http: add option to enable 100 Continue responses

When using GSS-Negotiate authentication with libcurl, the
authentication provided will change every time, and so the probe
that git uses to determine if authentication is needed is not
sufficient to guarantee that data can be sent.  If the data fits
entirely in http.postBuffer bytes, the data can be rewound and
resent if authentication fails; otherwise, a 100 Continue must be
requested in this case.

The cURL library can send an "Expect: 100 continue" if a certain
amount of data is to be uploaded, but when using chunked data, we
deliberately and unconditionally disable this behaviour, because
there are many proxy servers in the wild that do not handle
"100 continue" correctly.

Add an option http.continue, which defaults to disabled, to control
whether this header is sent; this can be used when the user knows
the destination server and all the proxies between the server and
the client handle "100 continue" correctly.

Signed-off-by: Brian M. Carlson <sandals@crustytoothpaste.net>
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>
http.c: Spell the null pointer as NULL

Commit 1bbcc224 ("http: refactor options to http_get_*", 28-09-2013)
changed the type of final 'options' argument of the http_get_file()
function from an int to an 'struct http_get_options' pointer.
However, it neglected to update the (single) call site. Since this
call was passing '0' to that argument, it was (correctly) being
interpreted as a null pointer. Change to argument to NULL.

Noticed by sparse. ("Using plain integer as NULL pointer")

Signed-off-by: Ramsay Jones <ramsay@ramsay1.demon.co.uk>
Acked-by: Jeff King <peff@peff.net>
Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
entry.c: convert checkout_entry to use strbuf

The old code does not do boundary check so any paths longer than
PATH_MAX can cause buffer overflow. Replace it with strbuf to handle
paths of arbitrary length.

The OS may reject if the path is too long though. But in that case we
report the cause (e.g. name too long) and usually move on to checking
out the next entry.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
checkout_entry(): clarify the use of topath[] parameter

The said function has this signature:

	extern int checkout_entry(struct cache_entry *ce,
				  const struct checkout *state,
				  char *topath);

At first glance, it might appear that the caller of checkout_entry()
can specify to which path the contents are written out by the last
parameter, and it is tempting to add "const" in front of its type.

In reality, however, topath[] is to point at a buffer to store the
temporary path generated by the callchain originating from this
function, and the temporary path is always short, much shorter than
the buffer prepared by its only caller in builtin/checkout-index.c.

Document the code a bit to clarify so that future callers know how
to use the function better.

Noticed-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
drop redundant semicolon in empty while

The extra semi-colon is harmless, since we really do want
the while loop to do nothing. But it does trigger a warning
from clang.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
silence gcc array-bounds warning

In shorten_unambiguous_ref, we build and cache a reverse-map of the
rev-parse rules like this:

  static char **scanf_fmts;
  static int nr_rules;
  if (!nr_rules) {
	  for (; ref_rev_parse_rules[nr_rules]; nr_rules++)
		  ... generate scanf_fmts ...
  }

where ref_rev_parse_rules is terminated with a NULL pointer.
Compiling with "gcc -O2 -Wall" does not cause any problems, but
compiling with "-O3 -Wall" generates:

  $ make CFLAGS='-O3 -Wall' refs.o
  refs.c: In function ‘shorten_unambiguous_ref’:
  refs.c:3379:29: warning: array subscript is above array bounds [-Warray-bounds]
     for (; ref_rev_parse_rules[nr_rules]; nr_rules++)

Curiously, we can silence this by explicitly nr_rules to 0
in the beginning of the loop, even though the compiler
should be able to tell that we follow this code path only
when nr_rules is already 0.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
for-each-ref: avoid loading objects to print %(objectname)

If you ask for-each-ref to print each ref and its object,
like:

  git for-each-ref --format='%(objectname) %(refname)'

this should involve little more work than looking at the ref
files (and packed-refs) themselves. However, for-each-ref
will actually load each object from disk just to print its
sha1. For most repositories, this isn't a big deal, but it
can be noticeable if you have a large number of refs to
print. Here are best-of-five timings for the command above
on a repo with ~10K refs:

  [before]
  real    0m0.112s
  user    0m0.092s
  sys     0m0.016s

  [after]
  real    0m0.014s
  user    0m0.012s
  sys     0m0.000s

This patch checks for %(objectname) and %(objectname:short)
before we actually parse the object (and the rest of the
code is smart enough to avoid parsing if we have filled all
of our placeholders).

Note that we can't simply move the objectname parsing code
into the early loop. If the "deref" form %(*objectname) is
used, then we do need to parse the object in order to peel
the tag. So instead of moving the code, we factor it out
into a separate function that can be called for both cases.

While we're at it, we add some basic tests for the
dereferenced placeholders, which were not tested at all
before. This helps ensure we didn't regress that case.

Signed-off-by: Jeff King <peff@peff.net>
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>
Merge branch 'jk/http-auth-redirects' into jch

Handle the case where http transport gets redirected during the
authorization request better.

* jk/http-auth-redirects:
  http.c: Spell the null pointer as NULL
  remote-curl: rewrite base url from info/refs redirects
  remote-curl: store url as a strbuf
  remote-curl: make refs_url a strbuf
  http: update base URLs when we see redirects
  http: provide effective url to callers
  http: hoist credential request out of handle_curl_result
  http: refactor options to http_get_*
  http_request: factor out curlinfo_strbuf
  http_get_file: style fixes

# Conflicts:
# 	http.c
# 	remote-curl.c
Merge branch 'jc/upload-pack-send-symref' into jch

One long-standing flaw in the pack transfer protocol used by "git
clone" was that there was no way to tell the other end which branch
"HEAD" points at, and the receiving end needed to guess.  A new
capability has been defined in the pack protocol to convey this
information so that cloning from a repository with more than one
branches pointing at the same commit where the HEAD is at now
reliably sets the initial branch in the resulting repository.

* jc/upload-pack-send-symref:
  t5570: Update for clone-progress-to-stderr branch
  t5570: Update for symref capability
  clone: test the new HEAD detection logic
  connect: annotate refs with their symref information in get_remote_head()
  connect.c: make parse_feature_value() static
  upload-pack: send non-HEAD symbolic refs
  upload-pack: send symbolic ref information as capability
  upload-pack.c: do not pass confusing cb_data to mark_our_ref()
  t5505: fix "set-head --auto with ambiguous HEAD" test
Merge branch 'sb/repack-in-c' into jch

Finishing touches to update documentation.

* sb/repack-in-c:
  Reword repack documentation to no longer state it's a script
### match next
Merge branch 'jl/submodule-mv' into jch

Moving a regular file in a repository with a .gitmodules file was
producing a warning 'Could not find section in .gitmodules where
path=<filename>'.

* jl/submodule-mv:
  mv: Fix spurious warning when moving a file in presence of submodules
Merge branch 'sg/t3600-nul-sha1-fix' into jch

* sg/t3600-nul-sha1-fix:
  t3600: fix broken "choking git rm" test