submodule: clarify logic in show_submodule_summary

There are two uses of the "left" and "right" commit variables that
make it hard to be sure what values they have (both for the reader,
and for gcc, which wrongly complains that they might be used
uninitialized).

The function starts with a cascading if statement, checking that the
input sha1s exist, and finally working up to preparing a revision
walk. We only prepare the walk if the cascading conditional did not
find any problems, which we check by seeing whether it set the
"message" variable or not. It's simpler and more obvious to just add
a condition to the end of the cascade.

Later, we check the same "message" variable when deciding whether to
clear commit marks on the left/right commits; if it is set, we
presumably never started the walk. This is wrong, though; we might
have started the walk and munged commit flags, only to encounter an
error afterwards. We should always clear the flags on left/right if
they exist, whether the walk was successful or not.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
match-trees: simplify score_trees() using tree_entry()

Convert the loop in score_trees() to tree_entry().  The code becomes
shorter and simpler because the calls to update_tree_entry() are not
needed any more.

Another benefit is that we need less variables to track the current
tree entries; as a side-effect of that the compiler has an easier
job figuring out the control flow and thus can avoid false warnings
about uninitialized variables.

Using struct name_entry also allows the use of tree_entry_len() for
finding the path length instead of strlen(), which may be slightly
more efficient.

Also unify the handling of missing entries in one of the two trees
(i.e. added or removed files): Just set cmp appropriately first, no
matter if we ran off the end of a tree or if we actually have two
entries to compare, and check its value a bit later without
duplicating the handler code.

Signed-off-by: Rene Scharfe <rene.scharfe@lsrfire.ath.cx>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Make core.sharedRepository work under cygwin 1.7

When core.sharedRepository is used, set_shared_perm() in path.c
needs lstat() to return the correct POSIX permissions.

The default for cygwin is core.ignoreCygwinFSTricks = false, which
means that the fast implementation in do_stat() is used instead of
lstat().

lstat() under cygwin uses the Windows security model to implement
POSIX-like permissions.  The user, group or everyone bits can be set
individually.

do_stat() simplifes the file permission bits, and may return a wrong
value.  The read-only attribute of a file is used to calculate the
permissions, resulting in either rw-r--r-- or r--r--r--

One effect of the simplified do_stat() is that t1301 fails.

Add a function cygwin_get_st_mode_bits() which returns the POSIX
permissions.  When not compiling for cygwin, true_mode_bits() in
path.c is used.

Side note:

t1301 passes under cygwin 1.5.

The "user write" bit is synchronized with the "read only" attribute
of a file:

    $ chmod 444 x
    $ attrib x
    A    R     C:\temp\pt\x

    cygwin 1.7 would show
    A          C:\temp\pt\x

Signed-off-by: Torsten Bögershausen <tboegi@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
commit-tree: document -S option consistently

Commit ba3c69a9 (commit: teach --gpg-sign option, 2011-10-05) added the
-S option but documented it in the command usage without indicating that
the value is optional and forgot to mention it in the manpage.  Later
commit 098bbdc3 (Add -S, --gpg-sign option to manpage of "git commit",
2012-10-21) documented the option in the porcelain manpage.

Use wording from the porcelain manpage to document the option in the
plumbing manpage.  Also update the commit-tree usage summary to indicate
that the -S value is optional to be consistent with the manpage and with
the implementation.

Signed-off-by: Brad King <brad.king@kitware.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
safe_create_leading_directories: fix race that could give a false negative

If two processes are racing to create the same directory tree, they
will both see that the directory doesn't exist, both try to mkdir(),
and one of them will fail.  This is okay, as we only care that the
directory gets created.  So, we add a check for EEXIST from mkdir,
and continue when the directory exists, taking the same codepath as
the case where the earlier stat() succeeds and finds a directory.

Signed-off-by: Steven Walter <stevenrwalter@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
log: read gpg settings for signed commit verification

"show --show-signature" and "log --show-signature" do not read the
gpg.program setting from git config, even though, commit signing,
tag signing, and tag verification honor it.

Signed-off-by: Jacob Sarvis <jsarvis@openspan.com>
Signed-off-by: Hans Brigman <hbrigman@openspan.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Avoid loading commits twice in log with diffs

If you run a log with diffs (such as -p, --raw, --stat etc.) the
current code ends up loading many objects twice.  For example, for
'log -3000 -p' my instrumentation said the objects loaded more than
once are distributed as follows:

  2008 blob
  2103 commit
  2678 tree

Fixing blobs and trees will be harder, because those are really used
within the diff engine and need some form of caching.

However, fixing the commits is easy at least at the band-aid level.
They are triggered by log_tree_diff() invoking diff_tree_sha1() on
commits, which duly loads the specified object to dereference it to a
tree.  Since log_tree_diff() knows that it works with commits and they
must have trees, we can simply pass through the trees.

We add some parse_commit() calls.  The ones for the parents are
required; we do not know at this stage if they have been looked at.
The one for the commit itself is pure paranoia, but has about the same
cost as an assertion on commit->object.parsed.

This has a quite dramatic effect on log --raw, though only a
negligible impact on log -p:

Test                      this tree         HEAD
--------------------------------------------------------------------
4000.2: log --raw -3000   0.50(0.43+0.06)   0.54(0.46+0.06) +7.0%***
4000.3: log -p -3000      2.34(2.20+0.13)   2.37(2.22+0.13) +1.2%
--------------------------------------------------------------------
Significance hints:  '.' 0.1  '*' 0.05  '**' 0.01  '***' 0.001

Signed-off-by: Thomas Rast <trast@student.ethz.ch>
Signed-off-by: Thomas Rast <trast@inf.ethz.ch>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
t1300: document some aesthetic failures of the config editor

The config-editing code used by "git config var value" is
built around the regular config callback parser, whose only
triggerable item is an actual key. As a result, it does not
know anything about section headers, which can result in
unnecessarily ugly output:

  1. When we delete the last key in a section, we should be
     able to delete the section header.

  2. When we add a key into a section, we should be able to
     reuse the same section header, even if that section did
     not have any keys in it already.

Unfortunately, fixing these is not trivial with the current
code. It would involve the config parser recording and
passing back information on each item it finds, including
headers, keys, and even comments (or even better, generating
an actual in-memory parse-tree).

Since these behaviors do not cause any functional problems
(i.e., the resulting config parses as expected, it is just
uglier than one would like), fixing them can wait until
somebody feels like substantially refactoring the parsing
code. In the meantime, let's document them as known issues
with some tests.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Merge branch 'jk/no-more-self-assignment'

This started as a topic to reduce "type var = var" self assignment
tricks that were used to squelch "variable used uninitialized perhaps?"
warning from some compilers, but resulted in rewriting logic with
a version that is simpler and easier to understand for humans.

* jk/no-more-self-assignment:
  match-trees: simplify score_trees() using tree_entry()
  submodule: clarify logic in show_submodule_summary
Merge branch 'bk/document-commit-tree-S'

* bk/document-commit-tree-S:
  commit-tree: document -S option consistently
Merge branch 'sw/safe-create-leading-dir-race'

* sw/safe-create-leading-dir-race:
  safe_create_leading_directories: fix race that could give a false negative
Merge branch 'tb/cygwin-shared-repository'

Cygwin port has a faster-but-lying lstat(2) emulation whose
incorrectness does not matter in practice except for a few
codepaths, and setting permission bits to directories is a codepath
that needs to use a more correct one.

* tb/cygwin-shared-repository:
  Make core.sharedRepository work under cygwin 1.7
Merge branch 'tr/log-tree-optim'

Optimize "log" that shows the difference between the parent and the
child.

* tr/log-tree-optim:
  Avoid loading commits twice in log with diffs
Merge branch 'js/log-gpg'

Teach "show/log" honor gpg.program configuration just like other
parts of the code that use GnuPG.

* js/log-gpg:
  log: read gpg settings for signed commit verification
Merge branch 'jk/config-with-empty-section'

Document that "git config --unset" does not remove an empty section
head after removing the last variable in a section, and adding a
new variable does not try to reuse a leftover empty section head.

* jk/config-with-empty-section:
  t1300: document some aesthetic failures of the config editor
Update draft release notes to 1.8.3

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