[bugfix] Prevent multiple mentions being created for one mention (#4127)

# Description

> If this is a code change, please include a summary of what you've coded, and link to the issue(s) it closes/implements.
>
> If this is a documentation change, please briefly describe what you've changed and why.

This pull request fixes an issue where multiple mentions were being created for one statuses, when delivered to multiple inboxes on an instance, but only the final mention ended up actually being used. Also adds tests to make sure that a notification is received when a status is edited to include a mention.

## Checklist

Please put an x inside each checkbox to indicate that you've read and followed it: `[ ]` -> `[x]`

If this is a documentation change, only the first checkbox must be filled (you can delete the others if you want).

- [x] I/we have read the [GoToSocial contribution guidelines](https://codeberg.org/superseriousbusiness/gotosocial/src/branch/main/CONTRIBUTING.md).
- [x] I/we have discussed the proposed changes already, either in an issue on the repository, or in the Matrix chat.
- [x] I/we have not leveraged AI to create the proposed changes.
- [x] I/we have performed a self-review of added code.
- [x] I/we have written code that is legible and maintainable by others.
- [x] I/we have commented the added code, particularly in hard-to-understand areas.
- [ ] I/we have made any necessary changes to documentation.
- [x] I/we have added tests that cover new code.
- [x] I/we have run tests and they pass locally with the changes.
- [x] I/we have run `go fmt ./...` and `golangci-lint run`.

Reviewed-on: https://codeberg.org/superseriousbusiness/gotosocial/pulls/4127
Co-authored-by: tobi <tobi.smethurst@protonmail.com>
Co-committed-by: tobi <tobi.smethurst@protonmail.com>

internal/federation/dereferencing/status.go

@@ -670,9 +670,9 @@ func (d *Dereferencer) fetchStatusMentions(
 			alreadyExists bool
 		)
 
-		// Search existing status for a mention already stored,
+		// Search existing status + db for a mention already stored,
 		// else ensure new mention's target account is populated.
-		mention, alreadyExists, err = d.populateMentionTarget(ctx,
+		mention, alreadyExists, err = d.newOrExistingMention(ctx,
 			requestUser,
 			existing,
 			mention,
@@ -683,8 +683,8 @@ func (d *Dereferencer) fetchStatusMentions(
 		}
 
 		if alreadyExists {
-			// This mention was already attached
-			// to the status, use it and continue.
+			// This mention was already
+			// stored, use it and continue.
 			status.Mentions[i] = mention
 			status.MentionIDs[i] = mention.ID
 			continue
@@ -1294,14 +1294,15 @@ func (d *Dereferencer) handleStatusEdit(
 	return cols, nil
 }
 
-// populateMentionTarget tries to populate the given
+// newOrExistingMention tries to populate the given
 // mention with the correct TargetAccount and (if not
 // yet set) TargetAccountURI, returning the populated
 // mention.
 //
-// Will check on the existing status if the mention
-// is already there and populated; if so, existing
-// mention will be returned along with `true`.
+// Will check on the existing status and in the db
+// if the mention is already there and populated;
+// if so, existing mention will be returned along
+// with `true` to indicate that it already existed.
 //
 // Otherwise, this function will try to parse first
 // the Href of the mention, and then the namestring,
@@ -1312,7 +1313,7 @@ func (d *Dereferencer) handleStatusEdit(
 // rather than a URI, but because some remotes do
 // silly things like only provide `@username` instead
 // of `@username@domain`, we try by URI first.
-func (d *Dereferencer) populateMentionTarget(
+func (d *Dereferencer) newOrExistingMention(
 	ctx context.Context,
 	requestUser string,
 	existing *gtsmodel.Status,
@@ -1325,11 +1326,13 @@ func (d *Dereferencer) populateMentionTarget(
 	// Mentions can be created using `name` or `href`.
 	//
 	// Prefer `href` (TargetAccountURI), fall back to Name.
-	if mention.TargetAccountURI != "" {
-
-		// Look for existing mention with target account's URI, if so use this.
+	switch {
+	case mention.TargetAccountURI != "":
+		// Look on the status for existing mention with target account's URI.
 		existingMention, ok := existing.GetMentionByTargetURI(mention.TargetAccountURI)
 		if ok && existingMention.ID != "" {
+			// Already populated
+			// mention, use this.
 			return existingMention, true, nil
 		}
 
@@ -1354,8 +1357,25 @@ func (d *Dereferencer) populateMentionTarget(
 			err := gtserror.Newf("failed to dereference account %s: %w", targetAccountURI, err)
 			return nil, false, err
 		}
-	} else {
 
+		// Look in the db for this existing mention.
+		existingMention, err = d.state.DB.GetMentionByTargetAcctStatus(
+			ctx,
+			mention.TargetAccount.ID,
+			existing.ID,
+		)
+		if err != nil && !errors.Is(err, db.ErrNoEntries) {
+			err := gtserror.Newf("db error looking for existing mention: %w", err)
+			return nil, false, err
+		}
+
+		if existingMention != nil {
+			// Already had stored
+			// mention, use this.
+			return existingMention, true, nil
+		}
+
+	case mention.NameString != "":
 		// Href wasn't set, extract the username and domain parts from namestring.
 		username, domain, err := util.ExtractNamestringParts(mention.NameString)
 		if err != nil {
@@ -1363,9 +1383,11 @@ func (d *Dereferencer) populateMentionTarget(
 			return nil, false, err
 		}
 
-		// Look for existing mention with username domain target, if so use this.
+		// Look on the status for existing mention with username domain target.
 		existingMention, ok := existing.GetMentionByUsernameDomain(username, domain)
 		if ok && existingMention.ID != "" {
+			// Already populated
+			// mention, use this.
 			return existingMention, true, nil
 		}
 
@@ -1395,11 +1417,34 @@ func (d *Dereferencer) populateMentionTarget(
 			return nil, false, err
 		}
 
-		// Look for existing mention with target account's URI, if so use this.
+		// Look on the status for existing mention with target account's URI.
 		existingMention, ok = existing.GetMentionByTargetURI(mention.TargetAccountURI)
 		if ok && existingMention.ID != "" {
+			// Already populated
+			// mention, use this.
 			return existingMention, true, nil
 		}
+
+		// Look in the db for this existing mention.
+		existingMention, err = d.state.DB.GetMentionByTargetAcctStatus(
+			ctx,
+			mention.TargetAccount.ID,
+			existing.ID,
+		)
+		if err != nil && !errors.Is(err, db.ErrNoEntries) {
+			err := gtserror.Newf("db error looking for existing mention: %w", err)
+			return nil, false, err
+		}
+
+		if existingMention != nil {
+			// Already had stored
+			// mention, use this.
+			return existingMention, true, nil
+		}
+
+	default:
+		const errText = "neither target uri nor namestring were set on mention, cannot process it"
+		return nil, false, gtserror.New(errText)
 	}
 
 	// At this point, mention.TargetAccountURI

internal/federation/federatingdb/update_test.go

@@ -0,0 +1,76 @@
+// GoToSocial
+// Copyright (C) GoToSocial Authors admin@gotosocial.org
+// SPDX-License-Identifier: AGPL-3.0-or-later
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package federatingdb_test
+
+import (
+	"context"
+	"encoding/json"
+	"testing"
+	"time"
+
+	"code.superseriousbusiness.org/gotosocial/internal/ap"
+	"code.superseriousbusiness.org/gotosocial/internal/gtscontext"
+	"github.com/stretchr/testify/suite"
+)
+
+type UpdateTestSuite struct {
+	FederatingDBTestSuite
+}
+
+func (suite *UpdateTestSuite) TestUpdateNewMention() {
+	var (
+		ctx            = context.Background()
+		update         = suite.testActivities["remote_account_2_status_1_update"]
+		receivingAcct  = suite.testAccounts["local_account_1"]
+		requestingAcct = suite.testAccounts["remote_account_2"]
+	)
+
+	ctx = gtscontext.SetReceivingAccount(ctx, receivingAcct)
+	ctx = gtscontext.SetRequestingAccount(ctx, requestingAcct)
+
+	m, err := ap.Serialize(update.Activity)
+	if err != nil {
+		suite.FailNow(err.Error())
+	}
+
+	b, err := json.MarshalIndent(&m, "", "  ")
+	if err != nil {
+		suite.FailNow(err.Error())
+	}
+
+	suite.T().Logf("Update:\n%s\n", string(b))
+
+	note := update.Activity.GetActivityStreamsObject().At(0).GetActivityStreamsNote()
+	if err := suite.federatingDB.Update(ctx, note); err != nil {
+		suite.FailNow(err.Error())
+	}
+
+	// Should be a message heading to the processor.
+	msg, ok := suite.getFederatorMsg(5 * time.Second)
+	if !ok {
+		suite.FailNow("no federator message after 5s")
+	}
+
+	suite.Equal(ap.ObjectNote, msg.APObjectType)
+	suite.Equal(ap.ActivityUpdate, msg.APActivityType)
+	suite.NotNil(msg.APObject)
+}
+
+func TestUpdateTestSuite(t *testing.T) {
+	suite.Run(t, new(UpdateTestSuite))
+}

internal/processing/workers/fromfediapi.go

@@ -991,11 +991,6 @@ func (p *fediAPI) UpdateStatus(ctx context.Context, fMsg *messages.FromFediAPI)
 		}
 	}
 
-	// Push message that the status has been edited to streams.
-	if err := p.surface.timelineStatusUpdate(ctx, status); err != nil {
-		log.Errorf(ctx, "error streaming status edit: %v", err)
-	}
-
 	// Notify any *new* mentions added
 	// to this status by the editor.
 	for _, mention := range status.Mentions {
@@ -1015,6 +1010,11 @@ func (p *fediAPI) UpdateStatus(ctx context.Context, fMsg *messages.FromFediAPI)
 		}
 	}
 
+	// Push message that the status has been edited to streams.
+	if err := p.surface.timelineStatusUpdate(ctx, status); err != nil {
+		log.Errorf(ctx, "error streaming status edit: %v", err)
+	}
+
 	// Status representation changed, uncache from timelines.
 	p.surface.invalidateStatusFromTimelines(status.ID)
 

internal/processing/workers/fromfediapi_test.go

@@ -735,6 +735,52 @@ func (suite *FromFediAPITestSuite) TestUndoAnnounce() {
 	}
 }
 
+func (suite *FromFediAPITestSuite) TestUpdateNote() {
+	var (
+		ctx            = context.Background()
+		testStructs    = testrig.SetupTestStructs(rMediaPath, rTemplatePath)
+		requestingAcct = suite.testAccounts["remote_account_2"]
+		receivingAcct  = suite.testAccounts["local_account_1"]
+	)
+	defer testrig.TearDownTestStructs(testStructs)
+
+	update := testrig.NewTestActivities(suite.testAccounts)["remote_account_2_status_1_update"]
+	statusable := update.Activity.GetActivityStreamsObject().At(0).GetActivityStreamsNote()
+	noteURI := ap.GetJSONLDId(statusable)
+
+	// Get the OG status.
+	status, err := testStructs.State.DB.GetStatusByURI(ctx, noteURI.String())
+	if err != nil {
+		suite.FailNow(err.Error())
+	}
+
+	// Process the Update.
+	err = testStructs.Processor.Workers().ProcessFromFediAPI(ctx, &messages.FromFediAPI{
+		APObjectType:   ap.ObjectNote,
+		APActivityType: ap.ActivityUpdate,
+		GTSModel:       status, // original status
+		APObject:       (ap.Statusable)(statusable),
+		Receiving:      receivingAcct,
+		Requesting:     requestingAcct,
+	})
+	suite.NoError(err)
+
+	// Wait for side effects to trigger:
+	// zork should have a mention notif.
+	if !testrig.WaitFor(func() bool {
+		_, err := testStructs.State.DB.GetNotification(
+			gtscontext.SetBarebones(ctx),
+			gtsmodel.NotificationMention,
+			receivingAcct.ID,
+			requestingAcct.ID,
+			status.ID,
+		)
+		return err == nil
+	}) {
+		suite.FailNow("timed out waiting for mention notif")
+	}
+}
+
 func TestFromFederatorTestSuite(t *testing.T) {
 	suite.Run(t, &FromFediAPITestSuite{})
 }

testrig/testmodels.go

@@ -3514,6 +3514,49 @@ func NewTestActivities(accounts map[string]*gtsmodel.Account) map[string]Activit
 	keyToSignDelete := accounts["remote_account_1"].PrivateKey
 	deleteForRemoteAccount3Sig, deleteForRemoteAccount3Digest, deleteForRemoteAccount3Date := GetSignatureForActivity(deleteForRemoteAccount3, "https://somewhere.mysterious/users/rest_in_piss#main-key", keyToSignDelete, URLMustParse(accounts["local_account_1"].InboxURI))
 
+	remoteAccount2Status1Updated := NewAPNote(
+		URLMustParse("http://example.org/users/Some_User/statuses/01HE7XJ1CG84TBKH5V9XKBVGF5"),
+		URLMustParse("http://example.org/@Some_User/statuses/01HE7XJ1CG84TBKH5V9XKBVGF5"),
+		TimeMustParse("2023-11-02T12:44:25+02:00"),
+		`<p>hi <span class="h-card"><a href="http://localhost:8080/@admin" class="u-url mention" rel="nofollow noreferrer noopener" target="_blank">@<span>admin</span></a></span> here's some media for ya, <span class="h-card"><a href="http://localhost:8080/@the_mighty_zork" class="u-url mention" rel="nofollow noreferrer noopener" target="_blank">@<span>the_mighty_zork</span></a></span> you might like this too</p>`,
+		"<p>some unknown media included</p>",
+		URLMustParse("http://example.org/users/Some_User"),
+		[]*url.URL{
+			ap.PublicURI(),
+		},
+		[]*url.URL{
+			URLMustParse("http://example.org/users/Some_User/followers"),
+			URLMustParse("http://localhost:8080/users/admin"),
+			URLMustParse("http://localhost:8080/users/the_mighty_zork"),
+		},
+		true,
+		[]vocab.ActivityStreamsMention{
+			newAPMention(
+				URLMustParse("http://localhost:8080/users/admin"),
+				"@admin@localhost:8080",
+			),
+			newAPMention(
+				URLMustParse("http://localhost:8080/users/the_mighty_zork"),
+				"@the_mighty_zork@localhost:8080",
+			),
+		},
+		nil,
+		nil,
+	)
+	update := WrapAPNoteInUpdate(
+		URLMustParse("http://example.org/users/Some_User/statuses/01HE7XJ1CG84TBKH5V9XKBVGF5/update1"),
+		URLMustParse("http://example.org/users/Some_User/statuses/01HE7XJ1CG84TBKH5V9XKBVGF5"),
+		URLMustParse("http://example.org/users/Some_User"),
+		TimeMustParse("2023-11-02T12:46:25+02:00"),
+		remoteAccount2Status1Updated,
+	)
+	updateSig, updateDigest, updateDate := GetSignatureForActivity(
+		update,
+		accounts["remote_account_2"].PublicKeyURI,
+		accounts["remote_account_2"].PrivateKey,
+		URLMustParse(accounts["local_account_1"].InboxURI),
+	)
+
 	return map[string]ActivityWithSignature{
 		"dm_for_zork": {
 			Activity:        createDmForZork,
@@ -3563,6 +3606,12 @@ func NewTestActivities(accounts map[string]*gtsmodel.Account) map[string]Activit
 			DigestHeader:    deleteForRemoteAccount3Digest,
 			DateHeader:      deleteForRemoteAccount3Date,
 		},
+		"remote_account_2_status_1_update": {
+			Activity:        update,
+			SignatureHeader: updateSig,
+			DigestHeader:    updateDigest,
+			DateHeader:      updateDate,
+		},
 	}
 }
 
@@ -5186,6 +5235,27 @@ func WrapAPNoteInCreate(createID *url.URL, createActor *url.URL, createPublished
 	return create
 }
 
+func WrapAPNoteInUpdate(
+	updateID *url.URL,
+	updateTarget *url.URL,
+	updateActor *url.URL,
+	updatePublished time.Time,
+	updateNote vocab.ActivityStreamsNote,
+) vocab.ActivityStreamsUpdate {
+	update := streams.NewActivityStreamsUpdate()
+
+	ap.SetJSONLDId(update, updateID)
+	ap.AppendTargetIRIs(update, updateTarget)
+	ap.AppendActorIRIs(update, updateActor)
+	ap.SetPublished(update, updatePublished)
+
+	objectProp := streams.NewActivityStreamsObjectProperty()
+	objectProp.AppendActivityStreamsNote(updateNote)
+	update.SetActivityStreamsObject(objectProp)
+
+	return update
+}
+
 func newAPAnnounce(announceID *url.URL, announceActor *url.URL, announcePublished time.Time, announceTo *url.URL, announceNote vocab.ActivityStreamsNote) vocab.ActivityStreamsAnnounce {
 	announce := streams.NewActivityStreamsAnnounce()