I've been toying with a git-remote-svn which uses fast-import (by advertising the 'import' capability) to get data into Git. Unfortunately, I can't get the result of any commands issued to fast-import, as its stdout is not redirected, and the remote helper API offers no alternative.
I tried modifiying transport-helper.c to force redirection (fast-import's stdout -> remote helper's stdin), but that breaks test t5800 (and possibly others). Is this a bug, or intended behaviour? Am I missing something?