include passthrough params in --describe-other-params

Annex/SpecialRemote/Config.hs

@@ -189,7 +189,7 @@ parseRemoteConfig c rpc =
   where
 	go l c' [] =
 		let (passover, leftovers) = partition
-			(remoteConfigRestPassthrough rpc . fst)
+			(maybe (const False) fst (remoteConfigRestPassthrough rpc) . fst)
 			(M.toList c')
 		    leftovers' = filter (notaccepted . fst) leftovers
 		in if not (null leftovers')

Command/InitRemote.hs

@@ -114,22 +114,22 @@ cleanup u name c o = do
 describeOtherParamsFor :: RemoteConfig -> RemoteType -> CommandPerform
 describeOtherParamsFor c t = do
 	cp <- R.configParser t c
-	let l = mapMaybe mk $ filter notinconfig $ remoteConfigFieldParsers cp
-	liftIO $ forM_ l $ \(p, pd, vd) -> do
-		putStrLn p
-		putStrLn ("\t" ++ pd)
-		case vd of
-			Nothing -> return ()
-			Just vd' -> putStrLn $ "\t(" ++ vd' ++ ")"
+	let l = map mk (filter notinconfig $ remoteConfigFieldParsers cp)
+		++ map mk' (maybe [] snd (remoteConfigRestPassthrough cp))
+	liftIO $ forM_ l $ \(p, fd, vd) -> case fd of
+		HiddenField -> return ()
+		FieldDesc d -> do
+			putStrLn p
+			putStrLn ("\t" ++ d)
+			case vd of
+				Nothing -> return ()
+				Just (ValueDesc d') ->
+					putStrLn $ "\t(" ++ d' ++ ")"
 	next $ return True
   where
 	notinconfig fp = not (M.member (parserForField fp) c)
-	mk fp = case fieldDesc fp of
-		HiddenField -> Nothing
-		FieldDesc d -> Just
-			( fromProposedAccepted (parserForField fp)
-			, d
-			, case valueDesc fp of
-				Nothing -> Nothing
-				Just (ValueDesc vd) -> Just vd
-			)
+	mk fp = ( fromProposedAccepted (parserForField fp)
+		, fieldDesc fp
+		, valueDesc fp
+		)
+	mk' (k, v) = (k, v, Nothing)

Remote/External.hs

@@ -792,7 +792,10 @@ lenientRemoteConfigParser = addRemoteConfigParser specialRemoteConfigParsers $
 			, trueFalseParser readonlyField False
 				(FieldDesc "enable readonly mode")
 			]
-		, remoteConfigRestPassthrough = const True
+		, remoteConfigRestPassthrough = Just
+			( const True
+			, [("*", FieldDesc "all other parameters are passed to external special remote program")]
+			)
 		}
 
 {- When the remote supports LISTCONFIGS, only accept the ones it listed.
@@ -804,14 +807,14 @@ strictRemoteConfigParser external = listConfigs external >>= \case
 		let s = S.fromList (map fst l)
 		let listed f = S.member (fromProposedAccepted f) s
 		return $ lenientRemoteConfigParser
-			{ remoteConfigRestPassthrough = listed }
+			{ remoteConfigRestPassthrough = Just (listed, l) }
 
-listConfigs :: External -> Annex (Maybe [(Setting, Description)])
+listConfigs :: External -> Annex (Maybe [(Setting, FieldDesc)])
 listConfigs external = handleRequest external LISTCONFIGS Nothing (collect [])
   where
 	collect l req = case req of
 		CONFIG s d -> Just $ return $
-			GetNextMessage $ collect ((s, d) : l)
+			GetNextMessage $ collect ((s, FieldDesc d) : l)
 		CONFIGEND -> result (Just (reverse l))
 		UNSUPPORTED_REQUEST -> result Nothing
 		_ -> Nothing

Remote/Helper/Encryptable.hs

@@ -78,7 +78,7 @@ encryptionConfigs = S.fromList (map parserForField encryptionConfigParsers)
 parseEncryptionConfig :: RemoteConfig -> Either String ParsedRemoteConfig
 parseEncryptionConfig c = parseRemoteConfig
 	(M.restrictKeys c encryptionConfigs)
-	(RemoteConfigParser encryptionConfigParsers (const False))
+	(RemoteConfigParser encryptionConfigParsers Nothing)
 
 encryptionFieldParser :: RemoteConfigFieldParser
 encryptionFieldParser = RemoteConfigFieldParser

Remote/S3.hs

@@ -102,8 +102,13 @@ remote = specialRemoteType $ RemoteType
 			, optionalStringParser mungekeysField HiddenField
 			, optionalStringParser AWS.s3credsField HiddenField
 			]
-		, remoteConfigRestPassthrough = \f ->
-			isMetaHeader f || isArchiveMetaHeader f
+		, remoteConfigRestPassthrough = Just
+			( \f -> isMetaHeader f || isArchiveMetaHeader f
+			,
+				[ ("x-amz-meta-*", FieldDesc "http headers to add when storing on S3")
+				, ("x-archive-meta-*", FieldDesc "http headers to add when storing on Internet Archive")
+			  	]
+			)
 		}
 	, setup = s3Setup
 	, exportSupported = exportIsSupported

Types/RemoteConfig.hs

@@ -53,11 +53,11 @@ newtype ValueDesc = ValueDesc String
 
 data RemoteConfigParser = RemoteConfigParser
 	{ remoteConfigFieldParsers :: [RemoteConfigFieldParser]
-	, remoteConfigRestPassthrough :: RemoteConfigField -> Bool
+	, remoteConfigRestPassthrough :: Maybe (RemoteConfigField -> Bool, [(String, FieldDesc)])
 	}
 
 mkRemoteConfigParser :: Monad m => [RemoteConfigFieldParser] -> RemoteConfig -> m RemoteConfigParser
-mkRemoteConfigParser l _ = pure (RemoteConfigParser l (const False))
+mkRemoteConfigParser l _ = pure (RemoteConfigParser l Nothing)
 
 addRemoteConfigParser :: [RemoteConfigFieldParser] -> RemoteConfigParser -> RemoteConfigParser
 addRemoteConfigParser l rpc = rpc

doc/special_remotes/S3.mdwn

@@ -140,4 +140,9 @@ the S3 remote.
   then use the same bucket.
 
 * `x-amz-meta-*` are passed through as http headers when storing keys
-  in S3. see [the Internet Archive S3 interface documentation](https://archive.org/help/abouts3.txt) for example headers.
+  in S3.
+
+* `x-archive-meta-*` are passed through as http headers when storing keys
+  in the Internet Archive. See
+  [the Internet Archive S3 interface documentation](https://archive.org/help/abouts3.txt)
+  for example headers.

doc/todo/some_way_to_get_a_list_of_options_for_a_special_remote_of_a_given_type.mdwn

@@ -9,3 +9,9 @@ and indeed I get asked for e.g. encryption to be explicitly specified (why not t
 
 [[!meta author=yoh]]
 [[!tag projects/datalad]]
+
+> [[done]] as eg `git annex initremote type=rsync --describe-other-params`.
+> 
+> External special remotes that implement LISTCONFIGS can also be queried:
+> 
+> 	git annex inittype type=external externaltype=foo --describe-other-params