apply --ignore-space-change: lines with and without leading whitespaces do not match

The fuzzy_matchlines() function is used when attempting to resurrect
a patch that is whitespace-damaged, or when applying a patch that
was produced against an old codebase to the codebase after
indentation change.

The patch may want to change a line "a_bc" ("_" is used throught
this description for a whitespace to make it stand out) in the
original into something else, and we may not find "a_bc" in the
current source, but there may be "a__bc" (two spaces instead of one
the whitespace-damaged patch claims to expect).  By ignoring the
amount of whitespaces, it forces "git apply" to consider that "a_bc"
in the broken patch meant to refer to "a__bc" in reality.

However, the implementation special cases a run of whitespaces at
the beginning of a line and makes "abc" match "_abc", even though a
whitespace in the middle of string never matches a 0-width gap,
e.g. "a_bc" does not match "abc".  A run of whitespace at the end of
one string does not match a 0-width end of line on the other line,
either, e.g. "abc_" does not match "abc".

Fix this inconsistency by making the code skip leading whitespaces
only when both strings begin with a whitespace.  This makes the
option mean the same as the option of the same name in "diff" and
"git diff".

Note that I am not sure if anybody sane should use this option in
the first place.  The fuzzy match logic may be able to find the
original line that the patch author may have meant to touch because
it does not fully trust what the original lines say (i.e. context
lines prefixed by " " and old lines prefixed by "-" does not have to
exactly match the contents the patch is applied to).  There is no
reason for us to trust what the replacement lines (i.e. new lines
prefixed by "+") say, either, but with this option enabled, we end
up copying these new lines with suspicious whitespace distributions
literally into the patched result.  But as long as we keep it, we
should make it do its insane thing consistently.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
Portable alloca for Git

In the next patch we'll have to use alloca() for performance reasons,
but since alloca is non-standardized and is not portable, let's have a
trick with compatibility wrappers:

1. at configure time, determine, do we have working alloca() through
   alloca.h, and define

    #define HAVE_ALLOCA_H

   if yes.

2. in code

    #ifdef HAVE_ALLOCA_H
    # include <alloca.h>
    # define xalloca(size)      (alloca(size))
    # define xalloca_free(p)    do {} while(0)
    #else
    # define xalloca(size)      (xmalloc(size))
    # define xalloca_free(p)    (free(p))
    #endif

   and use it like

   func() {
       p = xalloca(size);
       ...

       xalloca_free(p);
   }

This way, for systems, where alloca is available, we'll have optimal
on-stack allocations with fast executions. On the other hand, on
systems, where alloca is not available, this gracefully fallbacks to
xmalloc/free.

Both autoconf and config.mak.uname configurations were updated. For
autoconf, we are not bothering considering cases, when no alloca.h is
available, but alloca() works some other way - its simply alloca.h is
available and works or not, everything else is deep legacy.

For config.mak.uname, I've tried to make my almost-sure guess for where
alloca() is available, but since I only have access to Linux it is the
only change I can be sure about myself, with relevant to other changed
systems people Cc'ed.

NOTE

SunOS and Windows had explicit -DHAVE_ALLOCA_H in their configurations.
I've changed that to now-common HAVE_ALLOCA_H=YesPlease which should be
correct.

Cc: Brandon Casey <drafnel@gmail.com>
Cc: Marius Storm-Olsen <mstormo@gmail.com>
Cc: Johannes Sixt <j6t@kdbg.org>
Cc: Johannes Schindelin <Johannes.Schindelin@gmx.de>
Cc: Ramsay Jones <ramsay@ramsay1.demon.co.uk>
Cc: Gerrit Pape <pape@smarden.org>
Cc: Petr Salinger <Petr.Salinger@seznam.cz>
Cc: Jonathan Nieder <jrnieder@gmail.com>
Acked-by: Thomas Schwinge <thomas@codesourcery.com> (GNU Hurd changes)
Signed-off-by: Kirill Smelkov <kirr@mns.spb.ru>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
MSVC: fix t0040-parse-options crash

On 64-bit MSVC, pointers are 64 bit but `long` is only 32.
Thus, casting string to `unsigned long`, which is redundand on other
platforms, throws away important bits and when later cast to `intptr_t`
results in corrupt pointer.

This patch fixes test-parse-options by replacing harming cast with
correct one.

Signed-off-by: Marat Radchenko <marat@slonopotamus.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
parse-options: add cast to correct pointer type to OPT_SET_PTR

Do not force users of OPT_SET_PTR to cast pointer to correct
underlying pointer type by integrating cast into OPT_SET_PTR macro.

Cast is required to prevent 'initialization makes integer from pointer
without a cast' compiler warning.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
patch-id: make it stable against hunk reordering

Patch id changes if users
1. reorder file diffs that make up a patch
or
2. split a patch up to multiple diffs that touch the same path
(keeping hunks within a single diff ordered to make patch valid).

As the result is functionally equivalent, a different patch id is
surprising to many users.
In particular, reordering files using diff -O is helpful to make patches
more readable (e.g. API header diff before implementation diff).

Change patch-id behaviour making it stable against these two kinds
of patch change:
1. calculate SHA1 hash for each hunk separately and sum all hashes
(using a symmetrical sum) to get patch id
2. hash the file-level headers together with each hunk (not just the
first hunk)

We use a 20byte sum and not xor - since xor would give 0 output
for patches that have two identical diffs, which isn't all that
unlikely (e.g. append the same line in two places).

Add a new flag --unstable to get the historical behaviour.

Add --stable which is a nop, for symmetry.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
patch-id: document new behaviour

Clarify that patch ID is now a sum of hashes, not a hash.
Document --stable and --unstable flags.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
patch-id-test: test --stable and --unstable flags

Verify that patch ID is now stable against diff split and reordering.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
parse-options: remove unused OPT_SET_PTR

OPT_SET_PTR was never used since its creation at db7244bd
(parse-options new features., 2007-11-07).

Signed-off-by: Junio C Hamano <gitster@pobox.com>
Documentation: fix misuses of "nor"

Signed-off-by: Justin Lebar <jlebar@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
contrib: fix misuses of "nor"

Signed-off-by: Justin Lebar <jlebar@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
comments: fix misuses of "nor"

Signed-off-by: Justin Lebar <jlebar@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
code and test: fix misuses of "nor"

Signed-off-by: Justin Lebar <jlebar@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Revert "Merge branch 'wt/doc-submodule-name-path-confusion-2'"

This reverts commit 00d4ff1a69883e24b095f45251d99143b5bc0320, reversing
changes made to d3badc6eb0961382788c2670129d5ee133d079fd.
date: recognize bogus FreeBSD gmtime output

Most gmtime implementations return a NULL value when they
encounter an error (and this behavior is specified by ANSI C
and POSIX).  FreeBSD's implementation, however, will simply
leave the "struct tm" untouched.  Let's also recognize this
and convert it to a NULL (with this patch, t4212 should pass
on FreeBSD).

Reported-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
t4212: loosen far-in-future test for AIX

One of the tests in t4212 checks our behavior when we feed
gmtime a date so far in the future that it gives up and
returns NULL. Some implementations, like AIX, may actually
just provide us a bogus result instead.

It's not worth it for us to come up with heuristics that
guess whether the return value is sensible or not. On good
platforms where gmtime reports the problem to us with NULL,
we will print the epoch value. On bad platforms, we will
print garbage.  But our test should be written for the
lowest common denominator so that it passes everywhere.

Reported-by: Charles Bailey <cbailey32@bloomberg.net>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
update-ref: fail create operation over stdin if ref already exists

Signed-off-by: Aman Gupta <aman@tmm1.net>
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Acked-by: Brad King <brad.king@kitware.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Revert "submodule: explicit local branch creation in module_clone"

This reverts commit 23d25e48f5ead73c9ce233986f90791abec9f1e8, as it is
broken for users who haven't opted into the new feature of checking
out submodule.*.branch with update mode set to checkout.
Revert part of 384364b (Start preparing for Git 2.0, 2014-03-07)

As we are not shipping with the submodule change, remove the
entry for it.
Merge branch 'rs/pickaxe-i'

Allow the options -i/--regexp-ignore-case, --pickaxe-regex, and -S
to be used together and work as expected to perform a pickaxe
search using case-insensitive regular expression matching.

* rs/pickaxe-i:
  pickaxe: simplify kwset loop in contains()
  pickaxe: call strlen only when necessary in diffcore_pickaxe_count()
  pickaxe: move pickaxe() after pickaxe_match()
  pickaxe: merge diffcore_pickaxe_grep() and diffcore_pickaxe_count() into diffcore_pickaxe()
  pickaxe: honor -i when used with -S and --pickaxe-regex
  t4209: use helper functions to test --author
  t4209: use helper functions to test --grep
  t4209: factor out helper function test_log_icase()
  t4209: factor out helper function test_log()
  t4209: set up expectations up front
Merge branch 'ap/remote-hg-skip-null-bookmarks'

* ap/remote-hg-skip-null-bookmarks:
  remote-hg: do not fail on invalid bookmarks