Please describe the problem.
When exporting a treeish with a subdir to a dir special remote, it fails with the error:
git annex export master:subdir --to exportdir
fatal: Path 'subdir:' does not exist (neither on disk nor in the index).
git-annex: unknown tree
I tried other treeish variations such as :./subdir, master:subdir but it didn't work either. What is very strange to me is the ':' appended at the end of the path in the error. Any idea what is going on here ?
What steps will reproduce the problem?
mkdir annex
mv annex
git init annex
git annex init --version=6
touch a.txt
mkdir subdir
touch subdir/b.txt
git commit -m "initial commit"
mkdir ../exportdir
git annex initremote exportdir type=directory directory=../exportdir/ encryption=none exporttree=yes
git annex export master:subdir --to exportdir
fatal: Path 'subdir:' does not exist (neither on disk nor in the index).
git-annex: unknown tree
What version of git-annex are you using? On what operating system?
git annex version
git-annex version: 6.20171003
build flags: Assistant Webapp Pairing Testsuite S3(multipartupload)(storageclasses) WebDAV Inotify DBus DesktopNotify ConcurrentOutput TorrentParser MagicMime Feeds Quvi
dependency versions: aws-0.13.0 bloomfilter-2.0.1.0 cryptonite-0.10 DAV-1.2 feed-0.3.10.4 ghc-7.10.3 http-client-0.4.26.2 persistent-sqlite-2.2 torrent-10000.0.0 uuid-1.3.11 yesod-1.4.2
key/value backends: SHA256E SHA256 SHA512E SHA512 SHA224E SHA224 SHA384E SHA384 SHA3_256E SHA3_256 SHA3_512E SHA3_512 SHA3_224E SHA3_224 SHA3_384E SHA3_384 SKEIN256E SKEIN256 SKEIN512E SKEIN512 SHA1E SHA1 MD5E MD5 WORM URL
remote types: git gcrypt p2p S3 bup directory rsync web bittorrent webdav tahoe glacier ddar hook external
local repository version: 6
supported repository versions: 3 5 6
upgrade supported from repository versions: 0 1 2 3 4 5
operating system: linux x86_64
Have you had any luck using git-annex before? (Sometimes we get tired of reading bug reports all day and a lil' positive end note does wonders)
Yep, it has been a long time since I used it but I am back to see what I can do to manage my files properly 
Well, I can answer myself now. It wasn't working because my version of git was too old. I updated to version 2.18.0 and it works very well now ! It might be a good idea to find and specify the minimal git version needed to make this work next in the man page of git annex export for instance
It wasn't upgrading git that fixed it. The bug you reported was present in git-annex versions before 6.20171109. You had an older version listed in the bug report, so I assume you also upgraded git-annex to the fixed version.