internal/core: expose topological sorting API

Previously, the new topological sorting could only be turned on and off
through the CUE_EXPERIMENT env var.

Add topoSort field to Runtime and OpContext, and populate initially via
CUE_EXPERIMENT. Change export so it looks at OpContext.TopoSort instead
of CUE_EXPERIMENT.

This makes topological sorting configurable in the same way as evaluator
version.

Signed-off-by: Matthew Sackman <[email protected]>
Change-Id: If3cbf748898bf87d1ced7ec014bdf9553a34afe5
Reviewed-on: https://review.gerrithub.io/c/cue-lang/cue/+/1203603
TryBot-Result: CUEcueckoo <[email protected]>
Reviewed-by: Marcel van Lohuizen <[email protected]>

cue/cuecontext/cuecontext_test.go

@@ -21,6 +21,7 @@ import (
 	"cuelang.org/go/cue"
 	"cuelang.org/go/cue/ast"
 	"cuelang.org/go/internal"
+	"cuelang.org/go/internal/core/adt"
 	"cuelang.org/go/internal/core/runtime"
 	"cuelang.org/go/internal/cueexperiment"
 )
@@ -82,7 +83,8 @@ func TestEvalVersion(t *testing.T) {
 	defer func() { cueexperiment.Flags.EvalV3 = saved }()
 
 	test := func(c *cue.Context, want internal.EvaluatorVersion) {
-		got, _ := (*runtime.Runtime)(c).Settings()
+		opCtx := adt.NewContext((*runtime.Runtime)(c), nil)
+		got := opCtx.Version
 		if got != want {
 			t.Errorf("got %v; want %v", got, want)
 		}

internal/core/adt/context.go

@@ -167,7 +167,9 @@ type Runtime interface {
 	// type if available.
 	LoadType(t reflect.Type) (src ast.Expr, expr Expr, ok bool)
 
-	Settings() (internal.EvaluatorVersion, cuedebug.Config)
+	// ConfigureOpCtx configures the [*OpContext] with details such as
+	// evaluator version, debug options etc.
+	ConfigureOpCtx(ctx *OpContext)
 }
 
 type Config struct {
@@ -180,16 +182,15 @@ func New(v *Vertex, cfg *Config) *OpContext {
 	if cfg.Runtime == nil {
 		panic("nil Runtime")
 	}
-	version, flags := cfg.Runtime.Settings()
+
 	ctx := &OpContext{
 		Runtime:     cfg.Runtime,
 		Format:      cfg.Format,
 		vertex:      v,
-		Version:     version,
-		stats:       stats.Counts{EvalVersion: version},
-		Config:      flags,
 		taskContext: schedConfig,
 	}
+	cfg.Runtime.ConfigureOpCtx(ctx)
+	ctx.stats.EvalVersion = ctx.Version
 	if v != nil {
 		ctx.e = &Environment{Up: nil, Vertex: v}
 	}
@@ -213,7 +214,8 @@ type OpContext struct {
 	Format func(Runtime, Node) string
 
 	cuedebug.Config
-	Version internal.EvaluatorVersion // Copied from Runtime
+	Version  internal.EvaluatorVersion // Copied from Runtime
+	TopoSort bool                      // Copied from Runtime
 
 	taskContext
 

internal/core/eval/eval.go

@@ -30,8 +30,6 @@ func Evaluate(r adt.Runtime, v *adt.Vertex) {
 
 func New(r adt.Runtime) *Unifier {
 	ctx := NewContext(r, nil)
-	// TODO: we could access these directly if we can use runtime.Runtime directly.
-	ctx.Version, ctx.Config = r.Settings()
 	return &Unifier{r: r, e: ctx}
 }
 

internal/core/export/toposort.go

@@ -20,7 +20,6 @@ import (
 
 	"cuelang.org/go/internal/core/adt"
 	"cuelang.org/go/internal/core/toposort"
-	"cuelang.org/go/internal/cueexperiment"
 )
 
 // TODO: topological sort should go arguably in a more fundamental place as it
@@ -30,7 +29,7 @@ import (
 // features than for which there are arcs and also includes features for
 // optional fields. It assumes the Structs fields are initialized and evaluated.
 func VertexFeatures(c *adt.OpContext, v *adt.Vertex) []adt.Feature {
-	if cueexperiment.Flags.TopoSort {
+	if c.TopoSort {
 		return toposort.VertexFeatures(c, v)
 	} else {
 		return vertexFeatures(c, v)

internal/core/runtime/runtime.go

@@ -17,6 +17,7 @@ package runtime
 import (
 	"cuelang.org/go/cue/build"
 	"cuelang.org/go/internal"
+	"cuelang.org/go/internal/core/adt"
 	"cuelang.org/go/internal/cuedebug"
 	"cuelang.org/go/internal/cueexperiment"
 )
@@ -31,7 +32,8 @@ type Runtime struct {
 	// the kind in a file-level @extern(kind) attribute.
 	interpreters map[string]Interpreter
 
-	version internal.EvaluatorVersion
+	version  internal.EvaluatorVersion
+	topoSort bool
 
 	flags cuedebug.Config
 }
@@ -40,6 +42,12 @@ func (r *Runtime) Settings() (internal.EvaluatorVersion, cuedebug.Config) {
 	return r.version, r.flags
 }
 
+func (r *Runtime) ConfigureOpCtx(ctx *adt.OpContext) {
+	ctx.Version = r.version
+	ctx.TopoSort = r.topoSort
+	ctx.Config = r.flags
+}
+
 func (r *Runtime) SetBuildData(b *build.Instance, x interface{}) {
 	r.loaded[b] = x
 }
@@ -73,6 +81,12 @@ func (r *Runtime) SetVersion(v internal.EvaluatorVersion) {
 	r.version = v
 }
 
+// SetTopologicalSort sets whether or not to use topological sorting
+// for the Runtime.
+func (r *Runtime) SetTopologicalSort(b bool) {
+	r.topoSort = b
+}
+
 // SetDebugOptions sets the debug flags to use for the Runtime. This should only
 // be set before first use.
 func (r *Runtime) SetDebugOptions(flags *cuedebug.Config) {
@@ -103,4 +117,5 @@ func (r *Runtime) Init() {
 	} else {
 		r.version = internal.DefaultVersion
 	}
+	r.topoSort = cueexperiment.Flags.TopoSort
 }

internal/core/toposort/sort_test.go

@@ -21,18 +21,11 @@ import (
 	"cuelang.org/go/cue/format"
 	"cuelang.org/go/internal/core/eval"
 	"cuelang.org/go/internal/core/export"
-	"cuelang.org/go/internal/cueexperiment"
 	"cuelang.org/go/internal/cuetdtest"
 	"cuelang.org/go/internal/cuetxtar"
 )
 
 func TestTopologicalSort(t *testing.T) {
-	cueexperiment.Init()
-	saved := cueexperiment.Flags.TopoSort
-	defer func() { cueexperiment.Flags.TopoSort = saved }()
-
-	cueexperiment.Flags.TopoSort = true
-
 	test := cuetxtar.TxTarTest{
 		Root:   "testdata",
 		Name:   "toposort",
@@ -41,6 +34,7 @@ func TestTopologicalSort(t *testing.T) {
 
 	test.Run(t, func(t *cuetxtar.Test) {
 		run := t.Runtime()
+		run.SetTopologicalSort(true)
 		inst := t.Instance()
 
 		v, err := run.Build(nil, inst)