Add doc/bugs/Drop_--from_always_trusts_local_repository.mdwn

doc/bugs/Drop_--from_always_trusts_local_repository.mdwn

@@ -0,0 +1,44 @@
+### Please describe the problem.
+
+The command `git annex drop --from` always trusts the local repository, even if
+it is marked as untrusted.
+
+
+### What steps will reproduce the problem?
+[[!format sh """
+mkdir t u; cd t; git init; git commit --allow-empty -m "Initial commit"; git annex init "Trusted"; date > file; git annex add file; git commit -m "Add file"; cd ../u; git init; git remote add t ../t; git fetch t; git merge t/master; git annex init "Untrusted"; git annex untrust .; git annex get file; cd ../t; git remote add u ../u; git fetch u; cd ..
+"""]]
+
+Create two repositories, *t* (trusted) and *u* (untrusted). A file is in both
+repositories. When performing `git annex drop file` in repository *t*, `git
+annex` will abort because there are not enough copies. But when performing `git
+annex drop --from t file` in *u*, git annex will delete the copy.
+
+
+### What version of git-annex are you using? On what operating system?
+
+Bug was introduced with 6c31e3a8 and still exists in current master (d955cfe7).
+
+
+### Please provide any additional information below.
+
+The following change seems to solve the problem. (First time working with
+Haskell, please excuse the crude code.)
+
+[[!format diff """
+diff --git a/Command/Drop.hs b/Command/Drop.hs
+index 269c4c2..09ea99a 100644
+--- a/Command/Drop.hs
++++ b/Command/Drop.hs
+@@ -82,8 +82,9 @@ performRemote key afile numcopies remote = lockContent key $ do
+        (remotes, trusteduuids) <- Remote.keyPossibilitiesTrusted key
+        present <- inAnnex key
+        u <- getUUID
++       level <- lookupTrust u
+        let have = filter (/= uuid) $
+-               if present then u:trusteduuids else trusteduuids
++               if present && level <= SemiTrusted then u:trusteduuids else trusteduuids
+        untrusteduuids <- trustGet UnTrusted
+        let tocheck = filter (/= remote) $
+                Remote.remotesWithoutUUID remotes (have++untrusteduuids)
+"""]]