fetch-pack: do not remove .git/shallow file when --depth is not specified

fetch_pack() can remove .git/shallow file when a shallow repository
becomes a full one again. This behavior is triggered incorrectly when
tags are also fetched because fetch_pack() will be called twice. At
the first fetch_pack() call:

 - shallow_lock is set up
 - alternate_shallow_file points to shallow_lock.filename, which is
   "shallow.lock"
 - commit_lock_file is called, which sets shallow_lock.filename to "".
   alternate_shallow_file also becomes "" because it points to the
   same memory.

At the second call, setup_alternate_shallow() is not called and
alternate_shallow_file remains "". It's mistaken as unshallow case and
.git/shallow is removed. The end result is a broken repository.

Fix this by always initializing alternate_shallow_file when
fetch_pack() is called. As an extra measure, check if args->depth > 0
before commit/rollback shallow file.

Reported-by: Kacper Kornet <kornet@camk.edu.pl>
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
config: do not use C function names as struct members

According to C99, section 7.1.4:

  Any function declared in a header may be additionally
  implemented as a function-like macro defined in the
  header.

Therefore calling our struct member function pointer "fgetc"
may run afoul of unwanted macro expansion when we call:

  char c = cf->fgetc(cf);

This turned out to be a problem on uclibc, which defines
fgetc as a macro and causes compilation failure.

The standard suggests fixing this in a few ways:

  1. Using extra parentheses to inhibit the function-like
     macro expansion. E.g., "(cf->fgetc)(cf)". This is
     undesirable as it's ugly, and each call site needs to
     remember to use it (and on systems without the macro,
     forgetting will compile just fine).

  2. Using #undef (because a conforming implementation must
     also be providing fgetc as a function). This is
     undesirable because presumably the implementation was
     using the macro for a performance benefit, and we are
     dropping that optimization.

Instead, we can simply use non-colliding names.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Documentation/git-merge.txt: fix formatting of example block

You need at least four dashes in a line to have it recognized as listing
block delimiter by asciidoc.

Signed-off-by: Andreas Schwab <schwab@linux-m68k.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Merge branch 'maint-1.8.2' into maint-1.8.3

* maint-1.8.2:
  Documentation/git-merge.txt: fix formatting of example block
Merge branch 'maint-1.8.3' into maint

* maint-1.8.3:
  Documentation/git-merge.txt: fix formatting of example block
Merge branch 'hv/config-from-blob' into maint

Compilation fix on platforms with fgetc() and friends defined as
macros.

* hv/config-from-blob:
  config: do not use C function names as struct members
Merge branch 'nd/fetch-pack-shallow-fix' into maint

The recent "short-cut clone connectivity check" topic broke a shallow
repository when a fetch operation tries to auto-follow tags.

* nd/fetch-pack-shallow-fix:
  fetch-pack: do not remove .git/shallow file when --depth is not specified