diff: remove "diff-files -q" in a version of Git in a distant future

This was inherited from "show-diff -q" that was invented to tell
comparison between the index and the working tree to ignore only
removals in 2005.

These days, it is spelled as "--diff-filter=d".

Signed-off-by: Junio C Hamano <gitster@pobox.com>
merge-base: use OPT_CMDMODE and clarify the command line parsing

The --octopus, --independent and --is-ancestor are mutually
exclusive command modes (in addition to not giving any of these
options), so represent them as such using the recent OPT_CMDMODE
facility available since 11588263 (parse-options: add OPT_CMDMODE(),
2013-07-30), which is in v1.8.4-82-g366b80b.  --all is compatible
only with plain vanilla mode and --octopus mode, and the minimum
number of arguments the command takes depends on the command modes,
so these are now separately checked in each command mode.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
log_tree_diff: die when we fail to parse a commit

We currently call parse_commit and then assume we can
dereference the resulting "tree" struct field. If parsing
failed, however, that field is NULL and we end up
segfaulting.

Instead of a segfault, let's print an error message and die
a little more gracefully.

Note that this should never happen in practice, but may
happen in a corrupt repository.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
assume parse_commit checks commit->object.parsed

The parse_commit function will check the "parsed" flag of
the object and do nothing if it is set. There is no need
for callers to check the flag themselves, and doing so only
clutters the code.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
assume parse_commit checks for NULL commit

The parse_commit function will check whether it was passed a
NULL commit pointer, and if so, return an error. There is no
need for callers to check this separately.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
use parse_commit_or_die instead of segfaulting

Some unchecked calls to parse_commit should obviously die on
error, because their next step is to start looking at the
parsed fields, which will cause a segfault. These are
obvious candidates for parse_commit_or_die, which will be a
strict improvement in behavior.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
use parse_commit_or_die instead of custom message

Many calls to parse_commit detect errors and die. In some
cases, the custom error messages are more useful than what
parse_commit_or_die could produce, because they give some
context, like which ref the commit came from. Some, however,
just say "invalid commit". Let's convert the latter to use
parse_commit_or_die; its message is slightly more informative,
and it makes the error more consistent throughout git.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
checkout: do not die when leaving broken detached HEAD

If we move away from a detached HEAD that has broken or
corrupted commits, we might die in two places:

  1. Printing the "old HEAD was..." message.

  2. Printing the list of orphaned commits.

In both cases, we ignore the return value of parse_commit
and feed the resulting commit to the pretty-print machinery,
which will die() upon failing to read the commit object
itself.

Since both cases are ancillary to the real operation being
performed, let's be more robust and keep going. This lets
users more easily checkout away from broken history.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
reflog: handle lightweight and annotated tags equally

When 'git reflog <tag>' is called on a lightweight tag, nothing is
output. However, when called on an annotated tag, shortened SHA-1s for
all reachable commits are written on a single line.

Teach add_pending_object_with_mode() to handle OBJ_TAG, so that 'git
reflog' on an annotated tag is quiet, like it is for lightweight tags,
commits and blobs.

Signed-off-by: Torstein Hegge <hegge@resisty.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Change sed i\ usage to something Solaris' sed can handle

Solaris' sed was choking on the i\ commands used in
t4015-diff-whitespace as it couldn't parse the program properly.
Modify two uses of sed that worked in GNU sed but not Solaris'
(/usr/bin or /usr/xpg4/bin) to an equivalent form that is handled
properly by both.

Signed-off-by: Ben Walton <bdwalton@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
sha1_file.c:create_tmpfile(): Fix race when creating loose object dirs

There are cases (e.g. when running concurrent fetches in a repo) where
multiple Git processes concurrently attempt to create loose objects
within the same objects/XX/ dir. The creation of the loose object files
is (AFAICS) safe from races, but the creation of the objects/XX/ dir in
which the loose objects reside is unsafe, for example:

Two concurrent fetches - A and B. As part of its fetch, A needs to store
12aaaaa as a loose object. B, on the other hand, needs to store 12bbbbb
as a loose object. The objects/12 directory does not already exist.
Concurrently, both A and B determine that they need to create the
objects/12 directory (because their first call to git_mkstemp_mode()
within create_tmpfile() fails witn ENOENT). One of them - let's say A -
executes the following mkdir() call before the other. This first call
returns success, and A moves on. When B gets around to calling mkdir(),
it fails with EEXIST, because A won the race. The mkdir() error causes B
to return -1 from create_tmpfile(), which propagates all the way,
resulting in the fetch failing with:

  error: unable to create temporary file: File exists
  fatal: failed to write object
  fatal: unpack-objects failed

Although it's hard to add a testcase reproducing this issue, it's easy
to provoke if we insert a sleep after the

  if (mkdir(buffer, 0777) || adjust_shared_perm(buffer))
      return -1;

block, and then run two concurrent "git fetch"es against the same repo.

The fix is to simply handle mkdir() failing with EEXIST as a success.
If EEXIST is somehow returned for the wrong reasons (because the relevant
objects/XX is not a directory, or is otherwise unsuitable for object
storage), the following call to adjust_shared_perm(), or ultimately the
retried call to git_mkstemp_mode() will fail, and we end up returning
error from create_tmpfile() in any case.

Note that there are still cases where two users with unsuitable umasks
in a shared repo can end up in two races where one user first wins the
mkdir() race to create an objects/XX/ directory, and then the other user
wins the adjust_shared_perms() race to chmod() that directory, but fails
because it is (transiently, until the first users completes its chmod())
unwriteable to the other user. However, (an equivalent of) this race also
exists before this patch, and is made no worse by this patch.

Signed-off-by: Johan Herland <johan@herland.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
pathspec: stop --*-pathspecs impact on internal parse_pathspec() uses

Normally parse_pathspec() is used on command line arguments where it
can do fancy thing like parsing magic on each argument or adding magic
for all pathspecs based on --*-pathspecs options.

There's another use of parse_pathspec(), where pathspec is needed, but
the input is known to be pure paths. In this case we usually don't
want --*-pathspecs to interfere. And we definitely do not want to
parse magic in these paths, regardless of --literal-pathspecs.

Add new flag PATHSPEC_LITERAL_PATH for this purpose. When it's set,
--*-pathspecs are ignored, no magic is parsed. And if the caller
allows PATHSPEC_LITERAL (i.e. the next calls can take literal magic),
then PATHSPEC_LITERAL will be set.

This fixes cases where git chokes when GIT_*_PATHSPECS are set because
parse_pathspec() indicates it won't take any magic. But
GIT_*_PATHSPECS add them anyway. These are

   export GIT_LITERAL_PATHSPECS=1
   git blame -- something
   git log --follow something
   git log --merge

"git ls-files --with-tree=path" (aka parse_pathspec() in
overlay_tree_on_cache()) is safe because the input is empty, and
producing one pathspec due to PATHSPEC_PREFER_CWD does not take any
magic into account.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Acked-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
t/README: tests can use perl even with NO_PERL

The git build system supports a NO_PERL switch to avoid installing
perl bindings or other features (like "git add --patch") that rely on
perl on runtime, but even with NO_PERL it has not been possible for a
long time to run tests without perl.  Helpers such as

	nul_to_q () {
		"$PERL_PATH" -pe 'y/\000/Q/'
	}

use perl as a better tr or sed and are regularly used in tests without
worrying to add a PERL prerequisite.

Perl is portable enough that it seems fine to keep relying on it for
this kind of thing in tests (and more readable than the alternative of
trying to find POSIXy equivalents).  Update the test documentation to
clarify this.

Reported-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
doc/howto: warn about (dumb)http server document being too old

Describe when it is still applicable, and tell people where to go
for most normal cases.

Signed-off-by: Sitaram Chamarty <sitaram@atc.tcs.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
use @@PERL@@ in built scripts

Several of the built shell commands invoke a bare "perl" to
perform some one-liners. This will use the first perl in the
PATH rather than the one specified by the user's SHELL_PATH.
We are not asking these perl invocations to do anything
exotic, so typically any old system perl will do; however,
in some cases the system perl may have unexpected behavior
(e.g., by handling line endings differently). We should err
on the side of using the perl the user pointed us to.

The downside of this is that on systems with a sane perl
setup, we no longer find the perl at runtime, but instead
point to a static perl (like /usr/bin/perl). That means we
will not handle somebody moving perl without rebuilding git,
whereas before we tracked it just fine. This is probably not
a big deal, though, as the built perl scripts already
suffered from this.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
t: provide a perl() function which uses $PERL_PATH

Once upon a time, we assumed that calling a bare "perl" in
the test scripts was OK, because we would find the perl from
the user's PATH, and we were only asking that perl to do
basic operations that work even on old versions of perl.

Later, we found that some systems really prefer to use
$PERL_PATH even for these basic cases, because the system
perl misbehaves in some way (e.g., by handling line endings
differently). We then switched "perl" invocations to
"$PERL_PATH" to respect the user's choice.

Having to use "$PERL_PATH" is ugly and cumbersome, though.
Instead, let's provide a perl() shell function that tests
can use, which will transparently do the right thing.

Unfortunately, test writers still have to use $PERL_PATH in
certain situations, so we still need to keep the advice in
the README.

Note that this may fix test failures in t5004, t5503, t6002,
t6003, t6300, t8001, and t8002, depending on your system's
perl setup. All of these can be detected by running:

  ln -s /bin/false bin-wrappers/perl
  make test

which fails before this patch, and passes after.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
t: use perl instead of "$PERL_PATH" where applicable

As of the last commit, we can use "perl" instead of
"$PERL_PATH" when running tests, as the former is now a
function which uses the latter. As the shorter "perl" is
easier on the eyes, let's switch to using it everywhere.

This is not quite a mechanical s/$PERL_PATH/perl/
replacement, though. There are some places where we invoke
perl from a script we generate on the fly, and those scripts
do not have access to our internal shell functions. The
result can be double-checked by running:

  ln -s /bin/false bin-wrappers/perl
  make test

which continues to pass even after this patch.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
merge-base: teach "--fork-point" mode

The "git pull --rebase" command computes the fork point of the
branch being rebased using the reflog entries of the "base" branch
(typically a remote-tracking branch) the branch's work was based on,
in order to cope with the case in which the "base" branch has been
rewound and rebuilt.  For example, if the history looked like this:

                     o---B1
                    /
    ---o---o---B2--o---o---o---Base
            \
             B3
              \
               Derived

where the current tip of the "base" branch is at Base, but earlier
fetch observed that its tip used to be B3 and then B2 and then B1
before getting to the current commit, and the branch being rebased
on top of the latest "base" is based on commit B3, it tries to find
B3 by going through the output of "git rev-list --reflog base" (i.e.
Base, B1, B2, B3) until it finds a commit that is an ancestor of the
current tip "Derived".

Internally, we have get_merge_bases_many() that can compute this
with one-go.  We would want a merge-base between Derived and a
fictitious merge commit that would result by merging all the
historical tips of "base".  When such a commit exist, we should get
a single result, which exactly match one of the reflog entries of
"base".

Teach "git merge-base" a new mode, "--fork-point", to compute
exactly that.

Helped-by: Martin von Zweigbergk <martinvonz@gmail.com>
Helped-by: John Keeping <john@keeping.me.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
cvsserver: Determinize output to combat Perl 5.18 hash randomization

Perl 5.18 randomizes the seed used by its hash function, so iterating
through hashes results in different orders from run to run:
  http://perldoc.perl.org/perl5180delta.html#Hash-overhaul

This usually broke t9400 (gitcvs.dbname, gitcvs.ext.dbname, when
running cmp on two .sqlite files) and t9402 (check [cvswork3] diff,
when running test_cmp on two diffs).

To fix this, hide the internal order of hashes with sort when sending
output or running database queries.

(An alternative workaround is PERL_HASH_SEED=0, but this seems nicer.)

Signed-off-by: Anders Kaseorg <andersk@mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Avoid difference in tr semantics between System V and BSD

Solaris' tr (both /usr/bin/ and /usr/xpg4/bin) uses the System V
semantics for tr whereby string1's length is truncated to the length
of string2 if string2 is shorter. The BSD semantics, as used by GNU tr
see string2 padded to the length of string1 using the final character
in string2. POSIX explicitly doesn't specify the correct behavior
here, making both equally valid.

This difference means that Solaris' native tr implementations produce
different results for tr ":\t\n" "\0" than GNU tr. This breaks a few
tests in t0008-ignores.sh.

Possible fixes for this are to make string2 be "\0\0\0" or "[\0*]".

Instead, use perl to perform these transliterations which means we
don't need to worry about the difference at all. Since we're replacing
tr with perl, we also use perl to replace the sed invocations used to
transform the files.

Replace four identical transforms with a function named
broken_c_unquote. Replace the other two identical transforms with a
fuction named broken_c_unquote_verbose.

Signed-off-by: Ben Walton <bdwalton@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>