lib/db, lib/model: Allow needing invalid files (fixes #7474) (#7476)

lib/db/lowlevel.go

@@ -846,6 +846,10 @@ func (db *Lowlevel) getMetaAndCheck(folder string) (*metadataTracker, error) {
 	db.gcMut.RLock()
 	defer db.gcMut.RUnlock()
 
+	return db.getMetaAndCheckGCLocked(folder)
+}
+
+func (db *Lowlevel) getMetaAndCheckGCLocked(folder string) (*metadataTracker, error) {
 	fixed, err := db.checkLocalNeed([]byte(folder))
 	if err != nil {
 		return nil, fmt.Errorf("checking local need: %w", err)

lib/db/schemaupdater.go

@@ -21,7 +21,7 @@ import (
 // do not put restrictions on downgrades (e.g. for repairs after a bugfix).
 const (
 	dbVersion             = 14
-	dbMigrationVersion    = 15
+	dbMigrationVersion    = 16
 	dbMinSyncthingVersion = "v1.9.0"
 )
 
@@ -104,6 +104,7 @@ func (db *schemaUpdater) updateSchema() error {
 		{13, 13, "v1.7.0", db.updateSchemaTo13},
 		{14, 14, "v1.9.0", db.updateSchemaTo14},
 		{14, 15, "v1.9.0", db.migration15},
+		{14, 16, "v1.9.0", db.checkRepairMigration},
 	}
 
 	for _, m := range migrations {
@@ -782,6 +783,16 @@ func (db *schemaUpdater) migration15(_ int) error {
 	return nil
 }
 
+func (db *schemaUpdater) checkRepairMigration(_ int) error {
+	for _, folder := range db.ListFolders() {
+		_, err := db.getMetaAndCheckGCLocked(folder)
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
 func (db *schemaUpdater) rewriteGlobals(t readWriteTransaction) error {
 	it, err := t.NewPrefixIterator([]byte{KeyTypeGlobal})
 	if err != nil {

lib/db/set_test.go

@@ -469,9 +469,10 @@ func TestNeedWithInvalid(t *testing.T) {
 	}
 
 	expectedNeed := fileList{
-		protocol.FileInfo{Name: "b", Version: protocol.Vector{Counters: []protocol.Counter{{ID: myID, Value: 1001}}}, Blocks: genBlocks(2)},
-		protocol.FileInfo{Name: "c", Version: protocol.Vector{Counters: []protocol.Counter{{ID: myID, Value: 1002}}}, Blocks: genBlocks(7)},
-		protocol.FileInfo{Name: "d", Version: protocol.Vector{Counters: []protocol.Counter{{ID: myID, Value: 1003}}}, Blocks: genBlocks(7)},
+		remote0Have[0],
+		remote1Have[0],
+		remote0Have[2],
+		remote1Have[2],
 	}
 
 	replace(s, protocol.LocalDeviceID, localHave)

lib/db/transactions.go

@@ -762,10 +762,8 @@ func (t readWriteTransaction) updateLocalNeed(keyBuf, folder, name []byte, add b
 }
 
 func Need(global FileVersion, haveLocal bool, localVersion protocol.Vector) bool {
-	// We never need an invalid file or a file without a valid version (just
-	// another way of expressing "invalid", really, until we fix that
-	// part...).
-	if global.IsInvalid() || global.Version.IsEmpty() {
+	// We never need a file without a valid version.
+	if global.Version.IsEmpty() {
 		return false
 	}
 	// We don't need a deleted file if we don't have it.