[bugfix] Add proper constraints on status faves, dedupe (#1674)

* [bugfix] Start working on multiple like issue

* finish up

4 files changed, 210 insertions, 86 deletions

diff --git a/internal/federation/federatingdb/create.go b/internal/federation/federatingdb/create.go
index 166ea34a9..b14a0597b 100644
--- a/internal/federation/federatingdb/create.go
+++ b/internal/federation/federatingdb/create.go
@@ -288,13 +288,19 @@ func (f *federatingDB) activityLike(ctx context.Context, asType vocab.Type, rece
 
 	fave, err := f.typeConverter.ASLikeToFave(ctx, like)
 	if err != nil {
-		return fmt.Errorf("activityLike: could not convert Like to fave: %s", err)
+		return fmt.Errorf("activityLike: could not convert Like to fave: %w", err)
 	}
 
 	fave.ID = id.NewULID()
 
-	if err := f.state.DB.Put(ctx, fave); err != nil {
-		return fmt.Errorf("activityLike: database error inserting fave: %s", err)
+	if err := f.state.DB.PutStatusFave(ctx, fave); err != nil {
+		if errors.Is(err, db.ErrAlreadyExists) {
+			// The Like already exists in the database, which
+			// means we've already handled side effects. We can
+			// just return nil here and be done with it.
+			return nil
+		}
+		return fmt.Errorf("activityLike: database error inserting fave: %w", err)
 	}
 
 	f.state.Workers.EnqueueFederator(ctx, messages.FromFederator{
diff --git a/internal/federation/federatingdb/owns.go b/internal/federation/federatingdb/owns.go
index 62cb7a3ea..cc3bb7d5d 100644
--- a/internal/federation/federatingdb/owns.go
+++ b/internal/federation/federatingdb/owns.go
@@ -19,12 +19,14 @@ package federatingdb
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"net/url"
 
 	"codeberg.org/gruf/go-kv"
 	"github.com/superseriousbusiness/gotosocial/internal/config"
 	"github.com/superseriousbusiness/gotosocial/internal/db"
+	"github.com/superseriousbusiness/gotosocial/internal/gtscontext"
 	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
 	"github.com/superseriousbusiness/gotosocial/internal/log"
 	"github.com/superseriousbusiness/gotosocial/internal/uris"
@@ -46,6 +48,11 @@ func (f *federatingDB) Owns(ctx context.Context, id *url.URL) (bool, error) {
 		return false, nil
 	}
 
+	// todo: refactor the below; make sure we use
+	// proper db functions for everything, and
+	// preferably clean up by calling subfuncs
+	// (like we now do for ownsLike).
+
 	// apparently it belongs to this host, so what *is* it?
 	// check if it's a status, eg /users/example_username/statuses/SOME_UUID_OF_A_STATUS
 	if uris.IsStatusesPath(id) {
@@ -117,28 +124,7 @@ func (f *federatingDB) Owns(ctx context.Context, id *url.URL) (bool, error) {
 	}
 
 	if uris.IsLikePath(id) {
-		username, likeID, err := uris.ParseLikedPath(id)
-		if err != nil {
-			return false, fmt.Errorf("error parsing like path for url %s: %s", id.String(), err)
-		}
-		if _, err := f.state.DB.GetAccountByUsernameDomain(ctx, username, ""); err != nil {
-			if err == db.ErrNoEntries {
-				// there are no entries for this username
-				return false, nil
-			}
-			// an actual error happened
-			return false, fmt.Errorf("database error fetching account with username %s: %s", username, err)
-		}
-		if err := f.state.DB.GetByID(ctx, likeID, &gtsmodel.StatusFave{}); err != nil {
-			if err == db.ErrNoEntries {
-				// there are no entries
-				return false, nil
-			}
-			// an actual error happened
-			return false, fmt.Errorf("database error fetching like with id %s: %s", likeID, err)
-		}
-		l.Debugf("we own url %s", id.String())
-		return true, nil
+		return f.ownsLike(ctx, id)
 	}
 
 	if uris.IsBlockPath(id) {
@@ -168,3 +154,39 @@ func (f *federatingDB) Owns(ctx context.Context, id *url.URL) (bool, error) {
 
 	return false, fmt.Errorf("could not match activityID: %s", id.String())
 }
+
+func (f *federatingDB) ownsLike(ctx context.Context, uri *url.URL) (bool, error) {
+	username, id, err := uris.ParseLikedPath(uri)
+	if err != nil {
+		return false, fmt.Errorf("error parsing Like path for url %s: %w", uri.String(), err)
+	}
+
+	// We're only checking for existence,
+	// so use barebones context.
+	bbCtx := gtscontext.SetBarebones(ctx)
+
+	if _, err := f.state.DB.GetAccountByUsernameDomain(bbCtx, username, ""); err != nil {
+		if errors.Is(err, db.ErrNoEntries) {
+			// No entries for this acct,
+			// we don't own this item.
+			return false, nil
+		}
+
+		// Actual error.
+		return false, fmt.Errorf("database error fetching account with username %s: %w", username, err)
+	}
+
+	if _, err := f.state.DB.GetStatusFaveByID(bbCtx, id); err != nil {
+		if errors.Is(err, db.ErrNoEntries) {
+			// No entries for this ID,
+			// we don't own this item.
+			return false, nil
+		}
+
+		// Actual error.
+		return false, fmt.Errorf("database error fetching status fave with id %s: %w", id, err)
+	}
+
+	log.Tracef(ctx, "we own Like %s", uri.String())
+	return true, nil
+}
diff --git a/internal/federation/federatingdb/undo.go b/internal/federation/federatingdb/undo.go
index 517aa9cc6..c17bd2e90 100644
--- a/internal/federation/federatingdb/undo.go
+++ b/internal/federation/federatingdb/undo.go
@@ -26,11 +26,13 @@ import (
 	"github.com/superseriousbusiness/activity/streams/vocab"
 	"github.com/superseriousbusiness/gotosocial/internal/ap"
 	"github.com/superseriousbusiness/gotosocial/internal/db"
+	"github.com/superseriousbusiness/gotosocial/internal/gtscontext"
+	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
 	"github.com/superseriousbusiness/gotosocial/internal/log"
 )
 
 func (f *federatingDB) Undo(ctx context.Context, undo vocab.ActivityStreamsUndo) error {
-	l := log.Entry{}.WithContext(ctx)
+	l := log.WithContext(ctx)
 
 	if log.Level() >= level.DEBUG {
 		i, err := marshalItem(undo)
@@ -55,70 +57,160 @@ func (f *federatingDB) Undo(ctx context.Context, undo vocab.ActivityStreamsUndo)
 	}
 
 	for iter := undoObject.Begin(); iter != undoObject.End(); iter = iter.Next() {
-		if iter.GetType() == nil {
+		t := iter.GetType()
+		if t == nil {
 			continue
 		}
-		switch iter.GetType().GetTypeName() {
+
+		switch t.GetTypeName() {
 		case ap.ActivityFollow:
-			// UNDO FOLLOW
-			ASFollow, ok := iter.GetType().(vocab.ActivityStreamsFollow)
-			if !ok {
-				return errors.New("UNDO: couldn't parse follow into vocab.ActivityStreamsFollow")
-			}
-			// make sure the actor owns the follow
-			if !sameActor(undo.GetActivityStreamsActor(), ASFollow.GetActivityStreamsActor()) {
-				return errors.New("UNDO: follow actor and activity actor not the same")
-			}
-			// convert the follow to something we can understand
-			gtsFollow, err := f.typeConverter.ASFollowToFollow(ctx, ASFollow)
-			if err != nil {
-				return fmt.Errorf("UNDO: error converting asfollow to gtsfollow: %s", err)
-			}
-			// make sure the addressee of the original follow is the same as whatever inbox this landed in
-			if gtsFollow.TargetAccountID != receivingAccount.ID {
-				return errors.New("UNDO: follow object account and inbox account were not the same")
+			if err := f.undoFollow(ctx, receivingAccount, undo, t); err != nil {
+				return err
 			}
-			// delete any existing FOLLOW
-			if err := f.state.DB.DeleteFollowByURI(ctx, gtsFollow.URI); err != nil && !errors.Is(err, db.ErrNoEntries) {
-				return fmt.Errorf("UNDO: db error removing follow: %s", err)
-			}
-			// delete any existing FOLLOW REQUEST
-			if err := f.state.DB.DeleteFollowRequestByURI(ctx, gtsFollow.URI); err != nil && !errors.Is(err, db.ErrNoEntries) {
-				return fmt.Errorf("UNDO: db error removing follow request: %s", err)
-			}
-			l.Debug("follow undone")
-			return nil
 		case ap.ActivityLike:
-			// UNDO LIKE
+			if err := f.undoLike(ctx, receivingAccount, undo, t); err != nil {
+				return err
+			}
 		case ap.ActivityAnnounce:
-			// UNDO BOOST/REBLOG/ANNOUNCE
+			// todo: undo boost / reblog / announce
 		case ap.ActivityBlock:
-			// UNDO BLOCK
-			ASBlock, ok := iter.GetType().(vocab.ActivityStreamsBlock)
-			if !ok {
-				return errors.New("UNDO: couldn't parse block into vocab.ActivityStreamsBlock")
+			if err := f.undoBlock(ctx, receivingAccount, undo, t); err != nil {
+				return err
 			}
-			// make sure the actor owns the follow
-			if !sameActor(undo.GetActivityStreamsActor(), ASBlock.GetActivityStreamsActor()) {
-				return errors.New("UNDO: block actor and activity actor not the same")
-			}
-			// convert the block to something we can understand
-			gtsBlock, err := f.typeConverter.ASBlockToBlock(ctx, ASBlock)
-			if err != nil {
-				return fmt.Errorf("UNDO: error converting asblock to gtsblock: %s", err)
-			}
-			// make sure the addressee of the original block is the same as whatever inbox this landed in
-			if gtsBlock.TargetAccountID != receivingAccount.ID {
-				return errors.New("UNDO: block object account and inbox account were not the same")
-			}
-			// delete any existing BLOCK
-			if err := f.state.DB.DeleteBlockByURI(ctx, gtsBlock.URI); err != nil {
-				return fmt.Errorf("UNDO: db error removing block: %s", err)
-			}
-			l.Debug("block undone")
+		}
+	}
+
+	return nil
+}
+
+func (f *federatingDB) undoFollow(
+	ctx context.Context,
+	receivingAccount *gtsmodel.Account,
+	undo vocab.ActivityStreamsUndo,
+	t vocab.Type,
+) error {
+	Follow, ok := t.(vocab.ActivityStreamsFollow)
+	if !ok {
+		return errors.New("undoFollow: couldn't parse vocab.Type into vocab.ActivityStreamsFollow")
+	}
+
+	// Make sure the undo actor owns the target.
+	if !sameActor(undo.GetActivityStreamsActor(), Follow.GetActivityStreamsActor()) {
+		// Ignore this Activity.
+		return nil
+	}
+
+	follow, err := f.typeConverter.ASFollowToFollow(ctx, Follow)
+	if err != nil {
+		return fmt.Errorf("undoFollow: error converting ActivityStreams Follow to follow: %w", err)
+	}
+
+	// Ensure addressee is follow target.
+	if follow.TargetAccountID != receivingAccount.ID {
+		// Ignore this Activity.
+		return nil
+	}
+
+	// Delete any existing follow with this URI.
+	if err := f.state.DB.DeleteFollowByURI(ctx, follow.URI); err != nil && !errors.Is(err, db.ErrNoEntries) {
+		return fmt.Errorf("undoFollow: db error removing follow: %w", err)
+	}
+
+	// Delete any existing follow request with this URI.
+	if err := f.state.DB.DeleteFollowRequestByURI(ctx, follow.URI); err != nil && !errors.Is(err, db.ErrNoEntries) {
+		return fmt.Errorf("undoFollow: db error removing follow request: %w", err)
+	}
+
+	log.Debug(ctx, "Follow undone")
+	return nil
+}
+
+func (f *federatingDB) undoLike(
+	ctx context.Context,
+	receivingAccount *gtsmodel.Account,
+	undo vocab.ActivityStreamsUndo,
+	t vocab.Type,
+) error {
+	Like, ok := t.(vocab.ActivityStreamsLike)
+	if !ok {
+		return errors.New("undoLike: couldn't parse vocab.Type into vocab.ActivityStreamsLike")
+	}
+
+	// Make sure the undo actor owns the target.
+	if !sameActor(undo.GetActivityStreamsActor(), Like.GetActivityStreamsActor()) {
+		// Ignore this Activity.
+		return nil
+	}
+
+	fave, err := f.typeConverter.ASLikeToFave(ctx, Like)
+	if err != nil {
+		return fmt.Errorf("undoLike: error converting ActivityStreams Like to fave: %w", err)
+	}
+
+	// Ensure addressee is fave target.
+	if fave.TargetAccountID != receivingAccount.ID {
+		// Ignore this Activity.
+		return nil
+	}
+
+	// Ignore URI on Likes, since we often get multiple Likes
+	// with the same target and account ID, but differing URIs.
+	// Instead, we'll select using account and target status.
+	// Regardless of the URI, we can read an Undo Like to mean
+	// "I don't want to fave this post anymore".
+	fave, err = f.state.DB.GetStatusFave(gtscontext.SetBarebones(ctx), fave.AccountID, fave.StatusID)
+	if err != nil {
+		if errors.Is(err, db.ErrNoEntries) {
+			// We didn't have a like/fave
+			// for this combo anyway, ignore.
 			return nil
 		}
+		// Real error.
+		return fmt.Errorf("undoLike: db error getting fave from %s targeting %s: %w", fave.AccountID, fave.StatusID, err)
+	}
+
+	// Delete the status fave.
+	if err := f.state.DB.DeleteStatusFaveByID(ctx, fave.ID); err != nil {
+		return fmt.Errorf("undoLike: db error deleting fave %s: %w", fave.ID, err)
+	}
+
+	log.Debug(ctx, "Like undone")
+	return nil
+}
+
+func (f *federatingDB) undoBlock(
+	ctx context.Context,
+	receivingAccount *gtsmodel.Account,
+	undo vocab.ActivityStreamsUndo,
+	t vocab.Type,
+) error {
+	Block, ok := t.(vocab.ActivityStreamsBlock)
+	if !ok {
+		return errors.New("undoBlock: couldn't parse vocab.Type into vocab.ActivityStreamsBlock")
+	}
+
+	// Make sure the undo actor owns the target.
+	if !sameActor(undo.GetActivityStreamsActor(), Block.GetActivityStreamsActor()) {
+		// Ignore this Activity.
+		return nil
+	}
+
+	block, err := f.typeConverter.ASBlockToBlock(ctx, Block)
+	if err != nil {
+		return fmt.Errorf("undoBlock: error converting ActivityStreams Block to block: %w", err)
+	}
+
+	// Ensure addressee is block target.
+	if block.TargetAccountID != receivingAccount.ID {
+		// Ignore this Activity.
+		return nil
+	}
+
+	// Delete any existing BLOCK
+	if err := f.state.DB.DeleteBlockByURI(ctx, block.URI); err != nil && !errors.Is(err, db.ErrNoEntries) {
+		return fmt.Errorf("undoBlock: db error removing block: %w", err)
 	}
 
+	log.Debug(ctx, "Block undone")
 	return nil
 }
diff --git a/internal/federation/federatingdb/util.go b/internal/federation/federatingdb/util.go
index 8ad209f5e..5137145f2 100644
--- a/internal/federation/federatingdb/util.go
+++ b/internal/federation/federatingdb/util.go
@@ -36,23 +36,27 @@ import (
 	"github.com/superseriousbusiness/gotosocial/internal/uris"
 )
 
-func sameActor(activityActor vocab.ActivityStreamsActorProperty, followActor vocab.ActivityStreamsActorProperty) bool {
-	if activityActor == nil || followActor == nil {
+func sameActor(actor1 vocab.ActivityStreamsActorProperty, actor2 vocab.ActivityStreamsActorProperty) bool {
+	if actor1 == nil || actor2 == nil {
 		return false
 	}
-	for aIter := activityActor.Begin(); aIter != activityActor.End(); aIter = aIter.Next() {
-		for fIter := followActor.Begin(); fIter != followActor.End(); fIter = fIter.Next() {
-			if aIter.GetIRI() == nil {
+
+	for a1Iter := actor1.Begin(); a1Iter != actor1.End(); a1Iter = a1Iter.Next() {
+		for a2Iter := actor2.Begin(); a2Iter != actor2.End(); a2Iter = a2Iter.Next() {
+			if a1Iter.GetIRI() == nil {
 				return false
 			}
-			if fIter.GetIRI() == nil {
+
+			if a2Iter.GetIRI() == nil {
 				return false
 			}
-			if aIter.GetIRI().String() == fIter.GetIRI().String() {
+
+			if a1Iter.GetIRI().String() == a2Iter.GetIRI().String() {
 				return true
 			}
 		}
 	}
+
 	return false
 }