lib/db: Update global meta even if unchanged (fixes #6850) (#6852)

lib/db/set_test.go

@@ -1707,6 +1707,38 @@ func TestNeedRemoteAfterReset(t *testing.T) {
 	}
 }
 
+// https://github.com/syncthing/syncthing/issues/6850
+func TestIgnoreLocalChanged(t *testing.T) {
+	ldb := db.NewLowlevel(backend.OpenMemory())
+	defer ldb.Close()
+
+	s := db.NewFileSet("test", fs.NewFilesystem(fs.FilesystemTypeFake, ""), ldb)
+
+	// Add locally changed file
+	files := fileList{
+		protocol.FileInfo{Name: "b", Version: protocol.Vector{Counters: []protocol.Counter{{ID: myID, Value: 1001}}}, Blocks: genBlocks(2), LocalFlags: protocol.FlagLocalReceiveOnly},
+	}
+	s.Update(protocol.LocalDeviceID, files)
+
+	if c := globalSize(s).Files; c != 1 {
+		t.Error("Expected one global file, got", c)
+	}
+	if c := localSize(s).Files; c != 1 {
+		t.Error("Expected one local file, got", c)
+	}
+
+	// Change file to ignored
+	files[0].LocalFlags = protocol.FlagLocalIgnored
+	s.Update(protocol.LocalDeviceID, files)
+
+	if c := globalSize(s).Files; c != 0 {
+		t.Error("Expected no global file, got", c)
+	}
+	if c := localSize(s).Files; c != 0 {
+		t.Error("Expected no local file, got", c)
+	}
+}
+
 func replace(fs *db.FileSet, device protocol.DeviceID, files []protocol.FileInfo) {
 	fs.Drop(device)
 	fs.Update(device, files)

lib/db/transactions.go

@@ -662,13 +662,11 @@ func (t readWriteTransaction) updateGlobal(gk, keyBuf, folder, device []byte, fi
 		}
 	}
 
-	// Update global size counter if necessary
-
-	if !globalChanged {
-		// Neither the global state nor the needs of any devices, except
-		// the one updated, changed.
-		return keyBuf, true, nil
-	}
+	// Update global size counter.
+	// It's done regardless of if the global changed, as two files might
+	// both be invalid, but for different reasons i.e. have different flags
+	// (e.g. ignored vs receive only).
+	// https://github.com/syncthing/syncthing/issues/6850
 
 	// Remove the old global from the global size counter
 	if haveOldGlobal {
@@ -691,6 +689,12 @@ func (t readWriteTransaction) updateGlobal(gk, keyBuf, folder, device []byte, fi
 	}
 	meta.addFile(protocol.GlobalDeviceID, global)
 
+	if !globalChanged {
+		// Neither the global state nor the needs of any devices, except
+		// the one updated, changed.
+		return keyBuf, true, nil
+	}
+
 	// check for local (if not already done before)
 	if !bytes.Equal(device, protocol.LocalDeviceID[:]) {
 		localFV, haveLocal := fl.Get(protocol.LocalDeviceID[:])