cache: remove MigrateV2

This migration code was added in BuildKit v0.7.0 (Docker v20.10.0)
in 31a9aee. That was in 2019, which
is now 6 Years ago, so it's very unlikely for the old files to be still
present.

Removing this code would impact users migrating from Docker 19.03 or
older, which are versions that reached EOL many years ago, so very
unlikely.

Signed-off-by: Sebastiaan van Stijn <[email protected]>

Author: thaJeztah

cache/migrate_v2.go

@@ -12,7 +12,6 @@ import (
 	"github.com/containerd/containerd/v2/core/leases"
 	"github.com/containerd/containerd/v2/pkg/gc"
 	"github.com/containerd/platforms"
-	"github.com/moby/buildkit/cache"
 	"github.com/moby/buildkit/cache/metadata"
 	"github.com/moby/buildkit/executor/containerdexecutor"
 	"github.com/moby/buildkit/executor/oci"
@@ -135,19 +134,6 @@ func newContainerd(client *ctd.Client, workerOpts WorkerOptions) (base.WorkerOpt
 		}
 	}
 
-	snap := containerdsnapshot.NewSnapshotter(workerOpts.SnapshotterName, client.SnapshotService(workerOpts.SnapshotterName), workerOpts.Namespace, nil)
-
-	if err := cache.MigrateV2(
-		context.TODO(),
-		filepath.Join(root, "metadata.db"),
-		filepath.Join(root, "metadata_v2.db"),
-		cs,
-		snap,
-		lm,
-	); err != nil {
-		return base.WorkerOpt{}, err
-	}
-
 	md, err := metadata.NewStore(filepath.Join(root, "metadata_v2.db"))
 	if err != nil {
 		return base.WorkerOpt{}, err
@@ -174,7 +160,7 @@ func newContainerd(client *ctd.Client, workerOpts WorkerOptions) (base.WorkerOpt
 		MetadataStore:    md,
 		NetworkProviders: np,
 		Executor:         containerdexecutor.New(executorOpts),
-		Snapshotter:      snap,
+		Snapshotter:      containerdsnapshot.NewSnapshotter(workerOpts.SnapshotterName, client.SnapshotService(workerOpts.SnapshotterName), workerOpts.Namespace, nil),
 		ContentStore:     cs,
 		Applier:          winlayers.NewFileSystemApplierWithWindows(cs, df),
 		Differ:           winlayers.NewWalkingDiffWithWindows(cs, df),

worker/containerd/containerd.go

@@ -15,7 +15,6 @@ import (
 	"github.com/containerd/containerd/v2/plugins/content/local"
 	"github.com/containerd/containerd/v2/plugins/diff/walking"
 	"github.com/containerd/platforms"
-	"github.com/moby/buildkit/cache"
 	"github.com/moby/buildkit/cache/metadata"
 	"github.com/moby/buildkit/executor/oci"
 	"github.com/moby/buildkit/executor/resources"
@@ -130,18 +129,6 @@ func NewWorkerOpt(root string, snFactory SnapshotterFactory, rootless bool, proc
 	}
 
 	maps.Copy(xlabels, labels)
-	lm := leaseutil.WithNamespace(ctdmetadata.NewLeaseManager(mdb), "buildkit")
-	snap := containerdsnapshot.NewSnapshotter(snFactory.Name, mdb.Snapshotter(snFactory.Name), "buildkit", idmap)
-	if err := cache.MigrateV2(
-		context.TODO(),
-		filepath.Join(root, "metadata.db"),
-		filepath.Join(root, "metadata_v2.db"),
-		c,
-		snap,
-		lm,
-	); err != nil {
-		return opt, err
-	}
 
 	md, err := metadata.NewStore(filepath.Join(root, "metadata_v2.db"))
 	if err != nil {
@@ -155,14 +142,14 @@ func NewWorkerOpt(root string, snFactory SnapshotterFactory, rootless bool, proc
 		MetadataStore:    md,
 		NetworkProviders: np,
 		Executor:         exe,
-		Snapshotter:      snap,
+		Snapshotter:      containerdsnapshot.NewSnapshotter(snFactory.Name, mdb.Snapshotter(snFactory.Name), "buildkit", idmap),
 		ContentStore:     c,
 		Applier:          winlayers.NewFileSystemApplierWithWindows(c, apply.NewFileSystemApplier(c)),
 		Differ:           winlayers.NewWalkingDiffWithWindows(c, walking.NewWalkingDiff(c)),
 		ImageStore:       nil, // explicitly
 		Platforms:        []ocispecs.Platform{platforms.Normalize(platforms.DefaultSpec())},
 		IdentityMapping:  idmap,
-		LeaseManager:     lm,
+		LeaseManager:     leaseutil.WithNamespace(ctdmetadata.NewLeaseManager(mdb), "buildkit"),
 		GarbageCollect:   mdb.GarbageCollect,
 		ParallelismSem:   parallelismSem,
 		MountPoolRoot:    filepath.Join(root, "cachemounts"),