sync --no-content import from directory special remote

sync: When run without --content, import without copying from
importtree=yes directory special remotes. (Other special remotes may
support this later as well.)

This commit was sponsored by Svenne Krap on Patreon.

Annex/Import.hs

@@ -12,6 +12,7 @@ module Annex.Import (
 	ImportCommitConfig(..),
 	buildImportCommit,
 	buildImportTrees,
+	canImportKeys,
 	importKeys,
 	filterImportableContents,
 	makeImportMatcher,
@@ -281,6 +282,12 @@ buildImportTrees basetree msubdir importable = History
 		topf = asTopFilePath $
 			maybe lf (\sd -> getTopFilePath sd P.</> lf) msubdir
 
+canImportKeys :: Remote -> Bool -> Bool
+canImportKeys remote importcontent =
+	importcontent || isJust (Remote.importKey ia)
+  where
+	ia = Remote.importActions remote
+
 {- Downloads all new ContentIdentifiers, or when importcontent is False,
  - generates Keys without downloading.
  -
@@ -304,7 +311,7 @@ importKeys
 	-> ImportableContents (ContentIdentifier, ByteSize)
 	-> Annex (Maybe (ImportableContents (Either Sha Key)))
 importKeys remote importtreeconfig importcontent importablecontents = do
-	when (not importcontent && isNothing (Remote.importKey ia)) $
+	unless (canImportKeys remote importcontent) $
 		giveup "This remote does not support importing without downloading content."
 	-- This map is used to remember content identifiers that
 	-- were just imported, before they have necessarily been

CHANGELOG

@@ -27,6 +27,9 @@ git-annex (8.20200909) UNRELEASED; urgency=medium
     files into git, the same as is done when importing with content.
     If the largefiles expression needs the file content available
     (due to mimetype or mimeencoding being used), the import will fail.
+  * sync: When run without --content, import without copying from
+    importtree=yes directory special remotes.
+    (Other special remotes may support this later as well.)
 
  -- Joey Hess <id@joeyh.name>  Mon, 14 Sep 2020 18:34:37 -0400
 

Command/Sync.hs

@@ -66,6 +66,7 @@ import Annex.UpdateInstead
 import Annex.Export
 import Annex.TaggedPush
 import Annex.CurrentBranch
+import Annex.Import (canImportKeys)
 import Types.FileMatcher
 import qualified Database.Export as Export
 import Utility.Bloom
@@ -468,8 +469,11 @@ importRemote importcontent o mergeconfig remote currbranch
 			let subdir = if S.null p
 				then Nothing
 				else Just (asTopFilePath p)
+			if canImportKeys remote importcontent
+				then do
 					Command.Import.seekRemote remote branch subdir importcontent
 					void $ mergeRemote remote currbranch mergeconfig o
+				else warning $ "Cannot import from " ++ Remote.name remote ++ " when not syncing content."
   where
 	wantpull = remoteAnnexPull (Remote.gitconfig remote)