Bug with git v1.8

gistfile1.txt

v@l:20:30:10:/tmp/gittest$ git init
Initialized empty Git repository in /tmp/gittest/.git/
v@l:20:30:12:/tmp/gittest$ echo q > q && git add q && git commit -m q
[master (root-commit) 9d49ad5] q
 1 files changed, 1 insertions(+), 0 deletions(-)
 create mode 100644 q
v@l:20:30:16:/tmp/gittest$ echo q2 > q && git add q && git commit -m q2
[master 27cc7c1] q2
 1 files changed, 1 insertions(+), 1 deletions(-)
v@l:20:30:23:/tmp/gittest$ git rebase -i HEAD^
usage: git diff-index [-m] [--cached] [<common diff options>] <tree-ish> [<path>...]
common diff options:
  -z            output diff-raw with lines terminated with NUL.
  -p            output patch format.
  -u            synonym for -p.
  --patch-with-raw
                output both a patch and the diff-raw format.
  --stat        show diffstat instead of patch.
  --numstat     show numeric diffstat instead of patch.
  --patch-with-stat
                output a patch and prepend its diffstat.
  --name-only   show only names of changed files.
  --name-status show names and status of changed files.
  --full-index  show full object name on index lines.
  --abbrev=<n>  abbreviate object names in diff-tree header and diff-raw.
  -R            swap input file pairs.
  -B            detect complete rewrites.
  -M            detect renames.
  -C            detect copies.
  --find-copies-harder
                try unchanged files as candidate for copy detection.
  -l<n>         limit rename attempts up to <n> paths.
  -O<file>      reorder diffs according to the <file>.
  -S<string>    find filepair whose only one side contains the string.
  --pickaxe-all
                show all files diff when -S is used and hit is found.
  -a  --text    treat all files as text.

Cannot rebase: Your index contains uncommitted changes.
Please commit or stash them.

v@l:20:33:01:/tmp/gittest$ strace -o qqq -fe execve git rebase -i HEAD^ > /dev/null 2> /dev/null 
v@l:20:33:09:/tmp/gittest$ tail qqq
9610  --- SIGCHLD (Child exited) @ 0 (0) ---
9633  execve("/usr/local//libexec/git-core/git", ["git", "rev-parse", "--verify", "HEAD"], [/* 29 vars */]) = 0
9610  --- SIGCHLD (Child exited) @ 0 (0) ---
9634  execve("/usr/local//libexec/git-core/git", ["git", "update-index", "-q", "--ignore-submodules", "--refresh"], [/* 29 vars */]) = 0
9610  --- SIGCHLD (Child exited) @ 0 (0) ---
9635  execve("/usr/local//libexec/git-core/git", ["git", "diff-files", "--quiet", "--ignore-submodules"], [/* 29 vars */]) = 0
9610  --- SIGCHLD (Child exited) @ 0 (0) ---
9636  execve("/usr/local//libexec/git-core/git", ["git", "diff-index", "--cached", "--quiet", "--ignore-submodules", "HEAD", "--"], [/* 29 vars */]) = 0
9610  --- SIGCHLD (Child exited) @ 0 (0) ---
9609  --- SIGCHLD (Child exited) @ 0 (0) ---


v@l:20:33:14:/tmp/gittest$ "git" "diff-index" "--cached" "--quiet" "--ignore-submodules" "HEAD" "--"
usage: git diff-index [-m] [--cached] [<common diff options>] <tree-ish> [<path>...]
common diff options:
.........

v@l:20:34:00:/tmp/gittest$ "git" --version
git version 1.7.8.5
v@l:20:34:08:/tmp/gittest$ "/usr/bin/git" "diff-index" "--cached" "--quiet" "--ignore-submodules" "HEAD" "--"
v@l:20:34:30:/tmp/gittest$ "/usr/bin/git" --version
git version 1.7.2.5

Note: the problem resolved by full rebuild ("make clean; make" of Git source)