internal/core/export: don't embed proper conjuncts

This now makes the distinction between conjuncts
and embeddings, fixing a bug that resulted from the
slight semantics changes in embeddings introduced in
https://cue-review.googlesource.com/c/cue/+/8229

Note that scalar values can still always be embedded
as it doesn't affect closedness.
Also recersively nested embeddings can be merged.
Nested closed conjunctions need to remain conjunctions.

Change-Id: I14c1a30802132effe0c6c27a4a8e363236df5771
Reviewed-on: https://cue-review.googlesource.com/c/cue/+/8363
Reviewed-by: CUE cueckoo <cueckoo@gmail.com>
Reviewed-by: Marcel van Lohuizen <mpvl@golang.org>

internal/core/export/expr.go

@@ -97,7 +97,7 @@ func (x *exporter) mergeValues(label adt.Feature, src *adt.Vertex, a []conjunct,
 	for _, c := range a {
 		e.top().upCount = c.up
 		x := c.c.Expr()
-		e.addExpr(c.c.Env, x)
+		e.addExpr(c.c.Env, x, false)
 	}
 
 	s := x.top().scope
@@ -109,7 +109,7 @@ func (x *exporter) mergeValues(label adt.Feature, src *adt.Vertex, a []conjunct,
 	// Unify values only for one level.
 	if len(e.values.Conjuncts) > 0 {
 		e.values.Finalize(e.ctx)
-		e.exprs = append(e.exprs, e.value(e.values, e.values.Conjuncts...))
+		e.embed = append(e.embed, e.value(e.values, e.values.Conjuncts...))
 	}
 
 	// Collect and order set of fields.
@@ -135,21 +135,25 @@ func (x *exporter) mergeValues(label adt.Feature, src *adt.Vertex, a []conjunct,
 	})
 
 	if len(e.fields) == 0 && !e.hasEllipsis {
-		switch len(e.exprs) {
+		switch len(e.embed) + len(e.conjuncts) {
 		case 0:
 			if len(e.structs) > 0 {
 				return s
 			}
 			return ast.NewIdent("_")
 		case 1:
-			return e.exprs[0]
+			if len(e.conjuncts) == 1 {
+				return e.conjuncts[0]
+			}
+			return e.embed[0]
 		case 2:
 			// Simplify.
-			return ast.NewBinExpr(token.AND, e.exprs...)
+			e.conjuncts = append(e.conjuncts, e.embed...)
+			return ast.NewBinExpr(token.AND, e.conjuncts...)
 		}
 	}
 
-	for _, x := range e.exprs {
+	for _, x := range e.embed {
 		s.Elts = append(s.Elts, &ast.EmbedDecl{Expr: x})
 	}
 
@@ -201,15 +205,18 @@ func (x *exporter) mergeValues(label adt.Feature, src *adt.Vertex, a []conjunct,
 		return ast.NewCall(ast.NewIdent("close"), s)
 	}
 
-	return s
+	e.conjuncts = append(e.conjuncts, s)
+
+	return ast.NewBinExpr(token.AND, e.conjuncts...)
 }
 
 // Conjuncts if for collecting values of a single vertex.
 type conjuncts struct {
 	*exporter
 	// Values is used to collect non-struct values.
 	values      *adt.Vertex
-	exprs       []ast.Expr
+	embed       []ast.Expr
+	conjuncts   []ast.Expr
 	structs     []*adt.StructInfo
 	fields      map[adt.Feature]field
 	attrs       []*ast.Attribute
@@ -238,7 +245,7 @@ type conjunct struct {
 	up int32
 }
 
-func (e *conjuncts) addExpr(env *adt.Environment, x adt.Expr) {
+func (e *conjuncts) addExpr(env *adt.Environment, x adt.Expr, isEmbed bool) {
 	switch x := x.(type) {
 	case *adt.StructLit:
 		e.top().upCount++
@@ -250,7 +257,7 @@ func (e *conjuncts) addExpr(env *adt.Environment, x adt.Expr) {
 		// Only add if it only has no bulk fields or elipsis.
 		if isComplexStruct(x) {
 			_, saved := e.pushFrame(nil)
-			e.exprs = append(e.exprs, e.adt(x, nil))
+			e.embed = append(e.embed, e.adt(x, nil))
 			e.popFrame(saved)
 			return
 		}
@@ -269,7 +276,7 @@ func (e *conjuncts) addExpr(env *adt.Environment, x adt.Expr) {
 				e.hasEllipsis = true
 				continue
 			case adt.Expr:
-				e.addExpr(env, f)
+				e.addExpr(env, f, true)
 				continue
 
 				// TODO: also handle dynamic fields
@@ -301,7 +308,7 @@ func (e *conjuncts) addExpr(env *adt.Environment, x adt.Expr) {
 					v.MatchAndInsert(e.ctx, v)
 					a = append(a, &ast.Ellipsis{Type: e.expr(v)})
 				}
-				e.exprs = append(e.exprs, ast.NewList(a...))
+				e.embed = append(e.embed, ast.NewList(a...))
 				return
 
 			case *adt.StructMarker:
@@ -322,20 +329,27 @@ func (e *conjuncts) addExpr(env *adt.Environment, x adt.Expr) {
 
 	case *adt.BinaryExpr:
 		switch {
-		case x.Op == adt.AndOp:
-			e.addExpr(env, x.X)
-			e.addExpr(env, x.Y)
+		case x.Op == adt.AndOp && !isEmbed:
+			e.addExpr(env, x.X, false)
+			e.addExpr(env, x.Y, false)
 		case isSelfContained(x):
 			e.values.AddConjunct(adt.MakeRootConjunct(env, x))
 		default:
-			e.exprs = append(e.exprs, e.expr(x))
+			if isEmbed {
+				e.embed = append(e.embed, e.expr(x))
+			} else {
+				e.conjuncts = append(e.conjuncts, e.expr(x))
+			}
 		}
 
 	default:
-		if isSelfContained(x) {
+		switch {
+		case isSelfContained(x):
 			e.values.AddConjunct(adt.MakeRootConjunct(env, x))
-		} else {
-			e.exprs = append(e.exprs, e.expr(x))
+		case isEmbed:
+			e.embed = append(e.embed, e.expr(x))
+		default:
+			e.conjuncts = append(e.conjuncts, e.expr(x))
 		}
 	}
 }

internal/core/export/testdata/adt.txtar

@@ -28,6 +28,18 @@ l1: [3, ...int]
 l2: [...int]
 l3: []
 l4: [1, 2]
+l5: [1, 3] & {
+	[1, 3]
+
+	#foo: int
+}
+
+#foo: int
+l6: [1, #foo] & {
+	[1, 3]
+
+	#foo: int
+}
 
 n1: 1.0
 n10: 10
@@ -48,9 +60,9 @@ e6: !t
 e7: !t || !false
 e8?: !false
 
-m1: {
+m1: {[string]: uint} & {
     // this is a pattern constraint
-    {[string]: int}
+    {[string]: int} & {[string]: int64}
     // foo is an optional field
     foo?: 3
 
@@ -134,6 +146,15 @@ l1: [3, ...int]
 l2: [...int]
 l3: []
 l4: [1, 2]
+l5: [1, 3] & {
+	[1, 3]
+	#foo: int
+}
+#foo: int
+l6:   [1, #foo] & {
+	[1, 3]
+	#foo: int
+}
 n1:  1.0
 n10: 10
 t:   true
@@ -145,9 +166,13 @@ e5:  e1 + e2 - e3
 e6:  !t
 e7:  !t || !false
 e8?: !false
-m1: {
+m1:  {
+	[string]: int & >=0
+} & {
 	{
 		[string]: int
+	} & {
+		[string]: int64
 	}
 
 	// foo is an optional field
@@ -205,6 +230,15 @@ errorListDef: {
 [l4]
 [l4 0]
 [l4 1]
+[l5]
+[l5 #foo]
+[l5 0]
+[l5 1]
+[#foo]
+[l6]
+[l6 #foo]
+[l6 0]
+[l6 1]
 [n1]
 [n10]
 [t]
@@ -281,6 +315,15 @@ _|_ // e3: index out of range [2] with length 2
 	l2: []
 	l3: []
 	l4: [1, 2]
+	l5: {
+		#foo: int
+		[1, 3]
+	}
+	#foo: int
+	l6: {
+		#foo: int
+		[1, 3]
+	}
 	n1:  1.0
 	n10: 10
 

internal/core/export/testdata/docs.txtar

@@ -126,9 +126,7 @@ bar: {
 	// comment from bar on field 2
 	field2: int
 }
-baz: {
-	bar
-
+baz: bar & {
 	// comment from baz on field 1
 	field1: int
 	field2: int

internal/core/export/testdata/hidden.txtar

@@ -22,8 +22,7 @@ package foo
 
 import "acme.com/pkg"
 
-a: {
-	pkg.#A
+a: pkg.#A & {
 	_val:  3
 	_#val: 6
 }

internal/core/export/testdata/issue662.txtar

@@ -11,8 +11,7 @@
 #LineConfig: {
 	lineColor?: string
 }
-#GraphFieldConfig: {
-	#LineConfig
+#GraphFieldConfig: #LineConfig & {
 	drawStyle?: int
 }
 -- out/doc --

internal/core/export/testdata/merge.txtar

@@ -0,0 +1,102 @@
+-- in.cue --
+#A: {
+    _
+	#a: string
+}
+
+#E: {_}
+#F: {_}
+#G: {_}
+
+#B: #A & {
+	{ 2, #def: 3 }
+	2
+	#E & #F
+	#f: int
+    {
+        _
+        #bar: int
+        #G
+    }
+
+}
+-- out/definition --
+#A: {
+	#a: string
+}
+#E: {}
+#F: {}
+#G: {}
+#B: #A & {
+	#E & #F
+	#G
+	2
+	#f:   int
+	#def: 3
+	#bar: int
+}
+-- out/doc --
+[]
+[#A]
+[#A #a]
+[#E]
+[#F]
+[#G]
+[#B]
+[#B #a]
+[#B #def]
+[#B #bar]
+[#B #f]
+-- out/value --
+== Simplified
+{}
+== Raw
+{
+	#A: {
+		#a: string
+	}
+	#E: {}
+	#F: {}
+	#G: {}
+	#B: {
+		2
+		#a:   string
+		#f:   int
+		#def: 3
+		#bar: int
+	}
+}
+== Final
+{}
+== All
+{
+	#A: {
+		#a: string
+	}
+	#E: {}
+	#F: {}
+	#G: {}
+	#B: {
+		2
+		#a:   string
+		#f:   int
+		#def: 3
+		#bar: int
+	}
+}
+== Eval
+{
+	#A: {
+		#a: string
+	}
+	#E: {}
+	#F: {}
+	#G: {}
+	#B: {
+		2
+		#a:   string
+		#f:   int
+		#def: 3
+		#bar: int
+	}
+}