After handling options, any leftover arguments should be
commands. However, we pass through "--help" and "--version",
so that we convert them into "git help" and "git version"
respectively.

This is a straightforward use of skip_prefix to avoid a
magic number, but while we are there, it is worth adding a
comment to explain this otherwise confusing behavior.
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

There are several uses of the magic number "line+45" when
parsing ACK lines from the server, and it's rather unclear
why 45 is the correct number. We can make this more clear by
keeping a running pointer as we parse, using skip_prefix to
jump past the first "ACK ", then adding 40 to jump past
get_sha1_hex (which is still magical, but hopefully 40 is
less magical to readers of git code).

Note that this actually puts us at line+44. The original
required some character between the sha1 and further ACK
flags (it is supposed to be a space, but we never enforced
that). We start our search for flags at line+44, which
meanas we are slightly more liberal than the old code.
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

When we see a file change in a commit, we expect one of:

  1. A mark.

  2. An "inline" keyword.

  3. An object sha1.

The handling of spaces is inconsistent between the three
options. Option 1 calls a sub-function which checks for the
space, but doesn't parse past it. Option 2 parses the space,
then deliberately avoids moving the pointer past it. Option
3 detects the space locally but doesn't move past it.

This is confusing, because it looks like option 1 forgets to
check for the space (it's just buried). And option 2 checks
for "inline ", but only moves strlen("inline") characters
forward, which looks like a bug but isn't.

We can make this more clear by just having each branch move
past the space as it is checked (and we can replace the
doubled use of "inline" with a call to skip_prefix).
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

As in earlier commits, the diff option parser uses
starts_with to find that an argument starts with "--stat-",
and then adds strlen("stat-") to find the rest of the
option.

However, in this case the starts_with and the strlen are
separated across functions, making it easy to call the
latter without the former. Let's use skip_prefix instead of
raw pointer arithmetic to catch such a case.
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Like earlier cases, we can use skip_prefix to avoid magic
numbers that must match the length of starts_with prefixes.
However, the numbers are a little more complicated here, as
we keep parsing past the prefix. We can solve it by keeping
a running pointer as we parse; its final value is the
location we want.
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Fast-import does a lot of parsing of commands and
dispatching to sub-functions. For example, given "option
foo", we might recognize "option " using starts_with, and
then hand it off to parse_option() to do the rest.

However, we do not let parse_option know that we have parsed
the first part already. It gets the full buffer, and has to
skip past the uninteresting bits. Some functions simply add
a magic constant:

  char *option = command_buf.buf + 7;

Others use strlen:

  char *option = command_buf.buf + strlen("option ");

And others use strchr:

  char *option = strchr(command_buf.buf, ' ') + 1;

All of these are brittle and easy to get wrong (especially
given that the starts_with call and the code that assumes
the presence of the prefix are far apart). Instead, we can
use skip_prefix, and just pass each handler a pointer to its
arguments.
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

It's a common idiom to match a prefix and then skip past it
with strlen, like:

  if (starts_with(foo, "bar"))
	  foo += strlen("bar");

This avoids magic numbers, but means we have to repeat the
string (and there is no compiler check that we didn't make a
typo in one of the strings).

We can use skip_prefix to handle this case without repeating
ourselves.
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

It's a common idiom to match a prefix and then skip past it
with a magic number, like:

  if (starts_with(foo, "bar"))
	  foo += 3;

This is easy to get wrong, since you have to count the
prefix string yourself, and there's no compiler check if the
string changes.  We can use skip_prefix to avoid the magic
numbers here.

Note that some of these conversions could be much shorter.
For example:

  if (starts_with(arg, "--foo=")) {
	  bar = arg + 6;
	  continue;
  }

could become:

  if (skip_prefix(arg, "--foo=", &bar))
	  continue;

However, I have left it as:

  if (skip_prefix(arg, "--foo=", &v)) {
	  bar = v;
	  continue;
  }

to visually match nearby cases which need to actually
process the string. Like:

  if (skip_prefix(arg, "--foo=", &v)) {
	  bar = atoi(v);
	  continue;
  }
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

We detect the "import-marks" capability by looking for that
string, but _without_ a trailing space. Then we skip past it
using strlen("import-marks "), with a space. So if a remote
helper gives us exactly "import-marks", we will read past
the end-of-string by one character.

This is unlikely to be a problem in practice, because such
input is malformed in the first place, and because there is
a good chance that the string has an extra NUL terminator
one character after the original (because it formerly had a
newline in it that we parsed off).

We can fix it by using skip_prefix with "import-marks ",
with the space. The other form appears to be a typo from
a515ebe9 (transport-helper: implement marks location as
capability, 2011-07-16); "import-marks" has never existed
without an argument, and it should match the "export-marks"
definition above.

Speaking of which, we can also use skip_prefix in a few
other places while we are in the function.
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Fast-import shares code between its command-line parser and
the "option" command. To do so, it strips the "--" from any
command-line options and passes them to the option parser.
However, it does not confirm that the option even begins
with "--" before blindly passing "arg + 2".

It does confirm that the option starts with "-", so the only
affected case was:

  git fast-import -

which would read uninitialized memory after the argument. We
can fix it by using skip_prefix and checking the result. As
a bonus, this gets rid of some magic numbers.
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

A submodule diff generally has content like:

  -Subproject commit [0-9a-f]{40}
  +Subproject commit [0-9a-f]{40}

When we are using "git apply --index" with a submodule, we
first apply the textual diff, and then parse that result to
figure out the new sha1.

If the diff has bogus input like:

  -Subproject commit 1234567890123456789012345678901234567890
  +bogus

we will parse the "bogus" portion. Our parser assumes that
the buffer starts with "Subproject commit", and blindly
skips past it using strlen(). This can cause us to read
random memory after the buffer.

This problem was unlikely to have come up in practice (since
it requires a malformed diff), and even when it did, we
likely noticed the problem anyway as the next operation was
to call get_sha1_hex on the random memory.

However, we can easily fix it by using skip_prefix to notice
the parsing error.
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

The skip_prefix() function returns a pointer to the content
past the prefix, or NULL if the prefix was not found. While
this is nice and simple, in practice it makes it hard to use
for two reasons:

  1. When you want to conditionally skip or keep the string
     as-is, you have to introduce a temporary variable.
     For example:

       tmp = skip_prefix(buf, "foo");
       if (tmp)
	       buf = tmp;

  2. It is verbose to check the outcome in a conditional, as
     you need extra parentheses to silence compiler
     warnings. For example:

       if ((cp = skip_prefix(buf, "foo"))
	       /* do something with cp */

Both of these make it harder to use for long if-chains, and
we tend to use starts_with() instead. However, the first line
of "do something" is often to then skip forward in buf past
the prefix, either using a magic constant or with an extra
strlen(3) (which is generally computed at compile time, but
means we are repeating ourselves).

This patch refactors skip_prefix() to return a simple boolean,
and to provide the pointer value as an out-parameter. If the
prefix is not found, the out-parameter is untouched. This
lets you write:

  if (skip_prefix(arg, "foo ", &arg))
	  do_foo(arg);
  else if (skip_prefix(arg, "bar ", &arg))
	  do_bar(arg);
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

There's no point in using:

  if (skip_prefix(buf, "foo"))

over

  if (starts_with(buf, "foo"))

as the point of skip_prefix is to return a pointer to the
data after the prefix. Using starts_with is more readable,
and will make refactoring skip_prefix easier.
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

None of these strings is modified; marking them as const
will help later refactoring.
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

This function originally took a whole config variable name
("var") and an offset ("ofs"). It checked "var+ofs" against
each color slot, but reported errors using the whole "var".

However, since 8b8e8624 (ignore unknown color configuration,
2009-12-12), it returns -1 rather than printing its own
error, and therefore only cares about var+ofs. We can drop
the ofs parameter and teach its sole caller to derive the
pointer itself.
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

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

Allow specifying only certain individual test pieces to be run
using a range notation (e.g. "t1234-test.sh --run='1-4 6 8 9-'").

* ib/test-selectively-run:
  t0000-*.sh: fix the GIT_SKIP_TESTS sub-tests
  test-lib: '--run' to run only specific tests
  test-lib: tests skipped by GIT_SKIP_TESTS say so
  test-lib: document short options in t/README

* ta/string-list-init:
  string-list: spell all values out that are given to a string_list initializer

* jm/dedup-test-config:
  t/t7810-grep.sh: remove duplicate test_config()

* dt/refs-check-refname-component-optim:
  refs.c: optimize check_refname_component()

* sk/test-cmp-bin:
  t5000, t5003: do not use test_cmp to compare binary files

* sh/enable-preloadindex:
  environment.c: enable core.preloadindex by default

* rs/read-ref-at:
  refs.c: change read_ref_at to use the reflog iterators

* jk/error-resolve-conflict-advice:
  error_resolve_conflict: drop quotations around operation
  error_resolve_conflict: rewrap advice message

Avoid unnecessary copy of previous contents when extending the
hashtable used in pack-objects.

* rs/pack-objects-no-unnecessary-realloc:
  pack-objects: use free()+xcalloc() instead of xrealloc()+memset()

* lt/log-auto-decorate:
  git log: support "auto" decorations

* jm/doc-wording-tweaks:
  Documentation: wording fixes in the user manual and glossary

* jm/format-patch-mail-sig:
  format-patch: add "--signature-file=<file>" option
  format-patch: make newline after signature conditional

Propagate the error messages from the webserver better to the
client coming over the HTTP transport.

* jk/http-errors:
  http: default text charset to iso-8859-1
  remote-curl: reencode http error messages
  strbuf: add strbuf_reencode helper
  http: optionally extract charset parameter from content-type
  http: extract type/subtype portion of content-type
  t5550: test display of remote http error messages
  t/lib-httpd: use write_script to copy CGI scripts
  test-lib: preserve GIT_CURL_VERBOSE from the environment

mailmap.file configuration names a pathname, hence should honor
~/path and ~user/path as its value.

* ow/config-mailmap-pathname:
  config: respect '~' and '~user' in mailmap.file

Allow remote-helper/fast-import based transport to rename the refs
while transferring the history.

* fc/remote-helper-refmap:
  transport-helper: remove unnecessary strbuf resets
  transport-helper: add support to delete branches
  fast-export: add support to delete refs
  fast-import: add support to delete refs
  transport-helper: add support to push symbolic refs
  transport-helper: add support for old:new refspec
  fast-export: add new --refspec option
  fast-export: improve argument parsing

"git gc --auto" was recently changed to run in the background to
give control back early to the end-user sitting in front of the
terminal, but it forgot that housekeeping involving reflogs should
be done without other processes competing for accesses to the refs.

* nd/daemonize-gc:
  gc --auto: do not lock refs in the background

* jm/t9138-style-fix:
  t9138-git-svn-authors-prog.sh fixups

* jm/instaweb-apache-24:
  git-instaweb: add support for Apache 2.4

"git remote rm" and "git remote prune" can involve removing many
refs at once, which is not a very efficient thing to do when very
many refs exist in the packed-refs file.

* jl/remote-rm-prune:
  remote prune: optimize "dangling symref" check/warning
  remote: repack packed-refs once when deleting multiple refs
  remote rm: delete remote configuration as the last

The completion code did not know about quite a few options that are
common between "git merge" and "git pull", and a couple of options
unique to "git merge".

* jk/complete-merge-pull:
  completion: add missing options for git-merge
  completion: add a note that merge options are shared

Like calloc(3), xcalloc() takes nmemb and then size.

* bg/xcalloc-nmemb-then-size:
  transport-helper.c: rearrange xcalloc arguments
  remote.c: rearrange xcalloc arguments
  reflog-walk.c: rearrange xcalloc arguments
  pack-revindex.c: rearrange xcalloc arguments
  notes.c: rearrange xcalloc arguments
  imap-send.c: rearrange xcalloc arguments
  http-push.c: rearrange xcalloc arguments
  diff.c: rearrange xcalloc arguments
  config.c: rearrange xcalloc arguments
  commit.c: rearrange xcalloc arguments
  builtin/remote.c: rearrange xcalloc arguments
  builtin/ls-remote.c: rearrange xcalloc arguments

submodule.*.ignore and diff.ignoresubmodules are used to ignore all
submodule changes in "diff" output, but it can be confusing to
apply these configuration values to status and commit.

This is a backward-incompatible change, but should be so in a good
way (aka bugfix).

* jl/status-added-submodule-is-never-ignored:
  commit -m: commit staged submodules regardless of ignore config
  status/commit: show staged submodules regardless of ignore config

Compatibility enhancement for Solaris.

* cb/byte-order:
  compat/bswap.h: fix endianness detection
  compat/bswap.h: restore preference __BIG_ENDIAN over BIG_ENDIAN
  compat/bswap.h: detect endianness on more platforms that don't use BYTE_ORDER

* jk/strbuf-tolower:
  strbuf: add strbuf_tolower function