reflog: add for_each_reflog_ent_reverse() API

"git checkout -" is a short-hand for "git checkout @{-1}" and the
"@{nth}" notation for a negative number is to find nth previous
checkout in the reflog of the HEAD to determine the name of the
branch the user was on.  We would want to find the nth most recent
reflog entry that matches "checkout: moving from X to Y" for this.

Unfortunately, reflog is implemented as an append-only file, and the
API to iterate over its entries, for_each_reflog_ent(), reads the
file in order, giving the entries from the oldest to newer.  For the
purpose of finding nth most recent one, this API forces us to record
the last n entries in a rotating buffer and give the result out only
after we read everything.  To optimize for a common case of finding
the nth most recent one for a small value of n, we also have a side
API for_each_recent_reflog_ent() that starts reading near the end of
the file, but it still has to read the entries in the "wrong" order.
The implementation of understanding @{-1} uses this interface.

This all becomes unnecessary if we add an API to let us iterate over
reflog entries in the reverse order, from the newest to older.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
environment: add GIT_PREFIX to local_repo_env

The GIT_PREFIX variable is set based on our location within
the working tree. It should therefore be cleared whenever
GIT_WORK_TREE is cleared.

In practice, this doesn't cause any bugs, because none of
the sub-programs we invoke with local_repo_env cleared
actually care about GIT_PREFIX. But this is the right thing
to do, and future proofs us against that assumption changing.

While we're at it, let's define a GIT_PREFIX_ENVIRONMENT
macro; this avoids repetition of the string literal, which
can help catch any spelling mistakes in the code.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
setup: suppress implicit "." work-tree for bare repos

If an explicit GIT_DIR is given without a working tree, we
implicitly assume that the current working directory should
be used as the working tree. E.g.,:

  GIT_DIR=/some/repo.git git status

would compare against the cwd.

Unfortunately, we fool this rule for sub-invocations of git
by setting GIT_DIR internally ourselves. For example:

  git init foo
  cd foo/.git
  git status ;# fails, as we expect
  git config alias.st status
  git status ;# does not fail, but should

What happens is that we run setup_git_directory when doing
alias lookup (since we need to see the config), set GIT_DIR
as a result, and then leave GIT_WORK_TREE blank (because we
do not have one). Then when we actually run the status
command, we do setup_git_directory again, which sees our
explicit GIT_DIR and uses the cwd as an implicit worktree.

It's tempting to argue that we should be suppressing that
second invocation of setup_git_directory, as it could use
the values we already found in memory. However, the problem
still exists for sub-processes (e.g., if "git status" were
an external command).

You can see another example with the "--bare" option, which
sets GIT_DIR explicitly. For example:

  git init foo
  cd foo/.git
  git status ;# fails
  git --bare status ;# does NOT fail

We need some way of telling sub-processes "even though
GIT_DIR is set, do not use cwd as an implicit working tree".
We could do it by putting a special token into
GIT_WORK_TREE, but the obvious choice (an empty string) has
some portability problems.

Instead, we add a new boolean variable, GIT_IMPLICIT_WORK_TREE,
which suppresses the use of cwd as a working tree when
GIT_DIR is set. We trigger the new variable when we know we
are in a bare setting.

The variable is left intentionally undocumented, as this is
an internal detail (for now, anyway). If somebody comes up
with a good alternate use for it, and once we are confident
we have shaken any bugs out of it, we can consider promoting
it further.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Update draft release notes to 1.8.2

Split the backward-compatibility notes into two sections, the ones
that affect this release, and the other to describe changes meant
for Git 2.0.  The latter gives a context to understand why the
changes for this release is necessary.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
Merge git://git.bogomips.org/git-svn

* git://git.bogomips.org/git-svn:
  git svn: consistent spacing after "W:" in warnings
  git svn: ignore partial svn:mergeinfo
builtin/add.c: simplify boolean variables

Do not to explicitly initialize static variables to 0 and instead
let BSS take care of it.  Also use OPT_BOOL() to let the command
line arguments set these variables to 0 or 1, instead of the
deprecated OPT_BOOLEAN() aka OPT_COUNTUP().

Signed-off-by: Junio C Hamano <gitster@pobox.com>
git add: start preparing for "git add <pathspec>..." to default to "-A"

When "git add subdir/" is run without "-u" or "-A" option, e.g.

    $ edit subdir/x
    $ create subdir/y
    $ rm subdir/z
    $ git add subdir/

the command does not notice removal of paths (e.g. subdir/z) from
the working tree.  This sometimes confuses new people, as arguably
"git add" is told to record the current state of "subdir/" as a
whole, not the current state of the paths that exist in the working
tree that matches that pathspec (the latter by definition excludes
the state of "subdir/z" because it does not exist in the working
tree).

Plan to eventually make "git add" pretend as if "-A" is given when
there is a pathspec on the command line.  When resolving a conflict
to remove a path, the current code tells you to "git rm $path", but
with such a change, you will be able to say "git add $path" (of
course you can do "git add -A $path" today).  That means that we can
simplify the advice messages given by "git status".  That all will
be in Git 2.0 or later, if we are going to do so.

For that transition to work, people need to learn either to say "git
add --no-all subdir/" when they want to ignore the removed paths
like "subdir/z", or to say "git add -A subdir/" when they want to
take the state of the directory as a whole.

"git add" without any argument will continue to be a no-op.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
format-patch: RFC 2047 says multi-octet character may not be split

Even though an earlier attempt (bafc478..41dd00bad) cleaned
up RFC 2047 encoding, pretty.c::add_rfc2047() still decides
where to split the output line by going through the input
one byte at a time, and potentially splits a character in
the middle.  A subject line may end up showing like this:

     ".... fö?? bar".   (instead of  ".... föö bar".)

if split incorrectly.

RFC 2047, section 5 (3) explicitly forbids such beaviour

    Each 'encoded-word' MUST represent an integral number of
    characters.  A multi-octet character may not be split across
    adjacent 'encoded- word's.

that means that e.g. for

    Subject: .... föö bar

encoding

    Subject: =?UTF-8?q?....=20f=C3=B6=C3=B6?=
     =?UTF-8?q?=20bar?=

is correct, and

    Subject: =?UTF-8?q?....=20f=C3=B6=C3?=      <-- NOTE ö is broken here
     =?UTF-8?q?=B6=20bar?=

is not, because "ö" character UTF-8 encoding C3 B6 is split here across
adjacent encoded words.

To fix the problem, make the loop grab one _character_ at a time and
determine its output length to see where to break the output line.  Note
that this version only knows about UTF-8, but the logic to grab one
character is abstracted out in mbs_chrlen() function to make it possible
to extend it to other encodings with the help of iconv in the future.

Signed-off-by: Kirill Smelkov <kirr@mns.spb.ru>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
perf: update documentation of GIT_PERF_REPEAT_COUNT

Currently the documentation of GIT_PERF_REPEAT_COUNT says the default is
five while "perf-lib.sh" uses a value of three as a default.

Update the documentation so that it is consistent with the code.

Signed-off-by: Antoine Pelisse <apelisse@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Merge branch 'maint'

* maint:
  perf: update documentation of GIT_PERF_REPEAT_COUNT
shell doc: emphasize purpose and security model

The original git-shell(1) manpage emphasized that the shell supports
only git transport commands.  As the shell gained features, that
emphasis and focus in the manual has been lost.  Bring it back by
splitting the manpage into a few short sections and fleshing out each:

 - SYNOPSIS, describing how the shell gets used in practice
 - DESCRIPTION, which gives an overview of the purpose and guarantees
   provided by this restricted shell
 - COMMANDS, listing supported commands and restrictions on the
   arguments they accept
 - INTERACTIVE USE, describing the interactive mode

Also add a "see also" section with related reading.

Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
shell: new no-interactive-login command to print a custom message

If I disable git-shell's interactive mode by removing the
~/git-shell-commands directory, attempts to ssh in to the service
produce a message intended for the administrator:

	$ ssh git@myserver
	fatal: Interactive git shell is not enabled.
	hint: ~/git-shell-commands should exist and have read and execute access.
	$

That is helpful for the new admin who is wondering "What? Why isn't
the git-shell I just set up working?", but once the site setup is
complete, it would be better to give the user a friendly hint that she
is on the right track, like GitHub does.

	Hi <username>! You've successfully authenticated, but
	GitHub does not provide shell access.

An appropriate greeting might even include more complex dynamic
information, like gitolite's list of repositories the user has access
to.  Add support for a ~/git-shell-commands/no-interactive-login
command that generates an arbitrary greeting.  When the user tries to
log in:

 * If the file ~/git-shell-commands/no-interactive-login exists,
   run no-interactive-login to let the server say what it likes,
   then hang up.

 * Otherwise, if ~/git-shell-commands/ is present, start an
   interactive read-eval-print loop.

 * Otherwise, print the usual configuration hint and hang up.

Reported-by: Ethan Reesor <firelizzard@gmail.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Improved-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Translate git_more_info_string consistently

"git help" translated the "See 'git help <command>' for more
information..." message, but "git" didn't.

Signed-off-by: Kevin Bracey <kevin@bracey.fi>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
test-lib: factor out $GIT_UNZIP setup

We set up the $GIT_UNZIP variable and lazy prereq in
multiple places (and the next patch is about to add another
one). Let's factor it out to avoid repeating ourselves.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
archive: handle commits with an empty tree

git-archive relies on get_pathspec to convert its argv into
a list of pathspecs. When get_pathspec is given an empty
argv list, it returns a single pathspec, the empty string,
to indicate that everything matches. When we feed this to
our path_exists function, we typically see that the pathspec
turns up at least one item in the tree, and we are happy.

But when our tree is empty, we erroneously think it is
because the pathspec is too limited, when in fact it is
simply that there is nothing to be found in the tree. This
is a weird corner case, but the correct behavior is almost
certainly to produce an empty archive, not to exit with an
error.

This patch teaches git-archive to create empty archives when
there is no pathspec given (we continue to complain if a
pathspec is given, since it obviously is not matched). It
also confirms that the tar and zip writers produce sane
output in this instance.

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

* maint:
  Translate git_more_info_string consistently
add: update pathless 'add [-u|-A]' warning to reflect change of plan

We originally thought the transition would need a period where "git add
[-u|-A]" without pathspec would be forbidden, but the warning is big
enough to scare people and teach them not to use it (or, if so, to
understand the consequences).

Signed-off-by: Matthieu Moy <Matthieu.Moy@imag.fr>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Merge branch 'gp/add-u-A-documentation'

* gp/add-u-A-documentation:
  add: Clarify documentation of -A and -u
git-completion.bash: zsh does not implement function redirection correctly

A recent change added functions whose entire standard error stream
is redirected to /dev/null using a construct that is valid POSIX.1
but is not widely used:

	funcname () {
		cd "$1" && run some command "$2"
	} 2>/dev/null

Even though this file is "git-completion.bash", zsh completion
support dot-sources it (instead of asking bash to grok it like tcsh
completion does), and zsh does not implement this redirection
correctly.

With zsh, trying to complete an inexistant directory gave this:

  git add no-such-dir/__git_ls_files_helper:cd:2: no such file or directory: no-such-dir/

Also these functions use "cd" to first go somewhere else before
running a command, but the location the caller wants them to go that
is given as an argument to them should not be affected by CDPATH
variable the users may have set for their interactive session.

To fix both of these, wrap the body of the function in a subshell,
unset CDPATH at the beginning of the subshell, and redirect the
standard error stream of the subshell to /dev/null.

Signed-off-by: Matthieu Moy <Matthieu.Moy@imag.fr>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Merge branch 'mm/add-u-A-finishing-touches'

* mm/add-u-A-finishing-touches:
  add: update pathless 'add [-u|-A]' warning to reflect change of plan