[bugfix] Fix top-level posts with a mention being counted as replies when doing `exclude_replies` (#3689)

* [bugfix] Fix top-level posts with a mention being counted as replies

* add index for new reply exclusion query

2 files changed, 100 insertions, 7 deletions

diff --git a/internal/db/bundb/account.go b/internal/db/bundb/account.go
index 3d85df381..c5f9148a9 100644
--- a/internal/db/bundb/account.go
+++ b/internal/db/bundb/account.go
@@ -899,15 +899,19 @@ func (a *accountDB) GetAccountStatuses(ctx context.Context, accountID string, li
 
 	if excludeReplies {
 		q = q.WhereGroup(" AND ", func(q *bun.SelectQuery) *bun.SelectQuery {
+			// We're excluding replies so
+			// only include posts if they:
 			return q.
-				// Do include self replies (threads), but
-				// don't include replies to other people.
-				Where("? = ?", bun.Ident("status.in_reply_to_account_id"), accountID).
-				WhereOr("? IS NULL", bun.Ident("status.in_reply_to_uri"))
+				// Don't reply to anything OR
+				Where("? IS NULL", bun.Ident("status.in_reply_to_uri")).
+				// reply to self AND don't mention
+				// anyone (ie., self-reply threads).
+				WhereGroup(" OR ", func(q *bun.SelectQuery) *bun.SelectQuery {
+					q = q.Where("? = ?", bun.Ident("status.in_reply_to_account_id"), accountID)
+					q = whereArrayIsNullOrEmpty(q, bun.Ident("status.mentions"))
+					return q
+				})
 		})
-		// Don't include replies that mention other people:
-		// for example, an account's reply to its own reply to someone else.
-		q = whereArrayIsNullOrEmpty(q, bun.Ident("status.mentions"))
 	}
 
 	if excludeReblogs {
diff --git a/internal/db/bundb/migrations/20250126162825_top_level_mention_replies_fix.go b/internal/db/bundb/migrations/20250126162825_top_level_mention_replies_fix.go
new file mode 100644
index 000000000..0b198f17b
--- /dev/null
+++ b/internal/db/bundb/migrations/20250126162825_top_level_mention_replies_fix.go
@@ -0,0 +1,89 @@
+// 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 migrations
+
+import (
+	"context"
+
+	gtsmodel "github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
+	"github.com/superseriousbusiness/gotosocial/internal/log"
+	"github.com/uptrace/bun"
+	"github.com/uptrace/bun/dialect"
+)
+
+func init() {
+	up := func(ctx context.Context, db *bun.DB) error {
+		var expression string
+		switch db.Dialect().Name() {
+		case dialect.PG:
+			expression = "(mentions IS NULL OR CARDINALITY(mentions) = 0)"
+		case dialect.SQLite:
+			expression = "(mentions IS NULL OR json_array_length(mentions) = 0)"
+		default:
+			panic("db conn was neither pg not sqlite")
+		}
+
+		return db.RunInTx(ctx, nil, func(ctx context.Context, tx bun.Tx) error {
+			log.Info(ctx,
+				"removing previous statuses_account_view_idx and reindexing statuses; "+
+					"this may take a few minutes, please don't interrupt this migration",
+			)
+
+			// Remove old index with columns
+			// in really awkward order.
+			if _, err := tx.
+				NewDropIndex().
+				Model((*gtsmodel.Status)(nil)).
+				Index("statuses_account_view_idx").
+				IfExists().
+				Exec(ctx); err != nil {
+				return err
+			}
+
+			// Create new index with
+			// columns in desired order.
+			if _, err := tx.
+				NewCreateIndex().
+				Model((*gtsmodel.Status)(nil)).
+				Index("statuses_account_view_idx").
+				Column(
+					"account_id",
+					"in_reply_to_uri",
+					"in_reply_to_account_id",
+				).
+				ColumnExpr(expression).
+				ColumnExpr("id DESC").
+				IfNotExists().
+				Exec(ctx); err != nil {
+				return err
+			}
+
+			return nil
+		})
+	}
+
+	down := func(ctx context.Context, db *bun.DB) error {
+		return db.RunInTx(ctx, nil, func(ctx context.Context, tx bun.Tx) error {
+			return nil
+		})
+	}
+
+	if err := Migrations.Register(up, down); err != nil {
+		panic(err)
+	}
+}