RESULT success exit=0
PROCESS CALLS
-c core.fsync=objects,reference -c core.fsyncMethod=fsync add fixture.txt
-c core.fsync=objects,reference -c core.fsyncMethod=writeout-only add fixture.txt

ACTUAL GIT INDEX
100644 494cccbbb9c9e7872cf518c9a993420b363ea254 0	fixture.txt

Platform injected as darwin; first git failure injected by wrapper. Linux process plumbing verified; no claim of native F_FULLFSYNC or SMB verification.