Invert incremental flags, default to incremental (#2051)

## Description

Sets the default run behavior for exchange to use
incremental backups.  The cli feature flag for enabling exchange incrementals has been swapped for a toggle that disables incrementals, forcing a full backup

## Does this PR need a docs update or release note?

- [x] ✅ Yes, it's included

## Type of change

- [x] 🌻 Feature

## Issue(s)

* #1901

## Test Plan

- [x] ⚡ Unit test
- [x] 💚 E2E

CHANGELOG.md

@@ -7,6 +7,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased] (alpha)
 
+### Added
+
+- Incremental backup support for exchange is now enabled by default.
+
 ### Changed
 
 - The selectors Reduce() process will only include details that match the DiscreteOwner, if one is specified.

src/cli/backup/exchange.go

@@ -105,7 +105,7 @@ func addExchangeCommands(cmd *cobra.Command) *cobra.Command {
 	switch cmd.Use {
 	case createCommand:
 		c, fs = utils.AddCommand(cmd, exchangeCreateCmd())
-		options.AddFeatureFlags(cmd, options.ExchangeIncrementals())
+		options.AddFeatureToggle(cmd, options.DisableIncrementals())
 
 		c.Use = c.Use + " " + exchangeServiceCommandCreateUseSuffix
 		c.Example = exchangeServiceCommandCreateExamples

src/cli/options/options.go

@@ -19,8 +19,8 @@ func Control() control.Options {
 		opt.DisableMetrics = true
 	}
 
-	if exchangeIncrementals {
-		opt.EnabledFeatures.ExchangeIncrementals = true
+	if disableIncrementals {
+		opt.ToggleFeatures.DisableIncrementals = true
 	}
 
 	return opt
@@ -53,28 +53,28 @@ func AddGlobalOperationFlags(cmd *cobra.Command) {
 // Feature Flags
 // ---------------------------------------------------------------------------
 
-var exchangeIncrementals bool
+var disableIncrementals bool
 
 type exposeFeatureFlag func(*pflag.FlagSet)
 
-// AddFeatureFlags adds CLI flags for each exposed feature flags to the
+// AddFeatureToggle adds CLI flags for each exposed feature toggle to the
 // persistent flag set within the command.
-func AddFeatureFlags(cmd *cobra.Command, effs ...exposeFeatureFlag) {
+func AddFeatureToggle(cmd *cobra.Command, effs ...exposeFeatureFlag) {
 	fs := cmd.PersistentFlags()
 	for _, fflag := range effs {
 		fflag(fs)
 	}
 }
 
-// Adds the '--exchange-incrementals' cli flag which, when set, enables
-// incrementals data retrieval for exchange backups.
-func ExchangeIncrementals() func(*pflag.FlagSet) {
+// Adds the hidden '--no-incrementals' cli flag which, when set, disables
+// incremental backups.
+func DisableIncrementals() func(*pflag.FlagSet) {
 	return func(fs *pflag.FlagSet) {
 		fs.BoolVar(
-			&exchangeIncrementals,
-			"exchange-incrementals",
+			&disableIncrementals,
+			"disable-incrementals",
 			false,
-			"Enable incremental data retrieval in Exchange backups.")
-		cobra.CheckErr(fs.MarkHidden("exchange-incrementals"))
+			"Disable incremental data retrieval in backups.")
+		cobra.CheckErr(fs.MarkHidden("disable-incrementals"))
 	}
 }

src/internal/connector/exchange/service_iterators_test.go

@@ -644,11 +644,7 @@ func (suite *ServiceIteratorsSuite) TestFilterContainersAndFillCollections_incre
 				test.resolver,
 				allScope,
 				test.dps,
-				control.Options{
-					EnabledFeatures: control.FeatureFlags{
-						ExchangeIncrementals: true,
-					},
-				},
+				control.Options{},
 			)
 			assert.NoError(t, err)
 

src/internal/operations/backup.go

@@ -212,7 +212,7 @@ func (op *BackupOperation) Run(ctx context.Context) (err error) {
 // checker to see if conditions are correct for incremental backup behavior such as
 // retrieving metadata like delta tokens and previous paths.
 func useIncrementalBackup(sel selectors.Selector, opts control.Options) bool {
-	return opts.EnabledFeatures.ExchangeIncrementals && sel.Service == selectors.ServiceExchange
+	return !opts.ToggleFeatures.DisableIncrementals
 }
 
 // ---------------------------------------------------------------------------

src/internal/operations/backup_integration_test.go

@@ -52,7 +52,7 @@ func prepNewTestBackupOp(
 	ctx context.Context,
 	bus events.Eventer,
 	sel selectors.Selector,
-	featureFlags control.FeatureFlags,
+	featureToggles control.Toggles,
 ) (BackupOperation, account.Account, *kopia.Wrapper, *kopia.ModelStore, func()) {
 	//revive:enable:context-as-argument
 	acct := tester.NewM365Account(t)
@@ -90,7 +90,7 @@ func prepNewTestBackupOp(
 		ms.Close(ctx)
 	}
 
-	bo := newTestBackupOp(t, ctx, kw, ms, acct, sel, bus, featureFlags, closer)
+	bo := newTestBackupOp(t, ctx, kw, ms, acct, sel, bus, featureToggles, closer)
 
 	return bo, acct, kw, ms, closer
 }
@@ -109,7 +109,7 @@ func newTestBackupOp(
 	acct account.Account,
 	sel selectors.Selector,
 	bus events.Eventer,
-	featureFlags control.FeatureFlags,
+	featureToggles control.Toggles,
 	closer func(),
 ) BackupOperation {
 	//revive:enable:context-as-argument
@@ -118,7 +118,7 @@ func newTestBackupOp(
 		opts = control.Options{}
 	)
 
-	opts.EnabledFeatures = featureFlags
+	opts.ToggleFeatures = featureToggles
 
 	bo, err := NewBackupOperation(ctx, opts, kw, sw, acct, sel, bus)
 	if !assert.NoError(t, err) {
@@ -554,7 +554,7 @@ func (suite *BackupOpIntegrationSuite) TestBackup_Run_exchange() {
 			var (
 				mb  = evmock.NewBus()
 				sel = test.selector().Selector
-				ffs = control.FeatureFlags{ExchangeIncrementals: test.runIncremental}
+				ffs = control.Toggles{}
 			)
 
 			bo, acct, kw, ms, closer := prepNewTestBackupOp(t, ctx, mb, sel, ffs)
@@ -630,7 +630,7 @@ func (suite *BackupOpIntegrationSuite) TestBackup_Run_exchangeIncrementals() {
 	var (
 		t          = suite.T()
 		acct       = tester.NewM365Account(t)
-		ffs        = control.FeatureFlags{ExchangeIncrementals: true}
+		ffs        = control.Toggles{}
 		mb         = evmock.NewBus()
 		now        = common.Now()
 		users      = []string{suite.user}
@@ -1010,7 +1010,7 @@ func (suite *BackupOpIntegrationSuite) TestBackup_Run_oneDrive() {
 
 	sel.Include(sel.AllData())
 
-	bo, _, _, _, closer := prepNewTestBackupOp(t, ctx, mb, sel.Selector, control.FeatureFlags{})
+	bo, _, _, _, closer := prepNewTestBackupOp(t, ctx, mb, sel.Selector, control.Toggles{})
 	defer closer()
 
 	runAndCheckBackup(t, ctx, &bo, mb)
@@ -1032,7 +1032,7 @@ func (suite *BackupOpIntegrationSuite) TestBackup_Run_sharePoint() {
 
 	sel.Include(sel.AllData())
 
-	bo, _, _, _, closer := prepNewTestBackupOp(t, ctx, mb, sel.Selector, control.FeatureFlags{})
+	bo, _, _, _, closer := prepNewTestBackupOp(t, ctx, mb, sel.Selector, control.Toggles{})
 	defer closer()
 
 	runAndCheckBackup(t, ctx, &bo, mb)

src/pkg/control/options.go

@@ -9,14 +9,14 @@ type Options struct {
 	Collision      CollisionPolicy `json:"-"`
 	DisableMetrics bool            `json:"disableMetrics"`
 	FailFast       bool            `json:"failFast"`
-	EnabledFeatures FeatureFlags    `json:"enabledFeatures"`
+	ToggleFeatures Toggles         `json:"ToggleFeatures"`
 }
 
 // Defaults provides an Options with the default values set.
 func Defaults() Options {
 	return Options{
 		FailFast:       true,
-		EnabledFeatures: FeatureFlags{},
+		ToggleFeatures: Toggles{},
 	}
 }
 
@@ -63,11 +63,15 @@ func DefaultRestoreDestination(timeFormat common.TimeFormat) RestoreDestination
 }
 
 // ---------------------------------------------------------------------------
-// Feature Flags
+// Feature Flags and Toggles
 // ---------------------------------------------------------------------------
 
-type FeatureFlags struct {
-	// ExchangeIncrementals allow for re-use of delta links when backing up
-	// exchange data, reducing the amount of data pulled from graph.
-	ExchangeIncrementals bool `json:"incrementals,omitempty"`
+// Toggles allows callers to force corso to behave in ways that deviate from
+// the default expectations by turning on or shutting off certain features.
+// The default state for every toggle is false; toggles are only turned on
+// if specified by the caller.
+type Toggles struct {
+	// DisableIncrementals prevents backups from using incremental lookups,
+	// forcing a new, complete backup of all data regardless of prior state.
+	DisableIncrementals bool `json:"exchangeIncrementals,omitempty"`
 }