internal/core/adt: fix EVAL counter issue

See the various comments in the change for
an explanation of this change.

Signed-off-by: Marcel van Lohuizen <[email protected]>
Change-Id: Ib5da63c457a5061efd9e46733084f6a9c6959456
Reviewed-on: https://review.gerrithub.io/c/cue-lang/cue/+/1207748
Reviewed-by: Matthew Sackman <[email protected]>
TryBot-Result: CUEcueckoo <[email protected]>
Unity-Result: CUE porcuepine <[email protected]>

internal/core/adt/eval_test.go

@@ -78,7 +78,7 @@ var needFix = map[string]string{
 var skipDebugDepErrors = map[string]int{
 	"cycle/disjunction":        1,
 	"cycle/structural":         1,
-	"disjunctions/elimination": 6,
+	"disjunctions/elimination": 4,
 	"eval/issue545":            1,
 	"eval/notify":              3,
 }

internal/core/adt/overlay.go

@@ -351,15 +351,16 @@ func (ctx *overlayContext) initCloneCC(x *closeContext) {
 	o.Patterns = append(o.Patterns, x.Patterns...)
 
 	// needsCloseInSchedule is a separate mechanism to signal nodes that have
-	// completed. Do not signal such nodes if they are outside the current
-	// copied graph.
-	if cx := x.needsCloseInSchedule; cx != nil {
-		if cx.src._cc.overlay == nil {
-			o.needsCloseInSchedule = nil
-		} else {
-			// TODO: Debug assert: cx.overlay != nil
-			o.needsCloseInSchedule = ctx.allocCC(cx)
-		}
+	// completed that corresponds to the EVAL mechanism. Since we have not
+	// processed the conjuncts yet, these are inherently initiated outside of
+	// this conjunct. By now, if a closeContext needs to remain open, other
+	// counters should have been added. As an example, the parent node of this
+	// disjunct is still processing. The disjunction will be fully added before
+	// processing, and thus their will be no direct EVAL dependency. However,
+	// this disjunct may depend on a NOTIFY that is kept open by an ancestor
+	// EVAL.
+	if x.needsCloseInSchedule != nil {
+		o.needsCloseInSchedule = nil
 	}
 
 	// child and next always point to completed closeContexts. Moreover, only
@@ -467,6 +468,13 @@ func (ctx *overlayContext) finishDependencies(x *closeContext) {
 			continue
 		}
 
+		// Since have not started processing the disjunct yet, all EVAL
+		// dependencies will have been initiated outside of this disjunct.
+		if d.kind == EVAL {
+			o.decDependentNoMatch(ctx.ctx, EVAL, nil)
+			continue
+		}
+
 		if d.dependency.overlay == nil {
 			// This dependency is irrelevant for the current overlay. We can
 			// eliminate it as long as we decrement the accompanying counter.