[bugfix] in fedi API CreateStatus(), handle case of data-race and ret…

…urn early (#2403)

internal/processing/workers/fromfediapi.go

@@ -151,21 +151,62 @@ func (p *Processor) ProcessFromFediAPI(ctx context.Context, fMsg messages.FromFe
 
 func (p *fediAPI) CreateStatus(ctx context.Context, fMsg messages.FromFediAPI) error {
 	var (
-		status *gtsmodel.Status
-		err    error
+		status     *gtsmodel.Status
+		statusable ap.Statusable
+		err        error
 	)
 
-	if fMsg.APObjectModel == nil /* i.e. forwarded */ {
+	var ok bool
+
+	switch {
+	case fMsg.APObjectModel != nil:
+		// A model was provided, extract this from message.
+		statusable, ok = fMsg.APObjectModel.(ap.Statusable)
+		if !ok {
+			return gtserror.Newf("cannot cast %T -> ap.Statusable", fMsg.APObjectModel)
+		}
+
+		// Create bare-bones model to pass
+		// into RefreshStatus(), which it will
+		// further populate and insert as new.
+		bareStatus := new(gtsmodel.Status)
+		bareStatus.Local = util.Ptr(false)
+		bareStatus.URI = ap.GetJSONLDId(statusable).String()
+
+		// Call RefreshStatus() to parse and process the provided
+		// statusable model, which it will use to further flesh out
+		// the bare bones model and insert it into the database.
+		status, statusable, err = p.federate.RefreshStatus(ctx,
+			fMsg.ReceivingAccount.Username,
+			bareStatus,
+			statusable,
+			true,
+		)
+		if err != nil {
+			return gtserror.Newf("error processing new status %s: %w", bareStatus.URI, err)
+		}
+
+	case fMsg.APIri != nil:
 		// Model was not set, deref with IRI (this is a forward).
 		// This will also cause the status to be inserted into the db.
-		status, err = p.statusFromAPIRI(ctx, fMsg)
-	} else {
-		// Model is set, ensure we have the most up-to-date model.
-		status, err = p.statusFromAPModel(ctx, fMsg)
+		status, statusable, err = p.federate.GetStatusByURI(ctx,
+			fMsg.ReceivingAccount.Username,
+			fMsg.APIri,
+		)
+		if err != nil {
+			return gtserror.Newf("error dereferencing forwarded status %s: %w", fMsg.APIri, err)
+		}
+
+	default:
+		return gtserror.New("neither APObjectModel nor APIri set")
 	}
 
-	if err != nil {
-		return gtserror.Newf("error extracting status from federatorMsg: %w", err)
+	if statusable == nil {
+		// Another thread beat us to
+		// creating this status! Return
+		// here and let the other thread
+		// handle timelining + notifying.
+		return nil
 	}
 
 	if status.InReplyToID != "" {
@@ -227,66 +268,6 @@ func (p *fediAPI) CreatePollVote(ctx context.Context, fMsg messages.FromFediAPI)
 	return nil
 }
 
-func (p *fediAPI) statusFromAPModel(ctx context.Context, fMsg messages.FromFediAPI) (*gtsmodel.Status, error) {
-	// AP statusable representation MUST have been set.
-	statusable, ok := fMsg.APObjectModel.(ap.Statusable)
-	if !ok {
-		return nil, gtserror.Newf("cannot cast %T -> ap.Statusable", fMsg.APObjectModel)
-	}
-
-	// Status may have been set (no problem if not).
-	status, _ := fMsg.GTSModel.(*gtsmodel.Status)
-
-	if status == nil {
-		// No status was set, create a bare-bones
-		// model for the deferencer to flesh-out,
-		// this indicates it is a new (to us) status.
-		status = &gtsmodel.Status{
-
-			// if coming in here status will ALWAYS be remote.
-			Local: util.Ptr(false),
-			URI:   ap.GetJSONLDId(statusable).String(),
-		}
-	}
-
-	// Call refresh on status to either update existing
-	// model, or parse + insert status from statusable data.
-	status, _, err := p.federate.RefreshStatus(
-		ctx,
-		fMsg.ReceivingAccount.Username,
-		status,
-		statusable,
-		false, // Don't force refresh.
-	)
-	if err != nil {
-		return nil, gtserror.Newf("error refreshing status: %w", err)
-	}
-
-	return status, nil
-}
-
-func (p *fediAPI) statusFromAPIRI(ctx context.Context, fMsg messages.FromFediAPI) (*gtsmodel.Status, error) {
-	// There should be a status IRI pinned to
-	// the federatorMsg for us to dereference.
-	if fMsg.APIri == nil {
-		const text = "neither APObjectModel nor APIri set"
-		return nil, gtserror.New(text)
-	}
-
-	// Get the status + ensure we have
-	// the most up-to-date version.
-	status, _, err := p.federate.GetStatusByURI(
-		ctx,
-		fMsg.ReceivingAccount.Username,
-		fMsg.APIri,
-	)
-	if err != nil {
-		return nil, gtserror.Newf("error getting status by uri %s: %w", fMsg.APIri, err)
-	}
-
-	return status, nil
-}
-
 func (p *fediAPI) CreateFollowReq(ctx context.Context, fMsg messages.FromFediAPI) error {
 	followRequest, ok := fMsg.GTSModel.(*gtsmodel.FollowRequest)
 	if !ok {
@@ -359,8 +340,7 @@ func (p *fediAPI) CreateAnnounce(ctx context.Context, fMsg messages.FromFediAPI)
 	// Dereference status that this boosts, note
 	// that this will handle dereferencing the status
 	// ancestors / descendants where appropriate.
-	if err := p.federate.DereferenceAnnounce(
-		ctx,
+	if err := p.federate.DereferenceAnnounce(ctx,
 		status,
 		fMsg.ReceivingAccount.Username,
 	); err != nil {
@@ -388,7 +368,7 @@ func (p *fediAPI) CreateAnnounce(ctx context.Context, fMsg messages.FromFediAPI)
 		log.Errorf(ctx, "error notifying announce: %v", err)
 	}
 
-	// Interaction counts changed on the boosted status;
+	// Interaction counts changed on the original status;
 	// uncache the prepared version from all timelines.
 	p.surface.invalidateStatusFromTimelines(ctx, status.ID)