difftool: Handle finding mergetools/ in a path with spaces

Use the original File::Find implementation from bf73fc2 (difftool:
print list of valid tools with '--tool-help', 2012-03-29) so that we
properly handle mergetools/ being located in a path containing
spaces.

One small difference is that we avoid using a global variable by
passing a reference to the list of tools.

Signed-off-by: David Aguilar <davvid@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
difftool: Check all return codes from compare()

Handle the case where compare() is unable to read its inputs.
Emit a warning so that the user knows that something went wrong.

We may later want to restructure the code so that we can inhibit
tempdir cleanup when this condition is reached.

Signed-off-by: David Aguilar <davvid@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Make 'git submodule update --force' always check out submodules.

Currently, it will only do a checkout if the sha1 registered in the containing
repository doesn't match the HEAD of the submodule, regardless of whether the
submodule is dirty.  As discussed on the mailing list, the '--force' flag is a
strong indicator that the state of the submodule is suspect, and should be reset
to HEAD.

Signed-off-by: Stefan Zager <szager@google.com>
Acked-by: Jens Lehmann <Jens.Lehmann@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
difftool: Wrap long lines for readability

Keep everything within 80 columns.  Wrap the user-facing messages too.

Signed-off-by: David Aguilar <davvid@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
difftool: Handle compare() returning -1

Keep the temporary directory around when compare()
cannot read its input files, which is indicated by -1.

Defer tempdir creation to allow an early exit in setup_dir_diff().
Wrap the rest of the entry points in an exit_cleanup() function
to handle removing temporary files and error reporting.

Print the temporary files' location so that the user can
recover them.

Signed-off-by: David Aguilar <davvid@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
difftool: Disable --symlinks on cygwin

Symlinks are not ubiquitous on Windows so make --no-symlinks the default.

Signed-off-by: David Aguilar <davvid@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Merge branch 'jk/maint-checkout-orphan-check-fix' into next

Will merge to 'next', later down to older maintenance releases.

* jk/maint-checkout-orphan-check-fix:
  checkout: don't confuse ref and object flags
Merge branch 'dg/submodule-in-dismembered-working-tree' into next

Will merge to 'next'.

* dg/submodule-in-dismembered-working-tree:
  git-submodule: work with GIT_DIR/GIT_WORK_TREE
Merge branch 'sz/submodule-force-update' into next

Will merge to 'next'.
We may want a documentation update and a few tests on top, though.

* sz/submodule-force-update:
  Make 'git submodule update --force' always check out submodules.
test: rename $satisfied to $satisfied_prereq

All other shell variables that globally keep track of prerequisite
related states have "prereq" somewhere in their names.  Be consistent
and avoid name crashes.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
test: allow prerequisite to be evaluated lazily

The test prerequisite mechanism is a useful way to allow some tests
in a test script to be skipped in environments that do not offer
certain features (e.g. checking how symbolic links are handled on
filesystems that do not support them).  It is OK for commonly used
prerequisites to be always tested during start-up of test script by
having a codeblock that tests a feature and calls test_set_prereq,
but for an uncommon feature, forcing 90% of scripts to pay the same
probing overhead for prerequisite they do not care about is wasteful.

Introduce a mechanism to probe the prerequiste lazily.  Changes are:

 - test_lazy_prereq () function, which takes the name of the
   prerequisite it probes and the script to probe for it, is
   added.  This only registers the name of the prerequiste that can
   be lazily probed and the script to eval (without running).

 - test_have_prereq() function (which is used by test_expect_success
   and also can be called directly by test scripts) learns to look
   at the list of prerequisites that can be lazily probed, and the
   prerequisites that have already been probed that way.

Update the codeblock to probe and set SYMLINKS prerequisite using
the new mechanism as an example.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
test-lib: provide case insensitivity as a prerequisite

Case insensitivity plays a role in several tests and is tested in several
tests. Therefore, move the test from t003 into the test lib and use the
prerequisite in t0003.

Signed-off-by: Michael J Gruber <git@drmicha.warpmail.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
t0050: use the CASE_INSENSITIVE_FS test prereq

Signed-off-by: Michael J Gruber <git@drmicha.warpmail.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
t0050: use the SYMLINKS test prereq

Signed-off-by: Michael J Gruber <git@drmicha.warpmail.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
test-lib: provide UTF8 behaviour as a prerequisite

UTF8 behaviour of the filesystem (conversion from nfd to nfc)  plays a
role in several tests and is tested in several tests. Therefore, move
the test from t0050 into the test lib and use the prerequisite in t0050.

Signed-off-by: Michael J Gruber <git@drmicha.warpmail.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Merge branch 'da/difftool-updates' into next

"git difftool --dir-diff" learned to use symbolic links to prepare
temporary copy of the working tree when available.

I think this topic can wait til the next cycle.

* da/difftool-updates:
  difftool: Disable --symlinks on cygwin
  difftool: Handle compare() returning -1
  difftool: Wrap long lines for readability
  difftool: Check all return codes from compare()
  difftool: Handle finding mergetools/ in a path with spaces
Merge branch 'jk/help-plug-memleak' into next

* jk/help-plug-memleak:
  help.c::exclude_cmds(): plug a leak
  help.c::uniq: plug a leak
Merge branch 'jc/test-prereq' into next

Teaches the test framework to probe rarely used prerequistes lazily,
and make use of it for detecting SYMLINKS, CASE_INSENSITIVE_FS and
NKD/NKC MacOS x gotcha.

* jc/test-prereq:
  test-lib: provide UTF8 behaviour as a prerequisite
  t0050: use the SYMLINKS test prereq
  t0050: use the CASE_INSENSITIVE_FS test prereq
  test-lib: provide case insensitivity as a prerequisite
  test: allow prerequisite to be evaluated lazily
  test: rename $satisfied to $satisfied_prereq
Merge branch 'jk/autoident-test' into next

Will merge to 'next'.

* jk/autoident-test:
  t7502: test early quit from commit with bad ident
  t7502: handle systems where auto-identity is broken
  t7502: drop confusing test_might_fail call
  t7502: narrow checks for author/committer name in template
  t7502: properly quote GIT_EDITOR
  t7502: clean up fake_editor tests
Revert "Merge branch 'jc/test-prereq' into next"

This reverts commit 0e21c36f8a8021296e10cc411e42f53e8b6900b2,
reversing changes made to bd57cb8e61b16adc3b4ab8c84074ff452c0e56c5,
to rebuild the lazy test prerequiste topic.  As it won't be too late
in the upcoming release, we can keep the script more readable from
the beginning this way.