Refactor LFS GC functions

- Remove options that currently aren't set
on `GarbageCollectLFSMetaObjectsOptions` and
`IterateLFSMetaObjectsForRepoOptions`.
- Simplify `IterateRepositoryIDsWithLFSMetaObjects` and
`IterateLFSMetaObjectsForRepo`.
- `IterateLFSMetaObjectsForRepo` was previously able to get in a
loop (`gc-lfs` doctor check was able to reproduce this) because the code
expected that the records would be updated to not match the SQL query,
but that wasn't the case. Simply enforce that only records higher than
the latest `id` from the previous iteration are allowed.
- For `gc-lfs` doctor check this was because `UpdatedLessRecentlyThan`
option was not set, which caused that records just marked as active in
the iteration weren't being filtered.
- Add unit tests
- Most likely a regression from 2cc3a6381c.
- The bug with `gc-lfs` was found on Codeberg.

(cherry picked from commit 7ffa7f5bce)

models/git/lfs.go

@@ -337,58 +337,47 @@ func GetRepoLFSSize(ctx context.Context, repoID int64) (int64, error) {
 func IterateRepositoryIDsWithLFSMetaObjects(ctx context.Context, f func(ctx context.Context, repoID, count int64) error) error {
 	batchSize := setting.Database.IterateBufferSize
 	sess := db.GetEngine(ctx)
-	id := int64(0)
+	var start int
 	type RepositoryCount struct {
 		RepositoryID int64
 		Count        int64
 	}
 	for {
 		counts := make([]*RepositoryCount, 0, batchSize)
-		sess.Select("repository_id, COUNT(id) AS count").
+		if err := sess.Select("repository_id, COUNT(id) AS count").
 			Table("lfs_meta_object").
-			Where("repository_id > ?", id).
 			GroupBy("repository_id").
-			OrderBy("repository_id ASC")
-
-		if err := sess.Limit(batchSize, 0).Find(&counts); err != nil {
+			OrderBy("repository_id ASC").Limit(batchSize, start).Find(&counts); err != nil {
 			return err
 		}
 		if len(counts) == 0 {
 			return nil
 		}
+		start += len(counts)
 
 		for _, count := range counts {
 			if err := f(ctx, count.RepositoryID, count.Count); err != nil {
 				return err
 			}
 		}
-		id = counts[len(counts)-1].RepositoryID
 	}
 }
 
 // IterateLFSMetaObjectsForRepoOptions provides options for IterateLFSMetaObjectsForRepo
 type IterateLFSMetaObjectsForRepoOptions struct {
-	OlderThan                 timeutil.TimeStamp
-	UpdatedLessRecentlyThan   timeutil.TimeStamp
-	OrderByUpdated            bool
-	LoopFunctionAlwaysUpdates bool
+	OlderThan               timeutil.TimeStamp
+	UpdatedLessRecentlyThan timeutil.TimeStamp
 }
 
 // IterateLFSMetaObjectsForRepo provides a iterator for LFSMetaObjects per Repo
-func IterateLFSMetaObjectsForRepo(ctx context.Context, repoID int64, f func(context.Context, *LFSMetaObject, int64) error, opts *IterateLFSMetaObjectsForRepoOptions) error {
-	var start int
+func IterateLFSMetaObjectsForRepo(ctx context.Context, repoID int64, f func(context.Context, *LFSMetaObject) error, opts *IterateLFSMetaObjectsForRepoOptions) error {
 	batchSize := setting.Database.IterateBufferSize
 	engine := db.GetEngine(ctx)
-	type CountLFSMetaObject struct {
-		Count         int64
-		LFSMetaObject `xorm:"extends"`
-	}
-
 	id := int64(0)
 
 	for {
-		beans := make([]*CountLFSMetaObject, 0, batchSize)
-		sess := engine.Table("lfs_meta_object").Select("`lfs_meta_object`.*, COUNT(`l1`.oid) AS `count`").
+		beans := make([]*LFSMetaObject, 0, batchSize)
+		sess := engine.Table("lfs_meta_object").Select("`lfs_meta_object`.*").
 			Join("INNER", "`lfs_meta_object` AS l1", "`lfs_meta_object`.oid = `l1`.oid").
 			Where("`lfs_meta_object`.repository_id = ?", repoID)
 		if !opts.OlderThan.IsZero() {
@@ -397,25 +386,19 @@ func IterateLFSMetaObjectsForRepo(ctx context.Context, repoID int64, f func(cont
 		if !opts.UpdatedLessRecentlyThan.IsZero() {
 			sess.And("`lfs_meta_object`.updated_unix < ?", opts.UpdatedLessRecentlyThan)
 		}
-		sess.GroupBy("`lfs_meta_object`.id")
-		if opts.OrderByUpdated {
-			sess.OrderBy("`lfs_meta_object`.updated_unix ASC")
-		} else {
-			sess.And("`lfs_meta_object`.id > ?", id)
-			sess.OrderBy("`lfs_meta_object`.id ASC")
-		}
-		if err := sess.Limit(batchSize, start).Find(&beans); err != nil {
+		sess.GroupBy("`lfs_meta_object`.id").
+			And("`lfs_meta_object`.id > ?", id).
+			OrderBy("`lfs_meta_object`.id ASC")
+
+		if err := sess.Limit(batchSize, 0).Find(&beans); err != nil {
 			return err
 		}
 		if len(beans) == 0 {
 			return nil
 		}
-		if !opts.LoopFunctionAlwaysUpdates {
-			start += len(beans)
-		}
 
 		for _, bean := range beans {
-			if err := f(ctx, &bean.LFSMetaObject, bean.Count); err != nil {
+			if err := f(ctx, bean); err != nil {
 				return err
 			}
 		}