internal/core/adt: initialize erroneous optional fields in disjunctions

When cloning nodeContexts for disjunctions, they
must already be initialized to ensure that the
closeContext counters stay aligned (especially
EVAL). This was enforced by initArcs.
initArcs, however, assumed that an error in an arc
implied an error in the enclosing arc. This is not true
for optional fields. It should therefore still process
remaining arcs in these cases. To be safe, we do so
for any arc that is not a regular field.

Fixes #3680

Signed-off-by: Marcel van Lohuizen <[email protected]>
Change-Id: I90763234472ba29c57d71725b57a39186b521458
Reviewed-on: https://gerrithub.io/c/cue-lang/cue/+/1207263
TryBot-Result: CUEcueckoo <[email protected]>
Unity-Result: CUE porcuepine <[email protected]>
Reviewed-by: Daniel Martí <[email protected]>

Author: mpvl

cue/testdata/disjunctions/incomplete.txtar

@@ -49,16 +49,31 @@ issue782: {
 		interpolation: "override"
 	}
 }
+-- issue3680.cue --
+issue3680: t1: {
+	{} | {
+		a?: _|_
+		b?: _|_
+	}
+	{} | {}
+}
+issue3680: t2: {
+	x:	{} | {
+		a?: _|_
+		b?: _|_
+	}
+	x:	{} | {}
+}
 -- out/eval/stats --
 Leaks:  0
-Freed:  70
-Reused: 64
-Allocs: 6
+Freed:  98
+Reused: 88
+Allocs: 10
 Retain: 0
 
-Unifications: 40
-Conjuncts:    99
-Disjuncts:    70
+Unifications: 56
+Conjuncts:    132
+Disjuncts:    98
 -- out/eval --
 (struct){
   issue700: (struct){
@@ -134,6 +149,32 @@ Disjuncts:    70
       interpolation: (string){ "override" }
     }
   }
+  issue3680: (struct){
+    t1: (struct){ |((struct){
+      }, (struct){
+        a?: (_|_){
+          // [user] explicit error (_|_ literal) in source:
+          //     ./issue3680.cue:3:7
+        }
+        b?: (_|_){
+          // [user] explicit error (_|_ literal) in source:
+          //     ./issue3680.cue:4:7
+        }
+      }) }
+    t2: (struct){
+      x: (struct){ |((struct){
+        }, (struct){
+          a?: (_|_){
+            // [user] explicit error (_|_ literal) in source:
+            //     ./issue3680.cue:10:7
+          }
+          b?: (_|_){
+            // [user] explicit error (_|_ literal) in source:
+            //     ./issue3680.cue:11:7
+          }
+        }) }
+    }
+  }
 }
 -- out/compile --
 --- in.cue
@@ -186,3 +227,24 @@ Disjuncts:    70
     }
   }
 }
+--- issue3680.cue
+{
+  issue3680: {
+    t1: {
+      ({}|{
+        a?: _|_(explicit error (_|_ literal) in source)
+        b?: _|_(explicit error (_|_ literal) in source)
+      })
+      ({}|{})
+    }
+  }
+  issue3680: {
+    t2: {
+      x: ({}|{
+        a?: _|_(explicit error (_|_ literal) in source)
+        b?: _|_(explicit error (_|_ literal) in source)
+      })
+      x: ({}|{})
+    }
+  }
+}

internal/core/adt/disjunct2.go

@@ -241,16 +241,19 @@ func (n *nodeContext) scheduleDisjunction(d envDisjunct) {
 }
 
 func initArcs(ctx *OpContext, v *Vertex) bool {
+	ok := true
 	for _, a := range v.Arcs {
 		s := a.getState(ctx)
 		if s != nil && s.errs != nil {
-			return false
-		}
-		if !initArcs(ctx, a) {
-			return false
+			ok = false
+			if a.ArcType == ArcMember {
+				break
+			}
+		} else if !initArcs(ctx, a) {
+			ok = false
 		}
 	}
-	return true
+	return ok
 }
 
 func (n *nodeContext) processDisjunctions() *Bottom {