[bugfix] Fix paging for empty items (#2236)

* use minID properly for public timeline

* return paged response properly even when 0 items

* use gtserror

* page more consistently (for now)

* test

* aaa

4 files changed, 36 insertions, 49 deletions

diff --git a/internal/processing/account/bookmarks.go b/internal/processing/account/bookmarks.go
index 88a02786e..9cbc3db26 100644
--- a/internal/processing/account/bookmarks.go
+++ b/internal/processing/account/bookmarks.go
@@ -25,7 +25,6 @@ import (
 	"github.com/superseriousbusiness/gotosocial/internal/db"
 	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
 	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
-	"github.com/superseriousbusiness/gotosocial/internal/id"
 	"github.com/superseriousbusiness/gotosocial/internal/log"
 	"github.com/superseriousbusiness/gotosocial/internal/util"
 )
@@ -34,15 +33,23 @@ import (
 // Paging for this response is done based on bookmark ID rather than status ID.
 func (p *Processor) BookmarksGet(ctx context.Context, requestingAccount *gtsmodel.Account, limit int, maxID string, minID string) (*apimodel.PageableResponse, gtserror.WithCode) {
 	bookmarks, err := p.state.DB.GetStatusBookmarks(ctx, requestingAccount.ID, limit, maxID, minID)
-	if err != nil {
+	if err != nil && !errors.Is(err, db.ErrNoEntries) {
 		return nil, gtserror.NewErrorInternalError(err)
 	}
 
+	count := len(bookmarks)
+	if count == 0 {
+		return util.EmptyPageableResponse(), nil
+	}
+
 	var (
-		count          = len(bookmarks)
-		items          = make([]interface{}, 0, count)
-		nextMaxIDValue = id.Highest
-		prevMinIDValue = id.Lowest
+		items = make([]interface{}, 0, count)
+
+		// Set next + prev values before filtering and API
+		// converting, so caller can still page properly.
+		// Page based on bookmark ID, not status ID.
+		nextMaxIDValue = bookmarks[count-1].ID
+		prevMinIDValue = bookmarks[0].ID
 	)
 
 	for _, bookmark := range bookmarks {
@@ -73,23 +80,6 @@ func (p *Processor) BookmarksGet(ctx context.Context, requestingAccount *gtsmode
 			continue
 		}
 		items = append(items, item)
-
-		// Page based on bookmark ID, not status ID.
-		// Note that we only set these values here
-		// when we're certain that the caller is able
-		// to see the status, *and* we're sure that
-		// we can produce an api model representation.
-		if bookmark.ID < nextMaxIDValue {
-			nextMaxIDValue = bookmark.ID // Lowest ID (for paging down).
-		}
-
-		if bookmark.ID > prevMinIDValue {
-			prevMinIDValue = bookmark.ID // Highest ID (for paging up).
-		}
-	}
-
-	if len(items) == 0 {
-		return util.EmptyPageableResponse(), nil
 	}
 
 	return util.PackagePageableResponse(util.PageableResponseParams{
diff --git a/internal/processing/account/statuses.go b/internal/processing/account/statuses.go
index 99e9edbcf..716157a14 100644
--- a/internal/processing/account/statuses.go
+++ b/internal/processing/account/statuses.go
@@ -74,21 +74,8 @@ func (p *Processor) StatusesGet(
 		return nil, gtserror.NewErrorInternalError(err)
 	}
 
-	if len(statuses) == 0 {
-		return util.EmptyPageableResponse(), nil
-	}
-
-	// Filtering + serialization process is the same for
-	// both pinned status queries and 'normal' ones.
-	filtered, err := p.filter.StatusesVisible(ctx, requestingAccount, statuses)
-	if err != nil {
-		return nil, gtserror.NewErrorInternalError(err)
-	}
-
-	count := len(filtered)
+	count := len(statuses)
 	if count == 0 {
-		// After filtering there were
-		// no statuses left to serve.
 		return util.EmptyPageableResponse(), nil
 	}
 
@@ -97,10 +84,17 @@ func (p *Processor) StatusesGet(
 
 		// Set next + prev values before filtering and API
 		// converting, so caller can still page properly.
-		nextMaxIDValue = filtered[count-1].ID
-		prevMinIDValue = filtered[0].ID
+		nextMaxIDValue = statuses[count-1].ID
+		prevMinIDValue = statuses[0].ID
 	)
 
+	// Filtering + serialization process is the same for
+	// both pinned status queries and 'normal' ones.
+	filtered, err := p.filter.StatusesVisible(ctx, requestingAccount, statuses)
+	if err != nil {
+		return nil, gtserror.NewErrorInternalError(err)
+	}
+
 	for _, s := range filtered {
 		// Convert filtered statuses to API statuses.
 		item, err := p.converter.StatusToAPIStatus(ctx, s, requestingAccount)
diff --git a/internal/processing/admin/report.go b/internal/processing/admin/report.go
index 0f47cf839..32f05719b 100644
--- a/internal/processing/admin/report.go
+++ b/internal/processing/admin/report.go
@@ -19,6 +19,7 @@ package admin
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"strconv"
 	"time"
@@ -45,17 +46,20 @@ func (p *Processor) ReportsGet(
 	limit int,
 ) (*apimodel.PageableResponse, gtserror.WithCode) {
 	reports, err := p.state.DB.GetReports(ctx, resolved, accountID, targetAccountID, maxID, sinceID, minID, limit)
-	if err != nil {
-		if err == db.ErrNoEntries {
-			return util.EmptyPageableResponse(), nil
-		}
+	if err != nil && !errors.Is(err, db.ErrNoEntries) {
 		return nil, gtserror.NewErrorInternalError(err)
 	}
 
 	count := len(reports)
-	items := make([]interface{}, 0, count)
-	nextMaxIDValue := reports[count-1].ID
-	prevMinIDValue := reports[0].ID
+	if count == 0 {
+		return util.EmptyPageableResponse(), nil
+	}
+
+	var (
+		items          = make([]interface{}, 0, count)
+		nextMaxIDValue = reports[count-1].ID
+		prevMinIDValue = reports[0].ID
+	)
 
 	for _, r := range reports {
 		item, err := p.converter.ReportToAdminAPIReport(ctx, r, account)
@@ -65,7 +69,7 @@ func (p *Processor) ReportsGet(
 		items = append(items, item)
 	}
 
-	extraQueryParams := []string{}
+	extraQueryParams := make([]string, 0, 3)
 	if resolved != nil {
 		extraQueryParams = append(extraQueryParams, "resolved="+strconv.FormatBool(*resolved))
 	}
diff --git a/internal/processing/timeline/public.go b/internal/processing/timeline/public.go
index eb8c0c381..0ace00c0b 100644
--- a/internal/processing/timeline/public.go
+++ b/internal/processing/timeline/public.go
@@ -20,7 +20,6 @@ package timeline
 import (
 	"context"
 	"errors"
-	"fmt"
 
 	apimodel "github.com/superseriousbusiness/gotosocial/internal/api/model"
 	"github.com/superseriousbusiness/gotosocial/internal/db"
@@ -33,7 +32,7 @@ import (
 func (p *Processor) PublicTimelineGet(ctx context.Context, authed *oauth.Auth, maxID string, sinceID string, minID string, limit int, local bool) (*apimodel.PageableResponse, gtserror.WithCode) {
 	statuses, err := p.state.DB.GetPublicTimeline(ctx, maxID, sinceID, minID, limit, local)
 	if err != nil && !errors.Is(err, db.ErrNoEntries) {
-		err = fmt.Errorf("PublicTimelineGet: db error getting statuses: %w", err)
+		err = gtserror.Newf("db error getting statuses: %w", err)
 		return nil, gtserror.NewErrorInternalError(err)
 	}