internal/core/adt: fix bug in notification

Node should be directly scheduled, instead of being
added as an arc. This is now fixed. Note that this
change now mimics how the old evaluator worked.

Note that the test output changed. Even though the
errors are now reported elsewhere, it does not
materially change the output. If nothing else, it
is now more analogous to eval V2.

Note that the newly added test has counter issues,
and thus a new line in the counter issue list was
added. This is likely related to a pre-exisiting
condition.

Fixes #3437

Signed-off-by: Marcel van Lohuizen <[email protected]>
Change-Id: I0dae66eedfd488375225a7697e623c6e8e1c916b
Reviewed-on: https://review.gerrithub.io/c/cue-lang/cue/+/1202773
TryBot-Result: CUEcueckoo <[email protected]>
Reviewed-by: Daniel Martí <[email protected]>
Unity-Result: CUE porcuepine <[email protected]>

cue/testdata/cycle/chain.txtar

@@ -208,21 +208,25 @@ issue2052: full: {
 	d: #Depth & {#in: tree}
 }
 -- out/evalalpha/stats --
-Leaks:  13628
-Freed:  1534
-Reused: 1533
-Allocs: 13629
+Leaks:  12701
+Freed:  1308
+Reused: 1307
+Allocs: 12702
 Retain: 0
 
-Unifications: 5379
-Conjuncts:    72236
-Disjuncts:    9483
+Unifications: 5010
+Conjuncts:    66031
+Disjuncts:    8699
 -- out/evalalpha --
 Errors:
 issue2052.t1.#Depth: adding field #basic not allowed as field set was already referenced:
     ./issue2052.cue:8:20
+issue2052.t1.d: adding field #basic not allowed as field set was already referenced:
+    ./issue2052.cue:8:20
 issue2052.t2.#Depth: adding field #basic not allowed as field set was already referenced:
     ./issue2052.cue:41:20
+issue2052.t2.d: adding field #basic not allowed as field set was already referenced:
+    ./issue2052.cue:41:20
 
 Result:
 (_|_){
@@ -316,7 +320,9 @@ Result:
         }
       }
       tree: (string){ "bar" }
-      d: (#struct){
+      d: (_|_){
+        // [eval] issue2052.t1.d: adding field #basic not allowed as field set was already referenced:
+        //     ./issue2052.cue:8:20
         #in: (string){ "bar" }
         #maxiter: (int){ 4 }
         #funcs: (#struct){
@@ -342,8 +348,6 @@ Result:
             out: (int){ 1 }
           }
         }
-        #basic: ((null|string)){ |((string){ string }, (null){ null }) }
-        out: (int){ 1 }
       }
     }
     t2: (_|_){
@@ -385,7 +389,9 @@ Result:
         }
       }
       tree: (string){ "bar" }
-      d: (#struct){
+      d: (_|_){
+        // [eval] issue2052.t2.d: adding field #basic not allowed as field set was already referenced:
+        //     ./issue2052.cue:41:20
         #in: (string){ "bar" }
         #maxiter: (int){ 4 }
         #funcs: (#struct){
@@ -411,8 +417,6 @@ Result:
             out: (int){ 1 }
           }
         }
-        #basic: ((null|string)){ |((string){ string }, (null){ null }) }
-        out: (int){ 1 }
       }
     }
     full: (struct){
@@ -725,37 +729,41 @@ diff old new
 -Reused: 1816
 -Allocs: 70
 -Retain: 169
-+Leaks:  13628
-+Freed:  1534
-+Reused: 1533
-+Allocs: 13629
++Leaks:  12701
++Freed:  1308
++Reused: 1307
++Allocs: 12702
 +Retain: 0
 
 -Unifications: 801
 -Conjuncts:    3177
 -Disjuncts:    1979
-+Unifications: 5379
-+Conjuncts:    72236
-+Disjuncts:    9483
++Unifications: 5010
++Conjuncts:    66031
++Disjuncts:    8699
 -- diff/-out/evalalpha<==>+out/eval --
 diff old new
 --- old
 +++ new
-@@ -1,4 +1,12 @@
+@@ -1,4 +1,16 @@
 -(struct){
 +Errors:
 +issue2052.t1.#Depth: adding field #basic not allowed as field set was already referenced:
 +    ./issue2052.cue:8:20
++issue2052.t1.d: adding field #basic not allowed as field set was already referenced:
++    ./issue2052.cue:8:20
 +issue2052.t2.#Depth: adding field #basic not allowed as field set was already referenced:
 +    ./issue2052.cue:41:20
++issue2052.t2.d: adding field #basic not allowed as field set was already referenced:
++    ./issue2052.cue:41:20
 +
 +Result:
 +(_|_){
 +  // [eval]
    chain: (struct){
      t1: (struct){
        #maxiter: (int){ 2 }
-@@ -27,15 +35,11 @@
+@@ -27,15 +39,11 @@
            }
          }
        }
@@ -776,7 +784,7 @@ diff old new
            }
          }
          X: (int){ 1 }
-@@ -51,148 +55,148 @@
+@@ -51,148 +59,148 @@
        }
      }
    }
@@ -915,6 +923,8 @@ diff old new
 -          }
 -        }
 -        #in: (string){ "bar" }
+-        #basic: ((null|string)){ |((string){ string }, (null){ null }) }
+-        out: (int){ 1 }
 +  issue2052: (_|_){
 +    // [eval]
 +    t1: (_|_){
@@ -956,7 +966,9 @@ diff old new
 +        }
 +      }
 +      tree: (string){ "bar" }
-+      d: (#struct){
++      d: (_|_){
++        // [eval] issue2052.t1.d: adding field #basic not allowed as field set was already referenced:
++        //     ./issue2052.cue:8:20
 +        #in: (string){ "bar" }
 +        #maxiter: (int){ 4 }
 +        #funcs: (#struct){
@@ -982,8 +994,6 @@ diff old new
 +            out: (int){ 1 }
 +          }
 +        }
-+        #basic: ((null|string)){ |((string){ string }, (null){ null }) }
-+        out: (int){ 1 }
 +      }
 +    }
 +    t2: (_|_){
@@ -1025,7 +1035,9 @@ diff old new
 +        }
 +      }
 +      tree: (string){ "bar" }
-+      d: (#struct){
++      d: (_|_){
++        // [eval] issue2052.t2.d: adding field #basic not allowed as field set was already referenced:
++        //     ./issue2052.cue:41:20
 +        #in: (string){ "bar" }
 +        #maxiter: (int){ 4 }
 +        #funcs: (#struct){
@@ -1051,8 +1063,6 @@ diff old new
 +            out: (int){ 1 }
 +          }
 +        }
-         #basic: ((null|string)){ |((string){ string }, (null){ null }) }
-         out: (int){ 1 }
        }
      }
      full: (struct){
@@ -1062,7 +1072,7 @@ diff old new
          #maxiter: (int){ |(*(int){ 4 }, (int){ &(>=0, int) }) }
          #funcFactory: (#struct){
            #next: (_){ _ }
-@@ -339,49 +343,7 @@
+@@ -339,49 +347,7 @@
          }
          cow: (string){ "moo" }
        }
@@ -1113,7 +1123,7 @@ diff old new
          #in: (#struct){
            a: (#struct){
              foo: (string){ "bar" }
-@@ -393,6 +355,142 @@
+@@ -393,6 +359,142 @@
            }
            cow: (string){ "moo" }
          }