the approach of writing "for you", but Junio C
Hamano suggested this approach instead.

Signed-off-by: Kristoffer Haugsbakk <kristoffer.haugsbakk@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

doc: make the intent of sentence clearer

By adding the word "just", which might have been accidentally omitted.

Adding the word "just" makes it clear that the point is to *not* do an
octopus merge simply because you *can* do it. In other words, you
should have a reason for doing it beyond simply having two (seemingly)
independent commits that you need to merge into another branch, since
it's not always the best approach.

The previous sentence made it look more like it was trying to say that
you shouldn't do an octopus merge *because* you can do an octopus merge.
Although this interpretation doesn't make sense and the rest of the
paragraph makes the intended meaning clear, this adjustment should make
the intent of the sentence more immediately clear to the reader.

Signed-off-by: Kristoffer Haugsbakk <kristoffer.haugsbakk@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

doc: add verb in front of command to run

Instead of using the command 'git clone' as a verb, use "run" as the
verb indicating the action of executing the command 'git clone'.

Signed-off-by: Kristoffer Haugsbakk <kristoffer.haugsbakk@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

doc: add articles (grammar)

Add definite and indefinite articles in three places where they were
missing.

- Use "the" in front of a directory name
- Use "the" in front of "style of cooperation"
- Use an indefinite article in front of "CVS background"

Signed-off-by: Kristoffer Haugsbakk <kristoffer.haugsbakk@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

sequencer: remove useless get_dir() function

This function is used only once, for the removal of the
directory. It is not used for the creation of the directory nor
anywhere else.

Signed-off-by: Stephan Beyer <s-beyer@gmx.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

sequencer: make sequencer abort safer

In contrast to "git am --abort", a sequencer abort did not check
whether the current HEAD is the one that is expected. This can lead
to loss of work (when not spotted and resolved using reflog before
the garbage collector chimes in).

This behavior is now changed by mimicking "git am --abort". The
abortion is done but HEAD is not changed when the current HEAD is
not the expected HEAD.

A new file "sequencer/abort-safety" is added to save the expected
HEAD.

The new behavior is only active when --abort is invoked on multiple
picks. The problem does not occur for the single-pick case because
it is handled differently.

Signed-off-by: Stephan Beyer <s-beyer@gmx.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t3510: test that cherry-pick --abort does not unsafely change HEAD

Signed-off-by: Stephan Beyer <s-beyer@gmx.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

commit: remove 'Clever' message for --only --amend

The behavior is now documented; more importantly, rewarding the user
with a "Wow, you are clever" praise afterwards is not an effective
way to advertise the feature--at that point the user already knows.

Signed-off-by: Andreas Krey <a.krey@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff: handle --no-abbrev in no-index case

There are two different places where the --no-abbrev option is parsed,
and two different places where SHA-1s are abbreviated. We normally parse
--no-abbrev with setup_revisions(), but in the no-index case, "git diff"
calls diff_opt_parse() directly, and diff_opt_parse() didn't handle
--no-abbrev until now. (It did handle --abbrev, however.) We normally
abbreviate SHA-1s with find_unique_abbrev(), but commit 4f03666 ("diff:
handle sha1 abbreviations outside of repository, 2016-10-20) recently
introduced a special case when you run "git diff" outside of a
repository.

setup_revisions() does also call diff_opt_parse(), but not for --abbrev
or --no-abbrev, which it handles itself. setup_revisions() sets
rev_info->abbrev, and later copies that to diff_options->abbrev. It
handles --no-abbrev by setting abbrev to zero. (This change doesn't
touch that.)

Setting abbrev to zero was broken in the outside-of-a-repository special
case, which until now resulted in a truly zero-length SHA-1, rather than
taking zero to mean do not abbreviate. The only way to trigger this bug,
however, was by running "git diff --raw" without either the --abbrev or
--no-abbrev options, because 1) without --raw it doesn't respect abbrev
(which is bizarre, but has been that way forever), 2) we silently clamp
--abbrev=0 to MINIMUM_ABBREV, and 3) --no-abbrev wasn't handled until
now.

The outside-of-a-repository case is one of three no-index cases. The
other two are when one of the files you're comparing is outside of the
repository you're in, and the --no-index option.

Signed-off-by: Jack Bates <jack@nottheoilrig.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

difftool: fix dir-diff index creation when in a subdirectory

9ec26e7977 (difftool: fix argument handling in subdirs, 2016-07-18)
corrected how path arguments are handled in a subdirectory, but
it introduced a regression in how entries outside of the
subdirectory are handled by dir-diff.

When preparing the right-side of the diff we only include the
changed paths in the temporary area.

The left side of the diff is constructed from a temporary
index that is built from the same set of changed files, but it
was being constructed from within the subdirectory. This is a
problem because the indexed paths are toplevel-relative, and
thus they were not getting added to the index.

Teach difftool to chdir to the toplevel of the repository before
preparing its temporary indexes. This ensures that all of the
toplevel-relative paths are valid.

Add test cases to more thoroughly exercise this scenario.

Reported-by: Frank Becker <fb@mooflu.com>
Signed-off-by: David Aguilar <davvid@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

am: change safe_to_abort()'s not rewinding error into a warning

The error message tells the user that something went terribly wrong
and the --abort could not be performed. But the --abort is performed,
only without rewinding. By simply changing the error into a warning,
we indicate the user that she must not try something like
"git am --abort --force", instead she just has to check the HEAD.

Signed-off-by: Stephan Beyer <s-beyer@gmx.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

am: fix filename in safe_to_abort() error message

Signed-off-by: Stephan Beyer <s-beyer@gmx.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

shallow.c: remove useless code

Some context before we talk about the removed code.

This paint_down() is part of step 6 of 58babff (shallow.c: the 8 steps
to select new commits for .git/shallow - 2013-12-05). When we fetch from
a shallow repository, we need to know if one of the new/updated refs
needs new "shallow commits" in .git/shallow (because we don't have
enough history of those refs) and which one.

The question at step 6 is, what (new) shallow commits are required in
other to maintain reachability throughout the repository _without_
cutting our history short? To answer, we mark all commits reachable from
existing refs with UNINTERESTING ("rev-list --not --all"), mark shallow
commits with BOTTOM, then for each new/updated refs, walk through the
commit graph until we either hit UNINTERESTING or BOTTOM, marking the
ref on the commit as we walk.

After all the walking is done, we check the new shallow commits. If we
have not seen any new ref marked on a new shallow commit, we know all
new/updated refs are reachable using just our history and .git/shallow.
The shallow commit in question is not needed and can be thrown away.

So, the code.

The loop here (to walk through commits) is basically

1. get one commit from the queue
2. ignore if it's SEEN or UNINTERESTING
3. mark it
4. go through all the parents and..
5a. mark it if it's never marked before
5b. put it back in the queue

What we do in this patch is drop step 5a because it is not
necessary. The commit being marked at 5a is put back on the queue, and
will be marked at step 3 at the next iteration. The only case it will
not be marked is when the commit is already marked UNINTERESTING (5a
does not check this), which will be ignored at step 2.

But we don't care about refs marking on UNINTERESTING. We care about the
marking on _shallow commits_ that are not reachable from our current
history (and having UNINTERESTING on it means it's reachable). So it's
ok for an UNINTERESTING not to be ref-marked.

Reported-by: Rasmus Villemoes <rv@rasmusvillemoes.dk>
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

shallow.c: bit manipulation tweaks

First of all, 1 << 31 is technically undefined behaviour, so let's just
use an unsigned literal.

If i is 'signed int' and gcc doesn't know that i is positive, gcc
generates code to compute the C99-mandated values of "i / 32" and "i %
32", which is a lot more complicated than simple a simple shifts/mask.

The only caller of paint_down actually passes an "unsigned int" value,
but the prototype of paint_down causes (completely well-defined)
conversion to signed int, and gcc has no way of knowing that the
converted value is non-negative. Just make the id parameter unsigned.

In update_refstatus, the change in generated code is much smaller,
presumably because gcc is smart enough to see that i starts as 0 and is
only incremented, so it is allowed (per the UD of signed overflow) to
assume that i is always non-negative. But let's just help less smart
compilers generate good code anyway.

Signed-off-by: Rasmus Villemoes <rv@rasmusvillemoes.dk>
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

shallow.c: avoid theoretical pointer wrap-around

The expression info->free+size is technically undefined behaviour in
exactly the case we want to test for. Moreover, the compiler is likely
to translate the expression to

(unsigned long)info->free + size > (unsigned long)info->end

where there's at least a theoretical chance that the LHS could wrap
around 0, giving a false negative.

This might as well be written using pointer subtraction avoiding these
issues.

Signed-off-by: Rasmus Villemoes <rv@rasmusvillemoes.dk>
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

shallow.c: make paint_alloc slightly more robust

paint_alloc() allocates a big block of memory and splits it into
smaller, fixed size, chunks of memory whenever it's called. Each chunk
contains enough bits to present all "new refs" [1] in a fetch from a
shallow repository.

We do not check if the new "big block" is smaller than the requested
memory chunk though. If it happens, we'll happily pass back a memory
region smaller than expected. Which will lead to problems eventually.

A normal fetch may add/update a dozen new refs. Let's stay on the
"reasonably extreme" side and say we need 16k refs (or bits from
paint_alloc's perspective). Each chunk of memory would be 2k, much
smaller than the memory pool (512k).

So, normally, the under-allocation situation should never happen. A bad
guy, however, could make a fetch that adds more than 4m new/updated refs
to this code which results in a memory chunk larger than pool size.
Check this case and abort.

Noticed-by: Rasmus Villemoes <rv@rasmusvillemoes.dk>
Reviewed-by: Jeff King <peff@peff.net>
[1] Details are in commit message of 58babff (shallow.c: the 8 steps to
select new commits for .git/shallow - 2013-12-05), step 6.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

shallow.c: stop abusing COMMIT_SLAB_SIZE for paint_info's memory pools

We need to allocate a "big" block of memory in paint_alloc(). The exact
size does not really matter. But the pool size has no relation with
commit-slab. Stop using that macro here.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

shallow.c: rename fields in paint_info to better express their purposes

paint_alloc() is basically malloc(), tuned for allocating a fixed number
of bits on every call without worrying about freeing any individual
allocation since all will be freed at the end. It does it by allocating
a big block of memory every time it runs out of "free memory". "slab" is
a poor choice of name, at least poorer than "pool".

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

lockfile: LOCK_REPORT_ON_ERROR

The "libify sequencer" topic stopped passing the die_on_error option
to hold_locked_index(), and this lost an error message from "git
merge --ff-only $commit" when there are competing updates in
progress.

The command still exits with a non-zero status, but that is not of
much help for an interactive user. The last thing the command says
is "Updating $from..$to". We used to follow it with a big error
message that makes it clear that "merge --ff-only" did not succeed.

What is sad is that we should have noticed this regression while
reviewing the change. It was clear that the update to the
checkout_fast_forward() function made a failing hold_locked_index()
silent, but the only caller of the checkout_fast_forward() function
had this comment:

if (checkout_fast_forward(from, to, 1))
- exit(128); /* the callee should have complained already */
+ return -1; /* the callee should have complained already */

which clearly contradicted the assumption X-<.

Add a new option LOCK_REPORT_ON_ERROR that can be passed instead of
LOCK_DIE_ON_ERROR to the hold_lock*() family of functions and teach
checkout_fast_forward() to use it to fix this regression.

After going thourgh all calls to hold_lock*() family of functions
that used to pass LOCK_DIE_ON_ERROR but were modified to pass 0 in
the "libify sequencer" topic "git show --first-parent 2a4062a4a8",
it appears that this is the only one that has become silent. Many
others used to give detailed report that talked about "there may be
competing Git process running" but with the series merged they now
only give a single liner "Unable to lock ...", some of which may
have to be tweaked further, but at least they say something, unlike
the one this patch fixes.

Reported-by: Robbie Iannucci <iannucci@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

hold_locked_index(): align error handling with hold_lockfile_for_update()

Callers of the hold_locked_index() function pass 0 when they want to
prepare to write a new version of the index file without wishing to
die or emit an error message when the request fails (e.g. somebody
else already held the lock), and pass 1 when they want the call to
die upon failure.

This option is called LOCK_DIE_ON_ERROR by the underlying lockfile
API, and the hold_locked_index() function translates the paramter to
LOCK_DIE_ON_ERROR when calling the hold_lock_file_for_update().

Replace these hardcoded '1' with LOCK_DIE_ON_ERROR and stop
translating. Callers other than the ones that are replaced with
this change pass '0' to the function; no behaviour change is
intended with this patch.

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

Among the callers of hold_locked_index() that passes 0:

- diff.c::refresh_index_quietly() at the end of "git diff" is an
opportunistic update; it leaks the lockfile structure but it is
just before the program exits and nobody should care.

- builtin/describe.c::cmd_describe(),
builtin/commit.c::cmd_status(),
sequencer.c::read_and_refresh_cache() are all opportunistic
updates and they are OK.

- builtin/update-index.c::cmd_update_index() takes a lock upfront
but we may end up not needing to update the index (i.e. the
entries may be fully up-to-date), in which case we do not need to
issue an error upon failure to acquire the lock. We do diagnose
and die if we indeed need to update, so it is OK.

- wt-status.c::require_clean_work_tree() IS BUGGY. It asks
silence, does not check the returned value. Compare with
callsites like cmd_describe() and cmd_status() to notice that it
is wrong to call update_index_if_able() unconditionally.

wt-status: implement opportunisitc index update correctly

The require_clean_work_tree() function calls hold_locked_index()
with die_on_error=0 to signal that it is OK if it fails to obtain
the lock, but unconditionally calls update_index_if_able(), which
will try to write into fd=-1.

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

stash: prefer plumbing over git-diff

When creating a stash, we need to look at the diff between
the working tree and HEAD, and do so using the git-diff
porcelain. Because git-diff enables porcelain config like
renames by default, this causes at least one problem. The
--name-only format will not mention the source side of a
rename, meaning we will fail to stash a deletion that is
part of a rename.

We could fix that case by passing --no-renames, but this is
a symptom of a larger problem. We should be using the
diff-index plumbing here, which does not have renames
enabled by default, and also does not respect any
potentially confusing config options.

Reported-by: Matthew Patey <matthew.patey2167@gmail.com>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

xdiff: drop XDL_FAST_HASH

The xdiff code hashes every line of both sides of a diff,
and then compares those hashes to find duplicates. The
overall performance depends both on how fast we can compute
the hashes, but also on how many hash collisions we see.

The idea of XDL_FAST_HASH is to speed up the hash
computation. But the generated hashes have worse collision
behavior. This means that in some cases it speeds diffs up
(running "git log -p" on git.git improves by ~8% with it),
but in others it can slow things down. One pathological case
saw over a 100x slowdown[1].

There may be a better hash function that covers both
properties, but in the meantime we are better off with the
original hash. It's slightly slower in the common case, but
it has fewer surprising pathological cases.

[1] http://public-inbox.org/git/20141222041944.GA441@peff.net/

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

http-walker: complain about non-404 loose object errors

Since commit 17966c0a6 (http: avoid disconnecting on 404s
for loose objects, 2016-07-11), we turn off curl's
FAILONERROR option and instead manually deal with failing
HTTP codes.

However, the logic to do so only recognizes HTTP 404 as a
failure. This is probably the most common result, but if we
were to get another code, the curl result remains CURLE_OK,
and we treat it as success. We still end up detecting the
failure when we try to zlib-inflate the object (which will
fail), but instead of reporting the HTTP error, we just
claim that the object is corrupt.

Instead, let's catch anything in the 300's or above as an
error (300's are redirects which are not an error at the
HTTP level, but are an indication that we've explicitly
disabled redirects, so we should treat them as such; we
certainly don't have the resulting object content).

Note that we also fill in req->errorstr, which we didn't do
before. Without FAILONERROR, curl will not have filled this
in, and it will remain a blank string. This never mattered
for the 404 case, because in the logic below we hit the
"missing_target()" branch and print nothing. But for other
errors, we'd want to say _something_, if only to fill in the
blank slot in the error message.

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

Merge branch 'ew/http-walker' into jk/http-walker-limit-redirect

* ew/http-walker:
list: avoid incompatibility with *BSD sys/queue.h
http-walker: reduce O(n) ops with doubly-linked list
http: avoid disconnecting on 404s for loose objects
http-walker: remove unused parameter from fetch_object

http: treat http-alternates like redirects

The previous commit made HTTP redirects more obvious and
tightened up the default behavior. However, there's another
way for a server to ask a git client to fetch arbitrary
content: by having an http-alternates file (or a regular
alternates file, which is used as a backup).

Similar to the HTTP redirect case, a malicious server can
claim to have refs pointing at object X, return a 404 when
the client asks for X, but point to some other URL via
http-alternates, which the client will transparently fetch.
The end result is that it looks from the user's perspective
like the objects came from the malicious server, as the
other URL is not mentioned at all.

Worse, because we feed the new URL to curl ourselves, the
usual protocol restrictions do not kick in (neither curl's
default of disallowing file://, nor the protocol
whitelisting in f4113cac0 (http: limit redirection to
protocol-whitelist, 2015-09-22).

Let's apply the same rules here as we do for HTTP redirects.
Namely:

- unless http.followRedirects is set to "always", we will
not follow remote redirects from http-alternates (or
alternates) at all

- set CURLOPT_PROTOCOLS alongside CURLOPT_REDIR_PROTOCOLS
restrict ourselves to a known-safe set and respect any
user-provided whitelist.

- mention alternate object stores on stderr so that the
user is aware another source of objects may be involved

The first item may prove to be too restrictive. The most
common use of alternates is to point to another path on the
same server. While it's possible for a single-server
redirect to be an attack, it takes a fairly obscure setup
(victim and evil repository on the same host, host speaks
dumb http, and evil repository has access to edit its own
http-alternates file).

So we could make the checks more specific, and only cover
cross-server redirects. But that means parsing the URLs
ourselves, rather than letting curl handle them. This patch
goes for the simpler approach. Given that they are only used
with dumb http, http-alternates are probably pretty rare.
And there's an escape hatch: the user can allow redirects on
a specific server by setting http.<url>.followRedirects to
"always".

Reported-by: Jann Horn <jannh@google.com>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

http: make redirects more obvious

We instruct curl to always follow HTTP redirects. This is
convenient, but it creates opportunities for malicious
servers to create confusing situations. For instance,
imagine Alice is a git user with access to a private
repository on Bob's server. Mallory runs her own server and
wants to access objects from Bob's repository.

Mallory may try a few tricks that involve asking Alice to
clone from her, build on top, and then push the result:

1. Mallory may simply redirect all fetch requests to Bob's
server. Git will transparently follow those redirects
and fetch Bob's history, which Alice may believe she
got from Mallory. The subsequent push seems like it is
just feeding Mallory back her own objects, but is
actually leaking Bob's objects. There is nothing in
git's output to indicate that Bob's repository was
involved at all.

The downside (for Mallory) of this attack is that Alice
will have received Bob's entire repository, and is
likely to notice that when building on top of it.

2. If Mallory happens to know the sha1 of some object X in
Bob's repository, she can instead build her own history
that references that object. She then runs a dumb http
server, and Alice's client will fetch each object
individually. When it asks for X, Mallory redirects her
to Bob's server. The end result is that Alice obtains
objects from Bob, but they may be buried deep in
history. Alice is less likely to notice.

Both of these attacks are fairly hard to pull off. There's a
social component in getting Mallory to convince Alice to
work with her. Alice may be prompted for credentials in
accessing Bob's repository (but not always, if she is using
a credential helper that caches). Attack (1) requires a
certain amount of obliviousness on Alice's part while making
a new commit. Attack (2) requires that Mallory knows a sha1
in Bob's repository, that Bob's server supports dumb http,
and that the object in question is loose on Bob's server.

But we can probably make things a bit more obvious without
any loss of functionality. This patch does two things to
that end.

First, when we encounter a whole-repo redirect during the
initial ref discovery, we now inform the user on stderr,
making attack (1) much more obvious.

Second, the decision to follow redirects is now
configurable. The truly paranoid can set the new
http.followRedirects to false to avoid any redirection
entirely. But for a more practical default, we will disallow
redirects only after the initial ref discovery. This is
enough to thwart attacks similar to (2), while still
allowing the common use of redirects at the repository
level. Since c93c92f30 (http: update base URLs when we see
redirects, 2013-09-28) we re-root all further requests from
the redirect destination, which should generally mean that
no further redirection is necessary.

As an escape hatch, in case there really is a server that
needs to redirect individual requests, the user can set
http.followRedirects to "true" (and this can be done on a
per-server basis via http.*.followRedirects config).

Reported-by: Jann Horn <jannh@google.com>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

remote-curl: rename shadowed options variable

The discover_refs() function has a local "options" variable
to hold the http_get_options we pass to http_get_strbuf().
But this shadows the global "struct options" that holds our
program-level options, which cannot be accessed from this
function.

Let's give the local one a more descriptive name so we can
tell the two apart.

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

http: always update the base URL for redirects

If a malicious server redirects the initial ref
advertisement, it may be able to leak sha1s from other,
unrelated servers that the client has access to. For
example, imagine that Alice is a git user, she has access to
a private repository on a server hosted by Bob, and Mallory
runs a malicious server and wants to find out about Bob's
private repository.

Mallory asks Alice to clone an unrelated repository from her
over HTTP. When Alice's client contacts Mallory's server for
the initial ref advertisement, the server issues an HTTP
redirect for Bob's server. Alice contacts Bob's server and
gets the ref advertisement for the private repository. If
there is anything to fetch, she then follows up by asking
the server for one or more sha1 objects. But who is the
server?

If it is still Mallory's server, then Alice will leak the
existence of those sha1s to her.

Since commit c93c92f30 (http: update base URLs when we see
redirects, 2013-09-28), the client usually rewrites the base
URL such that all further requests will go to Bob's server.
But this is done by textually matching the URL. If we were
originally looking for "http://mallory/repo.git/info/refs",
and we got pointed at "http://bob/other.git/info/refs", then
we know that the right root is "http://bob/other.git".

If the redirect appears to change more than just the root,
we punt and continue to use the original server. E.g.,
imagine the redirect adds a URL component that Bob's server
will ignore, like "http://bob/other.git/info/refs?dummy=1".

We can solve this by aborting in this case rather than
silently continuing to use Mallory's server. In addition to
protecting from sha1 leakage, it's arguably safer and more
sane to refuse a confusing redirect like that in general.
For example, part of the motivation in c93c92f30 is
avoiding accidentally sending credentials over clear http,
just to get a response that says "try again over https". So
even in a non-malicious case, we'd prefer to err on the side
of caution.

The downside is that it's possible this will break a
legitimate but complicated server-side redirection scheme.
The setup given in the newly added test does work, but it's
convoluted enough that we don't need to care about it. A
more plausible case would be a server which redirects a
request for "info/refs?service=git-upload-pack" to just
"info/refs" (because it does not do smart HTTP, and for some
reason really dislikes query parameters). Right now we
would transparently downgrade to dumb-http, but with this
patch, we'd complain (and the user would have to set
GIT_SMART_HTTP=0 to fetch).

Reported-by: Jann Horn <jannh@google.com>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

http: simplify update_url_from_redirect

This function looks for a common tail between what we asked
for and where we were redirected to, but it open-codes the
comparison. We can avoid some confusing subtractions by
using strip_suffix_mem().

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