internal/core/adt: more thorough evaluation for scalar values

This gives slightly less useful error messages
in some cases, but at least it resolves in some
cases where before it didn't.

Fixes #3828

Signed-off-by: Marcel van Lohuizen <[email protected]>
Change-Id: I3c2db3f802055fb1290b8d714b8d6a81cb29551d
Reviewed-on: https://review.gerrithub.io/c/cue-lang/cue/+/1211806
Unity-Result: CUE porcuepine <[email protected]>
Reviewed-by: Daniel Martí <[email protected]>
TryBot-Result: CUEcueckoo <[email protected]>

Author: mpvl

cue/testdata/eval/dynamic_field.txtar

@@ -204,9 +204,8 @@ Result:
   issue3828: (struct){
     reduced: (struct){
       a: (struct){
-        b: (_|_){
-          // [incomplete] issue3828.reduced.a.b: key value of dynamic field must be concrete, found _|_(issue3828.reduced.a.b: cycle with field: x):
-          //     ./issue3828.cue:5:5
+        b: (struct){
+          foobot1: (bool){ true }
         }
       }
       str: (string){ "foobot1" }
@@ -219,9 +218,8 @@ Result:
             }
           }
           collaborators: (struct){
-            repo1: (_|_){
-              // [incomplete] issue3828.full.orgs.org1.collaborators.repo1: key value of dynamic field must be concrete, found _|_(issue3828.full.orgs.org1.collaborators.repo1: cycle with field: orgBotUser):
-              //     ./issue3828.cue:18:33
+            repo1: (struct){
+              bot1: (bool){ true }
             }
           }
         }
@@ -264,31 +262,7 @@ diff old new
          }
          #ID: (_|_){
            // [incomplete] noCycleError.foo.bar.#ID: invalid interpolation: non-concrete value string (type string):
-@@ -100,8 +100,9 @@
-   issue3828: (struct){
-     reduced: (struct){
-       a: (struct){
--        b: (struct){
--          foobot1: (bool){ true }
-+        b: (_|_){
-+          // [incomplete] issue3828.reduced.a.b: key value of dynamic field must be concrete, found _|_(issue3828.reduced.a.b: cycle with field: x):
-+          //     ./issue3828.cue:5:5
-         }
-       }
-       str: (string){ "foobot1" }
-@@ -114,8 +115,9 @@
-             }
-           }
-           collaborators: (struct){
--            repo1: (struct){
--              bot1: (bool){ true }
-+            repo1: (_|_){
-+              // [incomplete] issue3828.full.orgs.org1.collaborators.repo1: key value of dynamic field must be concrete, found _|_(issue3828.full.orgs.org1.collaborators.repo1: cycle with field: orgBotUser):
-+              //     ./issue3828.cue:18:33
-             }
-           }
-         }
-@@ -123,6 +125,9 @@
+@@ -123,6 +123,9 @@
        botUser: (string){ "bot1" }
      }
    }
@@ -298,7 +272,7 @@ diff old new
    foo: (struct){
      b: (struct){
        c: (struct){
-@@ -130,7 +135,4 @@
+@@ -130,7 +133,4 @@
        }
      }
    }

internal/core/adt/states.go

@@ -220,7 +220,12 @@ const (
 	// list value.
 	scalarConjunct = allTasksCompleted |
 		scalarKnown |
-		valueKnown
+		valueKnown |
+		disjunctionTask
+
+	// a scalarValue is one that is guaranteed to result in a scalar.
+	// TODO: use more widely instead of scalarKnown.
+	scalarValue = scalarKnown | disjunctionTask
 
 	// needsX condition sets are used to indicate which conditions need to be
 	// met.

internal/core/adt/tasks.go

@@ -145,7 +145,7 @@ func processDynamic(ctx *OpContext, t *task, mode runMode) {
 
 	field := t.x.(*DynamicField)
 
-	v := ctx.scalarValue(t, field.Key)
+	v := ctx.value(field.Key, combineMode(scalarValue, mode))
 	if v == nil {
 		return
 	}
@@ -182,7 +182,7 @@ func processPatternConstraint(ctx *OpContext, t *task, mode runMode) {
 
 	// Note that the result may be a disjunction. Be sure to not take the
 	// default value as we want to retain the options of the disjunction.
-	v := ctx.evalState(field.Filter, require(0, scalarKnown))
+	v := ctx.evalState(field.Filter, require(0, scalarValue))
 	if v == nil {
 		return
 	}

internal/core/export/testdata/main/dynamic.txtar

@@ -137,7 +137,7 @@ bogus field for a failed dynamic field.
 	}
 }
 == Final
-_|_ // key value of dynamic field must be concrete, found string (and 3 more errors)
+_|_ // key value of dynamic field must be concrete, found _|_(cycle error) (and 3 more errors)
 == All
 {
 	x:     string
@@ -243,7 +243,7 @@ diff old new
 +}
  == Final
 -_|_ // invalid non-ground value string (must be concrete string) (and 1 more errors)
-+_|_ // key value of dynamic field must be concrete, found string (and 3 more errors)
++_|_ // key value of dynamic field must be concrete, found _|_(cycle error) (and 3 more errors)
  == All
 -_|_ // invalid non-ground value string (must be concrete string) (and 1 more errors)
 +{