build: move solveOpt to local struct type

*client.SolveOpt in driver code is only used by build code.
For a clear separation of concerns, move it to an internal
struct type only accessible by BuildWithResultHandler func.

Signed-off-by: CrazyMax <1951866+crazy-max@users.noreply.github.com>

build/build.go

@@ -118,6 +118,11 @@ type NamedContext struct {
 	State *llb.State
 }
 
+type reqForNode struct {
+	*resolvedNode
+	so *client.SolveOpt
+}
+
 func filterAvailableNodes(nodes []builder.Node) ([]builder.Node, error) {
 	out := make([]builder.Node, 0, len(nodes))
 	err := errors.Errorf("no drivers found")
@@ -519,6 +524,7 @@ func BuildWithResultHandler(ctx context.Context, nodes []builder.Node, opt map[s
 		}
 	}()
 
+	reqForNodes := make(map[string][]*reqForNode)
 	eg, ctx := errgroup.WithContext(ctx)
 
 	for k, opt := range opt {
@@ -528,6 +534,7 @@ func BuildWithResultHandler(ctx context.Context, nodes []builder.Node, opt map[s
 		if err != nil {
 			logrus.WithError(err).Warn("current commit information was not captured by the build")
 		}
+		var reqn []*reqForNode
 		for _, np := range drivers[k] {
 			if np.Node().Driver.IsMobyDriver() {
 				hasMobyDriver = true
@@ -548,8 +555,12 @@ func BuildWithResultHandler(ctx context.Context, nodes []builder.Node, opt map[s
 				so.FrontendAttrs[k] = v
 			}
 			defers = append(defers, release)
-			np.SolveOpt = so
+			reqn = append(reqn, &reqForNode{
+				resolvedNode: np,
+				so:           so,
+			})
 		}
+		reqForNodes[k] = reqn
 		for _, at := range opt.Session {
 			if s, ok := at.(interface {
 				SetLogger(progresswriter.Logger)
@@ -562,8 +573,8 @@ func BuildWithResultHandler(ctx context.Context, nodes []builder.Node, opt map[s
 
 		// validate for multi-node push
 		if hasMobyDriver && multiDriver {
-			for _, np := range drivers[k] {
+			for _, np := range reqForNodes[k] {
-				for _, e := range np.SolveOpt.Exports {
+				for _, e := range np.so.Exports {
 					if e.Type == "moby" {
 						if ok, _ := strconv.ParseBool(e.Attrs["push"]); ok {
 							return nil, errors.Errorf("multi-node push can't currently be performed with the docker driver, please switch to a different driver")
@@ -576,9 +587,9 @@ func BuildWithResultHandler(ctx context.Context, nodes []builder.Node, opt map[s
 
 	// validate that all links between targets use same drivers
 	for name := range opt {
-		dps := drivers[name]
+		dps := reqForNodes[name]
 		for i, dp := range dps {
-			so := drivers[name][i].SolveOpt
+			so := reqForNodes[name][i].so
 			for k, v := range so.FrontendAttrs {
 				if strings.HasPrefix(k, "context:") && strings.HasPrefix(v, "target:") {
 					k2 := strings.TrimPrefix(v, "target:")
@@ -606,7 +617,7 @@ func BuildWithResultHandler(ctx context.Context, nodes []builder.Node, opt map[s
 	results := waitmap.New()
 
 	multiTarget := len(opt) > 1
-	childTargets := calculateChildTargets(drivers, opt)
+	childTargets := calculateChildTargets(reqForNodes, opt)
 
 	for k, opt := range opt {
 		err := func(k string) error {
@@ -630,7 +641,7 @@ func BuildWithResultHandler(ctx context.Context, nodes []builder.Node, opt map[s
 			for i, dp := range dps {
 				i, dp := i, dp
 				node := dp.Node()
-				so := drivers[k][i].SolveOpt
+				so := reqForNodes[k][i].so
 				if multiDriver {
 					for i, e := range so.Exports {
 						switch e.Type {
@@ -1299,12 +1310,12 @@ func resultKey(index int, name string) string {
 }
 
 // calculateChildTargets returns all the targets that depend on current target for reverse index
-func calculateChildTargets(drivers map[string][]*resolvedNode, opt map[string]Options) map[string][]string {
+func calculateChildTargets(reqs map[string][]*reqForNode, opt map[string]Options) map[string][]string {
 	out := make(map[string][]string)
 	for name := range opt {
-		dps := drivers[name]
+		dps := reqs[name]
 		for i, dp := range dps {
-			so := drivers[name][i].SolveOpt
+			so := reqs[name][i].so
 			for k, v := range so.FrontendAttrs {
 				if strings.HasPrefix(k, "context:") && strings.HasPrefix(v, "target:") {
 					target := resultKey(dp.driverIndex, strings.TrimPrefix(v, "target:"))

build/driver.go

@@ -19,8 +19,6 @@ import (
 )
 
 type resolvedNode struct {
-	SolveOpt *client.SolveOpt
-
 	resolver    *nodeResolver
 	driverIndex int
 	platforms   []specs.Platform