Crash on empty pickaxe argument

[Jared Van Bortel <cebtenzzre@gmail.com>]

Hi all,

I fat-fingered my enter key today and noticed this crash:

$ git --version
git version 2.48.1
$ mkdir foo && cd foo
$ git init
<snip>
$ git commit --allow-empty -m "foo"
[master (root-commit) ed4e080] foo
$ git log -S ""
BUG: diffcore-pickaxe.c:241: should have needle under -G or -S
[1]    65421 IOT instruction (core dumped)  git log -S ""
$ git log -G ""
BUG: diffcore-pickaxe.c:241: should have needle under -G or -S
[1]    65457 IOT instruction (core dumped)  git log -G ""


Well, it says BUG right there. It probably shouldn't crash. Relevant
backtrace for -S:

#3  0x00007ffff7ce7582 in __GI_abort () at abort.c:73
#4  0x00005555558689aa in BUG_vfl (file=<optimized out>, line=<optimized out>, fmt=0x5555558ed498 "should have needle under -G or -S", params=0x7fffffffbf70)
    at /usr/src/debug/git/git-2.48.1/usage.c:318
#5  BUG_fl (file=<optimized out>, line=<optimized out>, fmt=0x5555558ed498 "should have needle under -G or -S") at /usr/src/debug/git/git-2.48.1/usage.c:335
#6  0x000055555571527f in diffcore_pickaxe (o=0x7fffffffca90) at /usr/src/debug/git/git-2.48.1/diffcore-pickaxe.c:241
#7  diffcore_std (options=0x7fffffffca90) at /usr/src/debug/git/git-2.48.1/diff.c:7079
#8  0x00005555558b2788 in log_tree_diff_flush.isra.0 (opt=0x7fffffffc4d0) at /usr/src/debug/git/git-2.48.1/log-tree.c:929
#9  0x000055555574b2e4 in log_tree_diff (opt=0x7fffffffc4d0, commit=0x5555559b7b80, log=0x7fffffffc300) at /usr/src/debug/git/git-2.48.1/log-tree.c:1120
#10 log_tree_commit (opt=0x7fffffffc4d0, commit=0x5555559b7b80) at /usr/src/debug/git/git-2.48.1/log-tree.c:1188
#11 0x00005555555e68c8 in cmd_log_walk_no_free (rev=<optimized out>) at builtin/log.c:528
#12 cmd_log_walk_no_free (rev=rev@entry=0x7fffffffc4d0) at builtin/log.c:506
#13 0x00005555555e74bf in cmd_log_walk (rev=0x7fffffffc4d0) at builtin/log.c:569
#14 cmd_log (argc=3, argv=0x5555559b0790, prefix=0x0, repo=<optimized out>) at builtin/log.c:950
#15 0x000055555555e56c in run_builtin (p=0x555555977f40 <commands.lto_priv+1440>, argc=<optimized out>, argv=<optimized out>, repo=0x555555986d40 <the_repo.lto_priv>)
    at /usr/src/debug/git/git-2.48.1/git.c:480
#16 handle_builtin (args=args@entry=0x7fffffffd4a0) at /usr/src/debug/git/git-2.48.1/git.c:740
#17 0x000055555555ec34 in run_argv (args=0x7fffffffd4a0) at /usr/src/debug/git/git-2.48.1/git.c:807
#18 0x00005555555598a1 in cmd_main (argc=<optimized out>, argv=<optimized out>) at /usr/src/debug/git/git-2.48.1/git.c:947
#19 main (argc=<optimized out>, argv=<optimized out>) at /usr/src/debug/git/git-2.48.1/common-main.c:64


Thanks,
Jared