Two problems on alias of git

Hello.  I found 2 problems on alias of git.

The first one is that git crashes with the following situation. Without GIT_TRACE, everthing works well. But with GIT_TRACE=1, git crashes every time.

---- 8< ---- 8< ---- 8< ---- 8< ---- 8< ----
$ git remote show origin
* remote origin
  URL: git://repo.or.cz/git.git
  Remote branch merged with 'git pull' while on branch master
    master
  Tracked remote branches
    html
    maint
    man
    master
    next
    pu
    todo

$ git --version git version 1.6.2.rc0.90.g0753

$ git show HEAD | grep commit commit 3536ae331014c68a25c80b3fb530a19c8dee0f11

$ uname -a Darwin foobarbaz 9.6.1 Darwin Kernel Version 9.6.1: Sun Dec 21 19:45:33 PST 2008; root:xnu-1228.9.75~4/RELEASE_I386 i386 i386 MacBook5,2 Darwin

$ git config --get alias.l1 log --pretty=oneline

$ GIT_TRACE=1 git l1 trace: exec: 'git-l1' trace: run_command: 'git-l1' trace: exec 'git-l1' failed: No such file or directory [1] 41772 segmentation fault GIT_TRACE=1 git l1 ---- >8 ---- >8 ---- >8 ---- >8 ---- >8 ----

The second one is that git doesn't expand a kind of aliases properly, especially with double quotation marks ("). I used the following alias recently to list the last 10 commits on HEAD:

[alias]
        lr = !git l1 | head | tac

Then I want to extend this alias to list the last N commits on a branch with "git lr 20", "git lr master", "git lr master 20", etc. So that I wrote the following definition (note that the actual definition is written in a single line, though the quoted definition is folded in multiple lines for readability):

[alias]
        lr = !$SHELL -c '
                n=10;
                1="${1:-$n}";
                if ! [ "${1##[0-9]*}" = "" ]; then
                  t="$1";
                  1="${2:-$n}";
                  2="$t";
                fi;
                git --no-pager l1 --reverse -"$1" "${2:-HEAD}"
              ' __dummy__

But it doesn't work because git expands as follows:

$ git config --get alias.lr !$SHELL -c '1=${1:-10}

Double quotation marks (") are removed and the aliased string is cut at a random position. I expect that the aliased string is passed to system() as-is, but git doesn't so. Why does git behave so? Is it a bug or an intentional behavior?