Merge branch 'ex/deprecate-empty-pathspec-as-match-all'

An empty string used as a pathspec element has always meant
'everything matches', but it is too easy to write a script that
finds a path to remove in $path and run 'git rm "$paht"', which
ends up removing everything.  Start warning about this use of an
empty string used for 'everything matches' and ask users to use a
more explicit '.' for that instead.

The hope is that existing users will not mind this change, and
eventually the warning can be turned into a hard error, upgrading
the deprecation into removal of this (mis)feature.

* ex/deprecate-empty-pathspec-as-match-all:
pathspec: warn on empty strings as pathspec

diff --cc pathspec.c
Simple merge

diff --cc t/t3700-add.sh
index 53c0cb6dea686ac872c219b746a0c24b3d505416,05379d0a4a5c5312896f8cc13e286ebb37c517e7..f3a4b4a913f344ce140344ec7b70482a6d36bcbe
--- 1/t/t3700-add.sh
--- 2/t/t3700-add.sh
+++ b/t/t3700-add.sh
@@@ -331,71 -332,9 +331,76 @@@ test_expect_success 'git add --dry-run 
        test_i18ncmp expect.err actual.err
  '
  
+ test_expect_success 'git add empty string should invoke warning' '
+       git add "" 2>output &&
+       test_i18ngrep "warning: empty strings" output
+ '
+ 
 +test_expect_success 'git add --chmod=[+-]x stages correctly' '
 +      rm -f foo1 &&
 +      echo foo >foo1 &&
 +      git add --chmod=+x foo1 &&
 +      test_mode_in_index 100755 foo1 &&
 +      git add --chmod=-x foo1 &&
 +      test_mode_in_index 100644 foo1
 +'
 +
 +test_expect_success POSIXPERM,SYMLINKS 'git add --chmod=+x with symlinks' '
 +      git config core.filemode 1 &&
 +      git config core.symlinks 1 &&
 +      rm -f foo2 &&
 +      echo foo >foo2 &&
 +      git add --chmod=+x foo2 &&
 +      test_mode_in_index 100755 foo2
 +'
 +
 +test_expect_success 'git add --chmod=[+-]x changes index with already added file' '
 +      rm -f foo3 xfoo3 &&
 +      echo foo >foo3 &&
 +      git add foo3 &&
 +      git add --chmod=+x foo3 &&
 +      test_mode_in_index 100755 foo3 &&
 +      echo foo >xfoo3 &&
 +      chmod 755 xfoo3 &&
 +      git add xfoo3 &&
 +      git add --chmod=-x xfoo3 &&
 +      test_mode_in_index 100644 xfoo3
 +'
 +
 +test_expect_success POSIXPERM 'git add --chmod=[+-]x does not change the working tree' '
 +      echo foo >foo4 &&
 +      git add foo4 &&
 +      git add --chmod=+x foo4 &&
 +      ! test -x foo4
 +'
 +
 +test_expect_success 'no file status change if no pathspec is given' '
 +      >foo5 &&
 +      >foo6 &&
 +      git add foo5 foo6 &&
 +      git add --chmod=+x &&
 +      test_mode_in_index 100644 foo5 &&
 +      test_mode_in_index 100644 foo6
 +'
 +
 +test_expect_success 'no file status change if no pathspec is given in subdir' '
 +      mkdir -p sub &&
 +      (
 +              cd sub &&
 +              >sub-foo1 &&
 +              >sub-foo2 &&
 +              git add . &&
 +              git add --chmod=+x &&
 +              test_mode_in_index 100644 sub-foo1 &&
 +              test_mode_in_index 100644 sub-foo2
 +      )
 +'
 +
 +test_expect_success 'all statuses changed in folder if . is given' '
 +      git add --chmod=+x . &&
 +      test $(git ls-files --stage | grep ^100644 | wc -l) -eq 0 &&
 +      git add --chmod=-x . &&
 +      test $(git ls-files --stage | grep ^100755 | wc -l) -eq 0
 +'
 +
  test_done