drop, move, mirror: when two files have the same content, honor the max numcopies and requiredcopies

Eg, before with a .gitattributes like:

*.2 annex.numcopies=2
*.1 annex.numcopies=1

And foo.1 and foo.2 having the same content and key, git-annex drop foo.1 foo.2
would succeed, leaving just 1 copy, despite foo.2 needing 2 copies.
It dropped foo.1 first and then skipped foo.2 since its content was gone.

Now that the keys database includes locked files, this longstanding wart
can be fixed.

Sponsored-by: Noam Kremen on Patreon

Command/Drop.hs

@@ -227,7 +227,7 @@ checkRequiredContent (PreferredContentChecked False) u k afile =
  - copies on other semitrusted repositories. -}
 checkDropAuto :: Bool -> Maybe Remote -> AssociatedFile -> Key -> (NumCopies -> MinCopies -> CommandStart) -> CommandStart
 checkDropAuto automode mremote afile key a =
-	go =<< getAssociatedFileNumMinCopies afile
+	go =<< getSafestNumMinCopies afile key
   where
 	go (numcopies, mincopies)
 		| automode = do

Command/Mirror.hs

@@ -68,7 +68,7 @@ startKey o afile (si, key, ai) = case fromToOptions o of
 	ToRemote r -> checkFailedTransferDirection ai Upload $ ifM (inAnnex key)
 		( Command.Move.toStart Command.Move.RemoveNever afile key ai si =<< getParsed r
 		, do
-			(numcopies, mincopies) <- getAssociatedFileNumMinCopies afile
+			(numcopies, mincopies) <- getSafestNumMinCopies afile key
 			Command.Drop.startRemote pcc afile ai si numcopies mincopies key =<< getParsed r
 		)
 	FromRemote r -> checkFailedTransferDirection ai Download $ do
@@ -81,7 +81,7 @@ startKey o afile (si, key, ai) = case fromToOptions o of
 				)
 			Right False -> ifM (inAnnex key)
 				( do
-					(numcopies, mincopies) <- getAssociatedFileNumMinCopies afile
+					(numcopies, mincopies) <- getSafestNumMinCopies afile key
 					Command.Drop.startLocal pcc afile ai si numcopies mincopies key []
 				, stop
 				)

Command/Move.hs

@@ -166,7 +166,7 @@ toPerform dest removewhen key afile fastcheck isthere = do
 			willDropMakeItWorse srcuuid destuuid deststartedwithcopy key afile >>= \case
 				DropAllowed -> drophere setpresentremote contentlock "moved"
 				DropCheckNumCopies -> do
-					(numcopies, mincopies) <- getAssociatedFileNumMinCopies afile
+					(numcopies, mincopies) <- getSafestNumMinCopies afile key
 					(tocheck, verified) <- verifiableCopies key [srcuuid]
 					verifyEnoughCopiesToDrop "" key (Just contentlock)
 						 numcopies mincopies [srcuuid] verified
@@ -245,7 +245,7 @@ fromPerform src removewhen key afile = do
 		willDropMakeItWorse srcuuid destuuid deststartedwithcopy key afile >>= \case
 			DropAllowed -> dropremote "moved"
 			DropCheckNumCopies -> do
-				(numcopies, mincopies) <- getAssociatedFileNumMinCopies afile
+				(numcopies, mincopies) <- getSafestNumMinCopies afile key
 				(tocheck, verified) <- verifiableCopies key [Remote.uuid src]
 				verifyEnoughCopiesToDrop "" key Nothing numcopies mincopies [Remote.uuid src] verified
 					tocheck (dropremote . showproof) faileddropremote