@@ -63,7 +63,7 @@ require (

 	github.com/miekg/dns v1.1.57

 	github.com/mistifyio/go-zfs/v3 v3.0.1

 	github.com/mitchellh/copystructure v1.2.0

-	github.com/moby/buildkit v0.18.1

+	github.com/moby/buildkit v0.18.2

 	github.com/moby/docker-image-spec v1.3.1

 	github.com/moby/ipvs v1.1.0

 	github.com/moby/locker v1.0.1

@@ -364,8 +364,8 @@ github.com/mitchellh/mapstructure v0.0.0-20160808181253-ca63d7c062ee/go.mod h1:F

 github.com/mitchellh/reflectwalk v1.0.2 h1:G2LzWKi524PWgd3mLHV8Y5k7s6XUvT0Gef6zxSIeXaQ=

 github.com/mitchellh/reflectwalk v1.0.2/go.mod h1:mSTlrgnPZtwu0c4WaC2kGObEpuNDbx0jmZXqmk4esnw=

 github.com/mndrix/tap-go v0.0.0-20171203230836-629fa407e90b/go.mod h1:pzzDgJWZ34fGzaAZGFW22KVZDfyrYW+QABMrWnJBnSs=

-github.com/moby/buildkit v0.18.1 h1:Iwrz2F/Za2Gjkpwu3aM2LX92AFfJCJe2oNnvGNvh2Rc=

-github.com/moby/buildkit v0.18.1/go.mod h1:vCR5CX8NGsPTthTg681+9kdmfvkvqJBXEv71GZe5msU=

+github.com/moby/buildkit v0.18.2 h1:l86uBvxh4ntNoUUg3Y0eGTbKg1PbUh6tawJ4Xt75SpQ=

+github.com/moby/buildkit v0.18.2/go.mod h1:vCR5CX8NGsPTthTg681+9kdmfvkvqJBXEv71GZe5msU=

 github.com/moby/docker-image-spec v1.3.1 h1:jMKff3w6PgbfSa69GfNg+zN/XLhfXJGnEx3Nl2EsFP0=

 github.com/moby/docker-image-spec v1.3.1/go.mod h1:eKmb5VW8vQEh/BAr2yvVNvuiJuY6UIocYsFu/DxxRpo=

 github.com/moby/ipvs v1.1.0 h1:ONN4pGaZQgAx+1Scz5RvWV4Q7Gb+mvfRh3NsPS+1XQQ=

@@ -16,7 +16,6 @@ import (

 // For example, after marshalling a LLB state and sending over the wire, the

 // LLB state can be reconstructed from the definition.

 type DefinitionOp struct {

-	MarshalCache

 	mu         sync.Mutex

 	ops        map[digest.Digest]*pb.Op

 	defs       map[digest.Digest][]byte

@@ -8,7 +8,7 @@ import (

 )

 type DiffOp struct {

-	MarshalCache

+	cache       MarshalCache

 	lower       Output

 	upper       Output

 	output      Output

@@ -31,7 +31,10 @@ func (m *DiffOp) Validate(ctx context.Context, constraints *Constraints) error {

 }

 func (m *DiffOp) Marshal(ctx context.Context, constraints *Constraints) (digest.Digest, []byte, *pb.OpMetadata, []*SourceLocation, error) {

-	if dgst, dt, md, srcs, err := m.Load(constraints); err == nil {

+	cache := m.cache.Acquire()

+	defer cache.Release()

+

+	if dgst, dt, md, srcs, err := cache.Load(constraints); err == nil {

 		return dgst, dt, md, srcs, nil

 	}

 	if err := m.Validate(ctx, constraints); err != nil {

@@ -72,7 +75,7 @@ func (m *DiffOp) Marshal(ctx context.Context, constraints *Constraints) (digest.

 		return "", nil, nil, nil, err

 	}

-	return m.Store(dt, md, m.constraints.SourceLocations, constraints)

+	return cache.Store(dt, md, m.constraints.SourceLocations, constraints)

 }

 func (m *DiffOp) Output() Output {

@@ -51,7 +51,7 @@ type mount struct {

 }

 type ExecOp struct {

-	MarshalCache

+	cache       MarshalCache

 	proxyEnv    *ProxyEnv

 	root        Output

 	mounts      []*mount

@@ -63,6 +63,9 @@ type ExecOp struct {

 }

 func (e *ExecOp) AddMount(target string, source Output, opt ...MountOption) Output {

+	cache := e.cache.Acquire()

+	defer cache.Release()

+

 	m := &mount{

 		target: target,

 		source: source,

@@ -84,7 +87,7 @@ func (e *ExecOp) AddMount(target string, source Output, opt ...MountOption) Outp

 		}

 		m.output = o

 	}

-	e.Store(nil, nil, nil, nil)

+	cache.Store(nil, nil, nil, nil)

 	e.isValidated = false

 	return m.output

 }

@@ -128,7 +131,10 @@ func (e *ExecOp) Validate(ctx context.Context, c *Constraints) error {

 }

 func (e *ExecOp) Marshal(ctx context.Context, c *Constraints) (digest.Digest, []byte, *pb.OpMetadata, []*SourceLocation, error) {

-	if dgst, dt, md, srcs, err := e.Load(c); err == nil {

+	cache := e.cache.Acquire()

+	defer cache.Release()

+

+	if dgst, dt, md, srcs, err := cache.Load(c); err == nil {

 		return dgst, dt, md, srcs, nil

 	}

@@ -446,7 +452,7 @@ func (e *ExecOp) Marshal(ctx context.Context, c *Constraints) (digest.Digest, []

 	if err != nil {

 		return "", nil, nil, nil, err

 	}

-	return e.Store(dt, md, e.constraints.SourceLocations, c)

+	return cache.Store(dt, md, e.constraints.SourceLocations, c)

 }

 func (e *ExecOp) Output() Output {

@@ -746,7 +746,10 @@ func (ms *marshalState) add(fa *FileAction, c *Constraints) (*fileActionState, e

 }

 func (f *FileOp) Marshal(ctx context.Context, c *Constraints) (digest.Digest, []byte, *pb.OpMetadata, []*SourceLocation, error) {

-	if dgst, dt, md, srcs, err := f.Load(c); err == nil {

+	cache := f.Acquire()

+	defer cache.Release()

+

+	if dgst, dt, md, srcs, err := cache.Load(c); err == nil {

 		return dgst, dt, md, srcs, nil

 	}

@@ -816,7 +819,7 @@ func (f *FileOp) Marshal(ctx context.Context, c *Constraints) (digest.Digest, []

 	if err != nil {

 		return "", nil, nil, nil, err

 	}

-	return f.Store(dt, md, f.constraints.SourceLocations, c)

+	return cache.Store(dt, md, f.constraints.SourceLocations, c)

 }

 func normalizePath(parent, p string, keepSlash bool) string {

@@ -117,30 +117,45 @@ func MarshalConstraints(base, override *Constraints) (*pb.Op, *pb.OpMetadata) {

 }

 type MarshalCache struct {

-	cache sync.Map

+	mu    sync.Mutex

+	cache map[*Constraints]*marshalCacheResult

 }

-func (mc *MarshalCache) Load(c *Constraints) (digest.Digest, []byte, *pb.OpMetadata, []*SourceLocation, error) {

-	v, ok := mc.cache.Load(c)

+type MarshalCacheInstance struct {

+	*MarshalCache

+}

+

+func (mc *MarshalCache) Acquire() *MarshalCacheInstance {

+	mc.mu.Lock()

+	return &MarshalCacheInstance{mc}

+}

+

+func (mc *MarshalCacheInstance) Load(c *Constraints) (digest.Digest, []byte, *pb.OpMetadata, []*SourceLocation, error) {

+	res, ok := mc.cache[c]

 	if !ok {

 		return "", nil, nil, nil, cerrdefs.ErrNotFound

 	}

-

-	res := v.(*marshalCacheResult)

 	return res.digest, res.dt, res.md, res.srcs, nil

 }

-func (mc *MarshalCache) Store(dt []byte, md *pb.OpMetadata, srcs []*SourceLocation, c *Constraints) (digest.Digest, []byte, *pb.OpMetadata, []*SourceLocation, error) {

+func (mc *MarshalCacheInstance) Store(dt []byte, md *pb.OpMetadata, srcs []*SourceLocation, c *Constraints) (digest.Digest, []byte, *pb.OpMetadata, []*SourceLocation, error) {

 	res := &marshalCacheResult{

 		digest: digest.FromBytes(dt),

 		dt:     dt,

 		md:     md,

 		srcs:   srcs,

 	}

-	mc.cache.Store(c, res)

+	if mc.cache == nil {

+		mc.cache = make(map[*Constraints]*marshalCacheResult)

+	}

+	mc.cache[c] = res

 	return res.digest, res.dt, res.md, res.srcs, nil

 }

+func (mc *MarshalCacheInstance) Release() {

+	mc.mu.Unlock()

+}

+

 type marshalCacheResult struct {

 	digest digest.Digest

 	dt     []byte

@@ -9,7 +9,7 @@ import (

 )

 type MergeOp struct {

-	MarshalCache

+	cache       MarshalCache

 	inputs      []Output

 	output      Output

 	constraints Constraints

@@ -32,7 +32,10 @@ func (m *MergeOp) Validate(ctx context.Context, constraints *Constraints) error

 }

 func (m *MergeOp) Marshal(ctx context.Context, constraints *Constraints) (digest.Digest, []byte, *pb.OpMetadata, []*SourceLocation, error) {

-	if dgst, dt, md, srcs, err := m.Load(constraints); err == nil {

+	cache := m.cache.Acquire()

+	defer cache.Release()

+

+	if dgst, dt, md, srcs, err := cache.Load(constraints); err == nil {

 		return dgst, dt, md, srcs, nil

 	}

@@ -59,7 +62,7 @@ func (m *MergeOp) Marshal(ctx context.Context, constraints *Constraints) (digest

 		return "", nil, nil, nil, err

 	}

-	return m.Store(dt, md, m.constraints.SourceLocations, constraints)

+	return cache.Store(dt, md, m.constraints.SourceLocations, constraints)

 }

 func (m *MergeOp) Output() Output {

@@ -20,7 +20,7 @@ import (

 )

 type SourceOp struct {

-	MarshalCache

+	cache       MarshalCache

 	id          string

 	attrs       map[string]string

 	output      Output

@@ -49,7 +49,10 @@ func (s *SourceOp) Validate(ctx context.Context, c *Constraints) error {

 }

 func (s *SourceOp) Marshal(ctx context.Context, constraints *Constraints) (digest.Digest, []byte, *pb.OpMetadata, []*SourceLocation, error) {

-	if dgst, dt, md, srcs, err := s.Load(constraints); err == nil {

+	cache := s.cache.Acquire()

+	defer cache.Release()

+

+	if dgst, dt, md, srcs, err := cache.Load(constraints); err == nil {

 		return dgst, dt, md, srcs, nil

 	}

@@ -82,7 +85,7 @@ func (s *SourceOp) Marshal(ctx context.Context, constraints *Constraints) (diges

 		return "", nil, nil, nil, err

 	}

-	return s.Store(dt, md, s.constraints.SourceLocations, constraints)

+	return cache.Store(dt, md, s.constraints.SourceLocations, constraints)

 }

 func (s *SourceOp) Output() Output {

@@ -376,6 +376,7 @@ func toDispatchState(ctx context.Context, dt []byte, opt ConvertOpt) (*dispatchS

 					}

 				}

 				allDispatchStates.addState(ds)

+				ds.base = nil // reset base set by addState

 				continue

 			}

 		}

@@ -1065,6 +1066,8 @@ func (ds *dispatchState) init() {

 	ds.state = ds.base.state

 	ds.platform = ds.base.platform

 	ds.image = clone(ds.base.image)

+	// onbuild triggers to not carry over from base stage

+	ds.image.Config.OnBuild = nil

 	ds.baseImg = cloneX(ds.base.baseImg)

 	// Utilize the same path index as our base image so we propagate

 	// the paths we use back to the base image.

@@ -12,6 +12,7 @@ func clone(src dockerspec.DockerOCIImage) dockerspec.DockerOCIImage {

 	img.Config.Env = append([]string{}, src.Config.Env...)

 	img.Config.Cmd = append([]string{}, src.Config.Cmd...)

 	img.Config.Entrypoint = append([]string{}, src.Config.Entrypoint...)

+	img.Config.OnBuild = append([]string{}, src.Config.OnBuild...)

 	return img

 }

@@ -699,7 +699,7 @@ github.com/mitchellh/hashstructure/v2

 # github.com/mitchellh/reflectwalk v1.0.2

 ## explicit

 github.com/mitchellh/reflectwalk

-# github.com/moby/buildkit v0.18.1

+# github.com/moby/buildkit v0.18.2

 ## explicit; go 1.22.0

 github.com/moby/buildkit/api/services/control

 github.com/moby/buildkit/api/types