[BUG] merge-recursive triggered "BUG"

As a part of my today's merge, I used 'next' that contains b2c8c0a (merge-recursive: When we detect we can skip an update, actually skip it, 2011-02-28) to merge 'maint' into 'master' to propagate older releases up.

It triggered a "BUG" per merged path, and I bisected this breakage down to the said commit. Luckily 'master' is not contaminated with the breakage, so I used it to finish today's work.

When I push out the result from today, you can reproduce it with

    git checkout 0631623 ;# master to acquire changes from maint
    git merge [-s recursive] fbcda3c

I suspect that the new codepath introduced by b2c8c0a needs to pay attention to the merge depth (for example, does it make any sense at all to run lstat() when you are doing recursive common parent synthesis?), but I didn't dig into it.

The command fails with this output:

error: addinfo_cache failed for path 'builtin/add.c'
error: addinfo_cache failed for path 'builtin/apply.c'
error: addinfo_cache failed for path 'builtin/branch.c'
error: addinfo_cache failed for path 'builtin/checkout.c'
error: addinfo_cache failed for path 'builtin/commit.c'
error: addinfo_cache failed for path 'builtin/config.c'
error: addinfo_cache failed for path 'builtin/diff-files.c'
error: addinfo_cache failed for path 'builtin/diff.c'
error: addinfo_cache failed for path 'builtin/fast-export.c'
error: addinfo_cache failed for path 'builtin/grep.c'
error: addinfo_cache failed for path 'builtin/hash-object.c'
error: addinfo_cache failed for path 'builtin/init-db.c'
error: addinfo_cache failed for path 'builtin/log.c'
error: addinfo_cache failed for path 'builtin/merge.c'
error: addinfo_cache failed for path 'builtin/push.c'
error: addinfo_cache failed for path 'builtin/rerere.c'
error: addinfo_cache failed for path 'builtin/update-index.c'
error: addinfo_cache failed for path 't/t7810-grep.sh'
BUG: There are unmerged index entries:
BUG: 1 builtin/add.cBUG: 2 builtin/add.cBUG: 3 builtin/add.cBUG: 1 builtin/apply.cBUG: 2 builtin/apply.cBUG: 3 builtin/apply.cBUG: 1 builtin/branch.cBUG: 2 builtin/branch.cBUG: 3 builtin/branch.cBUG: 1 builtin/checkout.cBUG: 2 builtin/checkout.cBUG: 3 builtin/checkout.cBUG: 1 builtin/commit.cBUG: 2 builtin/commit.cBUG: 3 builtin/commit.cBUG: 1 builtin/config.cBUG: 2 builtin/config.cBUG: 3 builtin/config.cBUG: 1 builtin/diff-files.cBUG: 2 builtin/diff-files.cBUG: 3 builtin/diff-files.cBUG: 1 builtin/diff.cBUG: 2 builtin/diff.cBUG: 3 builtin/diff.cBUG: 1 builtin/fast-export.cBUG: 2 builtin/fast-export.cBUG: 3 builtin/fast-export.cBUG: 1 builtin/grep.cBUG: 2 builtin/grep.cBUG: 3 builtin/grep.cBUG: 1 builtin/hash-object.cBUG: 2 builtin/hash-object.cBUG: 3 builtin/hash-object.cBUG: 1 builtin/in
 it-db.cBUG: 2 builtin/init-db.cBUG: 3 builtin/init-db.cBUG: 1 builtin/log.cBUG: 2 builtin/log.cBUG: 3 builtin/log.cBUG: 1 builtin/merge.cBUG: 2 builtin/merge.cBUG: 3 builtin/merge.cBUG: 1 builtin/push.cBUG: 2 builtin/push.cBUG: 3 builtin/push.cBUG: 1 builtin/rerere.cBUG: 2 builtin/rerere.cBUG: 3 builtin/rerere.cBUG: 1 builtin/update-index.cBUG: 2 builtin/update-index.cBUG: 3 builtin/update-index.cBUG: 1 t/t7810-grep.shBUG: 2 t/t7810-grep.shBUG: 3 t/t7810-grep.shfatal: Bug in merge-recursive.c

Thanks.