tools/trim: fix list element removal bug

This breaks comprehension removal, but that beats
having bugs that break semantics.

Trim has seen its best time since all the changes to
the evaluator and should probably be rewritten come
the new evaluator.

Change-Id: I13b0aa58d3f2c1e4eb0fc617811be7d6078e6265
Reviewed-on: https://cue-review.googlesource.com/c/cue/+/6641
Reviewed-by: Marcel van Lohuizen <mpvl@golang.org>

cue/types.go

@@ -1101,6 +1101,9 @@ func (v Value) Len() Value {
 
 // Elem returns the value of undefined element types of lists and structs.
 func (v Value) Elem() (Value, bool) {
+	if v.v == nil {
+		return Value{}, false
+	}
 	ctx := v.ctx()
 	switch x := v.v.Value.(type) {
 	case *structLit:

doc/tutorial/kubernetes/quick/services/frontend/bartender/kube.cue

@@ -1,5 +1,9 @@
 package kube
 
+service: bartender: spec: ports: [{
+	port:       7080
+	targetPort: 7080
+}]
 deployment: bartender: spec: template: spec: containers: [{
 	image: "gcr.io/myproj/bartender:v0.1.34"
 	args: [

doc/tutorial/kubernetes/quick/services/frontend/breaddispatcher/kube.cue

@@ -1,5 +1,9 @@
 package kube
 
+service: breaddispatcher: spec: ports: [{
+	port:       7080
+	targetPort: 7080
+}]
 deployment: breaddispatcher: spec: template: spec: containers: [{
 	image: "gcr.io/myproj/breaddispatcher:v0.3.24"
 	args: [

doc/tutorial/kubernetes/quick/services/frontend/host/kube.cue

@@ -1,5 +1,9 @@
 package kube
 
+service: host: spec: ports: [{
+	port:       7080
+	targetPort: 7080
+}]
 deployment: host: spec: {
 	replicas: 2
 	template: spec: containers: [{

doc/tutorial/kubernetes/quick/services/frontend/maitred/kube.cue

@@ -1,5 +1,9 @@
 package kube
 
+service: maitred: spec: ports: [{
+	port:       7080
+	targetPort: 7080
+}]
 deployment: maitred: spec: template: spec: containers: [{
 	image: "gcr.io/myproj/maitred:v0.0.4"
 	args: [

doc/tutorial/kubernetes/quick/services/frontend/valeter/kube.cue

@@ -1,7 +1,9 @@
 package kube
 
 service: valeter: spec: ports: [{
-	name: "http"
+	port:       8080
+	targetPort: 8080
+	name:       "http"
 }]
 deployment: valeter: spec: template: spec: containers: [{
 	image: "gcr.io/myproj/valeter:v0.0.4"

doc/tutorial/kubernetes/quick/services/frontend/waiter/kube.cue

@@ -1,5 +1,9 @@
 package kube
 
+service: waiter: spec: ports: [{
+	port:       7080
+	targetPort: 7080
+}]
 deployment: waiter: spec: {
 	replicas: 5
 	template: spec: containers: [{

doc/tutorial/kubernetes/quick/services/frontend/waterdispatcher/kube.cue

@@ -1,7 +1,9 @@
 package kube
 
 service: waterdispatcher: spec: ports: [{
-	name: "http"
+	port:       7080
+	targetPort: 7080
+	name:       "http"
 }]
 deployment: waterdispatcher: spec: template: spec: containers: [{
 	image: "gcr.io/myproj/waterdispatcher:v0.0.48"

doc/tutorial/kubernetes/quick/services/infra/download/kube.cue

@@ -1,5 +1,9 @@
 package kube
 
+service: download: spec: ports: [{
+	port:       7080
+	targetPort: 7080
+}]
 deployment: download: spec: template: spec: containers: [{
 	image: "gcr.io/myproj/download:v0.0.2"
 	ports: [{

doc/tutorial/kubernetes/quick/services/infra/etcd/kube.cue

@@ -3,8 +3,12 @@ package kube
 service: etcd: spec: {
 	clusterIP: "None"
 	ports: [{
+		port:       2379
+		targetPort: 2379
 	}, {
-		name: "peer"
+		port:       2380
+		targetPort: 2380
+		name:       "peer"
 	}]
 }
 statefulSet: etcd: spec: {

doc/tutorial/kubernetes/quick/services/infra/events/kube.cue

@@ -1,7 +1,9 @@
 package kube
 
 service: events: spec: ports: [{
-	name: "grpc"
+	port:       7788
+	targetPort: 7788
+	name:       "grpc"
 }]
 deployment: events: spec: {
 	replicas: 2

doc/tutorial/kubernetes/quick/services/infra/tasks/service.cue

@@ -4,7 +4,8 @@ service: tasks: spec: {
 	type:           "LoadBalancer"
 	loadBalancerIP: "1.2.3.4" // static ip
 	ports: [{
-		port: 443
-		name: "http"
+		port:       443
+		targetPort: 7443
+		name:       "http"
 	}]
 }

doc/tutorial/kubernetes/quick/services/infra/updater/kube.cue

@@ -1,5 +1,9 @@
 package kube
 
+service: updater: spec: ports: [{
+	port:       8080
+	targetPort: 8080
+}]
 deployment: updater: spec: template: spec: {
 	volumes: [{
 		name: "secret-updater"

doc/tutorial/kubernetes/quick/services/infra/watcher/service.cue

@@ -4,6 +4,8 @@ service: watcher: spec: {
 	type:           "LoadBalancer"
 	loadBalancerIP: "1.2.3.4." // static ip
 	ports: [{
-		name: "http"
+		port:       7788
+		targetPort: 7788
+		name:       "http"
 	}]
 }

doc/tutorial/kubernetes/quick/services/kitchen/caller/kube.cue

@@ -1,5 +1,9 @@
 package kube
 
+service: caller: spec: ports: [{
+	port:       8080
+	targetPort: 8080
+}]
 deployment: caller: spec: {
 	replicas: 3
 	template: spec: {

doc/tutorial/kubernetes/quick/services/kitchen/dishwasher/kube.cue

@@ -1,5 +1,9 @@
 package kube
 
+service: dishwasher: spec: ports: [{
+	port:       8080
+	targetPort: 8080
+}]
 deployment: dishwasher: spec: {
 	replicas: 5
 	template: spec: {

doc/tutorial/kubernetes/quick/services/kitchen/expiditer/kube.cue

@@ -1,5 +1,9 @@
 package kube
 
+service: expiditer: spec: ports: [{
+	port:       8080
+	targetPort: 8080
+}]
 deployment: expiditer: spec: template: spec: containers: [{
 	image: "gcr.io/myproj/expiditer:v0.5.34"
 	args: [

doc/tutorial/kubernetes/quick/services/kitchen/headchef/kube.cue

@@ -1,5 +1,9 @@
 package kube
 
+service: headchef: spec: ports: [{
+	port:       8080
+	targetPort: 8080
+}]
 deployment: headchef: spec: template: spec: containers: [{
 	image: "gcr.io/myproj/headchef:v0.2.16"
 	volumeMounts: [{

doc/tutorial/kubernetes/quick/services/kitchen/linecook/kube.cue

@@ -1,5 +1,9 @@
 package kube
 
+service: linecook: spec: ports: [{
+	port:       8080
+	targetPort: 8080
+}]
 deployment: linecook: spec: template: spec: {
 	volumes: [{
 	}, {

doc/tutorial/kubernetes/quick/services/kitchen/pastrychef/kube.cue

@@ -1,5 +1,9 @@
 package kube
 
+service: pastrychef: spec: ports: [{
+	port:       8080
+	targetPort: 8080
+}]
 deployment: pastrychef: spec: template: spec: {
 	volumes: [{
 	}, {

doc/tutorial/kubernetes/quick/services/kitchen/souschef/kube.cue

@@ -1,5 +1,9 @@
 package kube
 
+service: souschef: spec: ports: [{
+	port:       8080
+	targetPort: 8080
+}]
 deployment: souschef: spec: template: spec: containers: [{
 	image: "gcr.io/myproj/souschef:v0.5.3"
 }]

doc/tutorial/kubernetes/quick/services/mon/alertmanager/kube.cue

@@ -11,7 +11,9 @@ service: alertmanager: {
 	spec: {
 		// type: ClusterIP
 		ports: [{
-			name: "main"
+			name:       "main"
+			port:       9093
+			targetPort: 9093
 		}]
 	}
 }

doc/tutorial/kubernetes/quick/services/mon/nodeexporter/kube.cue

@@ -7,6 +7,7 @@ service: "node-exporter": {
 		clusterIP: "None"
 		ports: [{
 			name: "metrics"
+			port: 9100
 		}]
 	}
 }

doc/tutorial/kubernetes/quick/services/mon/prometheus/kube.cue

@@ -9,6 +9,7 @@ service: prometheus: {
 		type: "NodePort"
 		ports: [{
 			name:     "main"
+			port:     9090
 			nodePort: 30900
 		}]
 	}

doc/tutorial/kubernetes/quick/services/proxy/authproxy/service.cue

@@ -1 +1,6 @@
 package kube
+
+service: authproxy: spec: ports: [{
+	port:       4180
+	targetPort: 4180
+}]

doc/tutorial/kubernetes/quick/services/proxy/goget/service.cue

@@ -4,7 +4,8 @@ service: goget: spec: {
 	type:           "LoadBalancer"
 	loadBalancerIP: "1.3.5.7" // static ip
 	ports: [{
-		port: 443
-		name: "https"
+		port:       443
+		targetPort: 7443
+		name:       "https"
 	}]
 }

doc/tutorial/kubernetes/quick/services/proxy/nginx/service.cue

@@ -4,8 +4,13 @@ service: nginx: spec: {
 	type:           "LoadBalancer"
 	loadBalancerIP: "1.3.4.5"
 	ports: [{
-		name: "http"
+		port: 80 // the port that this service should serve on
+		// the container on each pod to connect to, can be a name
+		// (e.g. 'www') or a number (e.g. 80)
+		targetPort: 80
+		name:       "http"
 	}, {
+		port: 443
 		name: "https"
 	}]
 }

tools/trim/trim.go

@@ -267,26 +267,30 @@ func (t *trimSet) trim(label string, v, m, scope cue.Value) (rmSet []ast.Node) {
 	// Identify generated components and unify them with the mixin value.
 	exists := false
 	for _, v := range vSplit {
-		if src := v.Source(); t.alwaysGen[src] || inNodes(gen, src) {
-			if !v.IsConcrete() {
-				// The template has an expression that cannot be fully
-				// resolved. Attempt to complete the expression by
-				// evaluting it within the struct to which the template
-				// is applied.
-				expr := internal.ToExpr(v.Syntax())
-
-				// TODO: this only resolves references contained in scope.
-				v = internal.EvalExpr(scope, expr).(cue.Value)
-			}
+		src := v.Source()
+		alwaysGen := t.alwaysGen[src]
+		inNodes := inNodes(gen, src)
+		if !(alwaysGen || inNodes) {
+			continue
+		}
+		if !v.IsConcrete() {
+			// The template has an expression that cannot be fully
+			// resolved. Attempt to complete the expression by
+			// evaluting it within the struct to which the template
+			// is applied.
+			expr := internal.ToExpr(v.Syntax())
+
+			// TODO: this only resolves references contained in scope.
+			v = internal.EvalExpr(scope, expr).(cue.Value)
+		}
 
-			if w := in.Unify(v); w.Err() == nil {
-				in = w
-			}
-			// One of the sources of this struct is generated. That means
-			// we can safely delete a non-generated version.
-			exists = true
-			gen = append(gen, src)
+		if w := in.Unify(v); w.Err() == nil {
+			in = w
 		}
+		// One of the sources of this struct is generated. That means
+		// we can safely delete a non-generated version.
+		exists = true
+		gen = append(gen, src)
 	}
 
 	switch v.Kind() {
@@ -371,39 +375,53 @@ func (t *trimSet) trim(label string, v, m, scope cue.Value) (rmSet []ast.Node) {
 
 	case cue.ListKind:
 		mIter, _ := m.List()
+		elem, hasElem := m.Elem()
 		i := 0
 		rmElem := []ast.Node{}
+		allowRemove := true
 		for iter, _ := v.List(); iter.Next(); i++ {
-			mIter.Next()
-			rm := t.trim(strconv.Itoa(i), iter.Value(), mIter.Value(), scope)
+			var m cue.Value
+			if mIter.Next() {
+				m = mIter.Value()
+			} else if hasElem {
+				m = elem
+				allowRemove = false
+			} else {
+				allowRemove = false
+				break
+			}
+			rm := t.trim(strconv.Itoa(i), iter.Value(), m, scope)
 			rmElem = append(rmElem, rm...)
 		}
 
 		// Signal the removal of lists of which all elements have been marked
 		// for removal.
-		for _, v := range vSplit {
-			if src := v.Source(); !t.alwaysGen[src] {
-				l, ok := src.(*ast.ListLit)
-				if !ok {
-					break
-				}
-				rmList := true
-				iter, _ := v.List()
-				for i := 0; i < len(l.Elts) && iter.Next(); i++ {
-					if !inNodes(rmElem, l.Elts[i]) {
-						rmList = false
+		if allowRemove {
+			for _, v := range vSplit {
+				if src := v.Source(); !t.alwaysGen[src] {
+					l, ok := src.(*ast.ListLit)
+					if !ok {
 						break
 					}
-				}
-				if rmList && m.Exists() && t.canRemove(src) && !inNodes(gen, src) {
-					rmSet = append(rmSet, src)
+					rmList := true
+					iter, _ := v.List()
+					for i := 0; i < len(l.Elts) && iter.Next(); i++ {
+						if !inNodes(rmElem, l.Elts[i]) {
+							rmList = false
+							break
+						}
+					}
+					if rmList && m.Exists() && t.canRemove(src) && !inNodes(gen, src) {
+						rmSet = append(rmSet, src)
+					}
 				}
 			}
 		}
 		fallthrough
 
 	default:
 		// Mark any subsumed part that is covered by generated config.
+		in, _ := in.Default()
 		if in.Err() == nil && v.Subsume(in) == nil {
 			for _, v := range vSplit {
 				src := v.Source()