Allow limiting max conflicts (fixes #2282)

gui/syncthing/core/syncthingController.js

@@ -1135,6 +1135,7 @@ angular.module('syncthing.core')
             };
             $scope.currentFolder.rescanIntervalS = 60;
             $scope.currentFolder.minDiskFreePct = 1;
+            $scope.currentFolder.maxConflicts = -1;
             $scope.currentFolder.order = "random";
             $scope.currentFolder.fileVersioningSelector = "none";
             $scope.currentFolder.trashcanClean = 0;
@@ -1156,6 +1157,7 @@ angular.module('syncthing.core')
                 selectedDevices: {},
                 rescanIntervalS: 60,
                 minDiskFreePct: 1,
+                maxConflicts: -1,
                 order: "random",
                 fileVersioningSelector: "none",
                 trashcanClean: 0,

lib/config/config.go

@@ -111,6 +111,7 @@ type FolderConfiguration struct {
 	ScanProgressIntervalS int                         `xml:"scanProgressIntervalS" json:"scanProgressIntervalS"` // Set to a negative value to disable. Value of 0 will get replaced with value of 2 (default value)
 	PullerSleepS          int                         `xml:"pullerSleepS" json:"pullerSleepS"`
 	PullerPauseS          int                         `xml:"pullerPauseS" json:"pullerPauseS"`
+	MaxConflicts          int                         `xml:"maxConflicts" json:"maxConflicts"`
 
 	Invalid string `xml:"-" json:"invalid"` // Set at runtime when there is an error, not saved
 }
@@ -499,14 +500,6 @@ func ChangeRequiresRestart(from, to Configuration) bool {
 	return false
 }
 
-func convertV10V11(cfg *Configuration) {
-	// Set minimum disk free of existing folders to 1%
-	for i := range cfg.Folders {
-		cfg.Folders[i].MinDiskFreePct = 1
-	}
-	cfg.Version = 11
-}
-
 func convertV11V12(cfg *Configuration) {
 	// Change listen address schema
 	for i, addr := range cfg.Options.ListenAddress {
@@ -550,9 +543,22 @@ func convertV11V12(cfg *Configuration) {
 		cfg.Options.LocalAnnPort = 21027
 	}
 
+	// Set MaxConflicts to unlimited
+	for i := range cfg.Folders {
+		cfg.Folders[i].MaxConflicts = -1
+	}
+
 	cfg.Version = 12
 }
 
+func convertV10V11(cfg *Configuration) {
+	// Set minimum disk free of existing folders to 1%
+	for i := range cfg.Folders {
+		cfg.Folders[i].MinDiskFreePct = 1
+	}
+	cfg.Version = 11
+}
+
 func convertV9V10(cfg *Configuration) {
 	// Enable auto normalization on existing folders.
 	for i := range cfg.Folders {

lib/config/config_test.go

@@ -100,6 +100,7 @@ func TestDeviceConfig(t *testing.T) {
 				Hashers:         0,
 				AutoNormalize:   true,
 				MinDiskFreePct:  1,
+				MaxConflicts:    -1,
 			},
 		}
 		expectedDevices := []DeviceConfiguration{

lib/config/testdata/v12.xml

@@ -3,6 +3,7 @@
         <device id="AIR6LPZ-7K4PTTV-UXQSMUU-CPQ5YWH-OEDFIIQ-JUG777G-2YQXXR5-YD6AWQR"></device>
         <device id="P56IOI7-MZJNU2Y-IQGDREY-DM2MGTI-MGL3BXN-PQ6W5BM-TBBZ4TJ-XZWICQ2"></device>
         <minDiskFreePct>1</minDiskFreePct>
+        <maxConflicts>-1</maxConflicts>
     </folder>
     <device id="AIR6LPZ-7K4PTTV-UXQSMUU-CPQ5YWH-OEDFIIQ-JUG777G-2YQXXR5-YD6AWQR" name="node one" compression="metadata">
         <address>tcp://a</address>

lib/model/rwfolder.go

@@ -88,6 +88,7 @@ type rwFolder struct {
 	pullers      int
 	shortID      uint64
 	order        config.PullOrder
+	maxConflicts int
 	sleep        time.Duration
 	pause        time.Duration
 
@@ -123,6 +124,7 @@ func newRWFolder(m *Model, shortID uint64, cfg config.FolderConfiguration) *rwFo
 		pullers:      cfg.Pullers,
 		shortID:      shortID,
 		order:        cfg.Order,
+		maxConflicts: cfg.MaxConflicts,
 
 		stop:        make(chan struct{}),
 		queue:       newJobQueue(),
@@ -757,7 +759,7 @@ func (p *rwFolder) deleteFile(file protocol.FileInfo) {
 		// of deleting. Also merge with the version vector we had, to indicate
 		// we have resolved the conflict.
 		file.Version = file.Version.Merge(cur.Version)
-		err = osutil.InWritableDir(moveForConflict, realName)
+		err = osutil.InWritableDir(p.moveForConflict, realName)
 	} else if p.versioner != nil {
 		err = osutil.InWritableDir(p.versioner.Archive, realName)
 	} else {
@@ -1254,7 +1256,7 @@ func (p *rwFolder) performFinish(state *sharedPullerState) error {
 			// we have resolved the conflict.
 
 			state.file.Version = state.file.Version.Merge(state.version)
-			if err = osutil.InWritableDir(moveForConflict, state.realName); err != nil {
+			if err = osutil.InWritableDir(p.moveForConflict, state.realName); err != nil {
 				return err
 			}
 
@@ -1447,7 +1449,14 @@ func removeDevice(devices []protocol.DeviceID, device protocol.DeviceID) []proto
 	return devices
 }
 
-func moveForConflict(name string) error {
+func (p *rwFolder) moveForConflict(name string) error {
+	if p.maxConflicts == 0 {
+		if err := osutil.Remove(name); err != nil && !os.IsNotExist(err) {
+			return err
+		}
+		return nil
+	}
+
 	ext := filepath.Ext(name)
 	withoutExt := name[:len(name)-len(ext)]
 	newName := withoutExt + time.Now().Format(".sync-conflict-20060102-150405") + ext
@@ -1457,7 +1466,21 @@ func moveForConflict(name string) error {
 		// the user has already moved it away, or the conflict was between a
 		// remote modification and a local delete. In either way it does not
 		// matter, go ahead as if the move succeeded.
-		return nil
+		err = nil
+	}
+	if p.maxConflicts > -1 {
+		matches, gerr := osutil.Glob(withoutExt + ".sync-conflict-????????-??????" + ext)
+		if gerr == nil && len(matches) > p.maxConflicts {
+			sort.Sort(sort.Reverse(sort.StringSlice(matches)))
+			for _, match := range matches[p.maxConflicts:] {
+				gerr = osutil.Remove(match)
+				if gerr != nil {
+					l.Debugln(p, "removing extra conflict", gerr)
+				}
+			}
+		} else if gerr != nil {
+			l.Debugln(p, "globbing for conflicts", gerr)
+		}
 	}
 	return err
 }