internal/core/adt: hoist dependency code

It is important that the dependency handling code
is called after all allocations of closeContext have
been called. We are not aware that the allocCC
called in initCloneCC actually allocates new ones,
but just to be sure.

Signed-off-by: Marcel van Lohuizen <[email protected]>
Change-Id: I29873c2f21df1e5d7b143433440be08b7e4f75ed
Reviewed-on: https://review.gerrithub.io/c/cue-lang/cue/+/1207454
Unity-Result: CUE porcuepine <[email protected]>
TryBot-Result: CUEcueckoo <[email protected]>
Reviewed-by: Daniel Martí <[email protected]>

Author: mpvl

internal/core/adt/overlay.go

@@ -97,6 +97,10 @@ func (ctx *overlayContext) cloneRoot(root *nodeContext) *nodeContext {
 		ctx.initCloneCC(cc)
 	}
 
+	for _, cc := range ctx.closeContexts {
+		ctx.finishDependencies(cc)
+	}
+
 	// TODO: walk overlay vertices and decrement counters of non-disjunction
 	// running tasks?
 	// TODO: find a faster way to do this. Walking over vertices would
@@ -380,37 +384,6 @@ func (ctx *overlayContext) initCloneCC(x *closeContext) {
 		// panic("unexpected overlay in next")
 	}
 
-	for _, d := range x.dependencies {
-		if d.decremented {
-			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.
-			if o.conjunctCount < 2 {
-				// This node can only be relevant if it has at least one other
-				// dependency. Check that we are not decrementing the counter
-				// to 0.
-				// TODO: this currently panics for some tests. Disabling does
-				// not seem to harm, though. Reconsider whether this is an issue.
-				// panic("unexpected conjunctCount: must be at least 2")
-			}
-			o.conjunctCount--
-			continue
-		}
-
-		dep := d.dependency
-		if dep.overlay != nil {
-			dep = dep.overlay
-		}
-		o.dependencies = append(o.dependencies, &ccDep{
-			dependency:  dep,
-			kind:        d.kind,
-			decremented: false,
-		})
-	}
-
 	switch p := x.parentConjuncts.(type) {
 	case *closeContext:
 		if p.overlay == nil {
@@ -462,6 +435,41 @@ func (ctx *overlayContext) initCloneCC(x *closeContext) {
 	// be resolved in the base anyway.
 }
 
+func (ctx *overlayContext) finishDependencies(x *closeContext) {
+	o := x.overlay
+
+	for _, d := range x.dependencies {
+		if d.decremented {
+			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.
+			if o.conjunctCount < 2 {
+				// This node can only be relevant if it has at least one other
+				// dependency. Check that we are not decrementing the counter
+				// to 0.
+				// TODO: this currently panics for some tests. Disabling does
+				// not seem to harm, though. Reconsider whether this is an issue.
+				// panic("unexpected conjunctCount: must be at least 2")
+			}
+			o.conjunctCount--
+			continue
+		}
+
+		dep := d.dependency
+		if dep.overlay != nil {
+			dep = dep.overlay
+		}
+		o.dependencies = append(o.dependencies, &ccDep{
+			dependency:  dep,
+			kind:        d.kind,
+			decremented: false,
+		})
+	}
+}
+
 func (ctx *overlayContext) cloneScheduler(dst, src *nodeContext) {
 	ss := &src.scheduler
 	ds := &dst.scheduler