glossary-content.txt: rephrase magic signature part

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Support pathspec magic :(exclude) and its short form :!

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
pathspec.c: support adding prefix magic to a pathspec with mnemonic magic

Back in 233c3e6 (parse_pathspec: preserve prefix length via
PATHSPEC_PREFIX_ORIGIN - 2013-07-14), parse_pathspec() is taught to
save prefix length as a dynamic magic. This is needed when the
pathspec is passed to another process and and prefix lenght would be
lost.

Back then we support two cases. If the pathspec is normal, e.g. "abc",
we simply add the prefix to become ":(prefix:2)abc". If the pathspec
contains long magic, e.g. ":(foo,bar)abc" then we turn it to
":(foo,bar,prefix:2)abc". We do not support prefixing on short form,
because the only supported mnemonic '/' disappears after the the
preprocessing steps.

With the introduction of exclude magic with mnemonic '!', we need to
add support for the short form case so that ':!abc' becomes
':(exclude,prefix:2)abc'. Without this, it will break

    cd Documentation
    git add -p -- . ':!technical'

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
rename READ_SHA1_FILE_REPLACE flag to LOOKUP_REPLACE_OBJECT

The READ_SHA1_FILE_REPLACE flag is more related to using the
lookup_replace_object() function rather than the
read_sha1_file() function.

We also need such a flag to be used with sha1_object_info()
instead of read_sha1_file().

The name LOOKUP_REPLACE_OBJECT is therefore better for this
flag.

Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
replace_object: don't check read_replace_refs twice

Since e1111cef (inline lookup_replace_object() calls,
May 15 2011) the read_replace_refs global variable is
checked twice, once in lookup_replace_object() and
once again in do_lookup_replace_object().

As do_lookup_replace_object() is called only from
lookup_replace_object(), we can remove the check in
do_lookup_replace_object().

Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
sha1_file.c: add lookup_replace_object_extended() to pass flags

Currently, there is only one caller to lookup_replace_object()
that can benefit from passing it some flags, but we expect
that there could be more.

Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
sha1_object_info_extended(): add an "unsigned flags" parameter

This parameter is not used yet, but it will be used to tell
sha1_object_info_extended() if it should perform object
replacement or not.

Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
t6050: show that git cat-file --batch fails with replace objects

When --batch is passed to git cat-file, the sha1_object_info_extended()
function is used to get information about the objects passed to
git cat-file.

Unfortunately sha1_object_info_extended() doesn't take care of
object replacement properly, so it will often fail with a
message like this:

$ echo a3fb2e1845a1aaf129b7975048973414dc172173 | git cat-file --batch
a3fb2e1845a1aaf129b7975048973414dc172173 commit 231
fatal: object a3fb2e1845a1aaf129b7975048973414dc172173 change size!?

The goal of this patch is to show this breakage.

Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
sha1_file: perform object replacement in sha1_object_info_extended()

sha1_object_info_extended() should perform object replacement
if it is needed.

The simplest way to do that is to make it call
lookup_replace_object_extended().

And now its "unsigned flags" parameter is used as it is passed
to lookup_replace_object_extended().

Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
builtin/replace: teach listing using short, medium or full formats

By default when listing replace refs, only the sha1 of the
replaced objects are shown.

In many cases, it is much nicer to be able to list all the
sha1 of the replaced objects along with the sha1 of the
replacment objects.

And in other cases it might be interesting to also show the
types of the replaced and replacement objects.

This patch introduce a new --format=<fmt> option where
<fmt> can be any of the following:

	'short': this is the same as when no --format
		option is used, that is only the sha1 of
		the replaced objects are shown
	'medium': this also lists the sha1 of the
		replacement objects
	'full': this shows the sha1 and the type of both
		the replaced and the replacement objects

Some documentation and some tests will follow.

Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
t6050: add tests for listing with --format

This patch adds tests for "git replace -l --format=<fmt>".

'short', 'medium' and 'full' are the only allowed values
for <fmt>.

'short' is the same as with no --format option.
Tests for 'medium' and 'full' are the most needed.

Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
builtin/replace: unset read_replace_refs

When checking to see if some objects are of the same type
and when displaying the type of objects, git replace uses
the sha1_object_info() function.

Unfortunately this function by default respects replace
refs, so instead of the type of a replaced object, it
gives the type of the replacement object which might
be different.

To fix this bug, and because git replace should work at a
level before replacement takes place, let's unset the
read_replace_refs global variable at the beginning of
cmd_replace().

Suggested-by: Jeff King <peff@peff.net>
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Documentation/git-replace: describe --format option

Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Prevent buffer overflows when path is too long

Some buffers created with PATH_MAX length are not checked when being
written, and can overflow if PATH_MAX is not big enough to hold the
path.

Replace those buffers by strbufs so that their size is automatically
grown if necessary. They are created as static local variables to avoid
reallocating memory on each call. Note that prefix_filename() returns
this static buffer so each callers should copy or use the string
immediately (this is currently true).

Reported-by: Wataru Noguchi <wnoguchi.0727@gmail.com>
Signed-off-by: Antoine Pelisse <apelisse@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
prune-packed: use strbuf to avoid having to worry about PATH_MAX

A/very/long/path/to/.git that becomes exactly PATH_MAX bytes long
after suffixed with /objects/??/??38-hex??, would have overflown
the on-stack pathname[] buffer.

Noticed-by:  Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
docs: add filter-branch notes on The BFG

The BFG is a tool specifically designed for the task of removing
unwanted data from Git repository history - a common use-case for which
git-filter-branch has been the traditional workhorse.

It's beneficial to let users know that filter-branch has an alternative
here:

* speed : The BFG is 10-50x faster
  http://rtyley.github.io/bfg-repo-cleaner/#speed
* complexity of configuration : filter-branch is a very flexible tool,
  but demands very careful usage in order to get the desired results
  http://rtyley.github.io/bfg-repo-cleaner/#examples

Obviously, filter-branch has it's advantages too - it permits very
complex rewrites, and doesn't require a JVM - but for the common
use-case of deleting unwanted data, it's helpful to users to be aware
that an alternative exists.

The BFG was released under the GPL in February 2013, and has since seen
widespread production use (The Guardian, RedHat, Google, UK Government
Digital Service), been tested against large repos (~300K commits, ~5GB
packfiles) and received significant positive feedback from users:

http://rtyley.github.io/bfg-repo-cleaner/#feedback

Signed-off-by: Roberto Tyley <roberto.tyley@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
get_max_fd_limit(): fall back to OPEN_MAX upon getrlimit/sysconf failure

On broken systems where RLIMIT_NOFILE is visible by the compliers
but underlying getrlimit() system call does not behave, we used to
simply die() when we are trying to decide how many file descriptors
to allocate for keeping packfiles open.  Instead, allow the fallback
codepath to take over when we get such a failure from getrlimit().

The same issue exists with _SC_OPEN_MAX and sysconf(); restructure
the code in a similar way to prepare for a broken sysconf() as well.

Noticed-by: Joey Hess <joey@kitenet.net>
Helped-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
builtin/prune.c: use strbuf to avoid having to worry about PATH_MAX

While at it, rename prune_tmp_object(), which used to be a helper to
remove temporary files that were created to become loose object
files, to prune_tmp_file(), as the function is also used to remove
any random cruft whose name begins with tmp_ directly in .git/object
or .git/object/pack directories these days.

Noticed-by:  Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
t4056: add new tests for "git diff -O"

Adapted from $gmane/236427 by Anders Waldenborg, "diff: Add
diff.orderfile configuration variable".

Signed-off-by: Anders Waldenborg <anders@0x63.nu>
Signed-off-by: Samuel Bronson <naesten@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff: let "git diff -O" read orderfile from any file and fail properly

The -O flag really shouldn't silently fail to do anything when given
a path that it can't read from.

However, it should be able to read from un-mmappable files, such as:

 * pipes/fifos

 * /dev/null:  It's a character device (at least on Linux)

 * ANY empty file:

   Quoting Linux mmap(2), "SUSv3 specifies that mmap() should fail if
   length is 0.  However, in kernels before 2.6.12, mmap() succeeded in
   this case: no mapping was created and the call returned addr.  Since
   kernel 2.6.12, mmap() fails with the error EINVAL for this case."

We especially want "-O/dev/null" to work, since we will be documenting
it as the way to cancel "diff.orderfile" when we add that.

(Note: "-O/dev/null" did have the right effect, since the existing error
handling essentially worked out to "silently ignore the orderfile".  But
this was probably more coincidence than anything else.)

So, lets toss all of that logic to get the file mmapped and just use
strbuf_read_file() instead, which gives us decent error handling
practically for free.

Signed-off-by: Samuel Bronson <naesten@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>