cue/encoding/jsonschema: fix staticcheck errors

This fixes various errors found by staticcheck:

  - an unused method is removed
  - various usages of cue.Runtime are replaced by cue.Context
  - the default case of a switch statement is moved to be last

Updates #2480.

Signed-off-by: Noam Dolovich <noam.tzvi.dolovich@gmail.com>
Change-Id: I0945d3c63fcd581aa7a6f198bc74fc1a56841b5c
Reviewed-on: https://review.gerrithub.io/c/cue-lang/cue/+/1196248
Unity-Result: CUE porcuepine <cue.porcuepine@gmail.com>
TryBot-Result: CUEcueckoo <cueckoo@cuelang.org>
Reviewed-by: Daniel Martí <mvdan@mvdan.cc>

encoding/jsonschema/decode.go

@@ -76,7 +76,11 @@ func (d *decoder) decode(v cue.Value) *ast.File {
 		if ref == nil {
 			return f
 		}
-		i, err := v.Lookup(ref...).Fields()
+		var selectors []cue.Selector
+		for _, r := range ref {
+			selectors = append(selectors, cue.Str(r))
+		}
+		i, err := v.LookupPath(cue.MakePath(selectors...)).Fields()
 		if err != nil {
 			d.errs = errors.Append(d.errs, errors.Promote(err, ""))
 			return nil
@@ -198,10 +202,6 @@ func (d *decoder) uint(n cue.Value) ast.Expr {
 	return n.Syntax(cue.Final()).(ast.Expr)
 }
 
-func (d *decoder) bool(n cue.Value) ast.Expr {
-	return n.Syntax(cue.Final()).(ast.Expr)
-}
-
 func (d *decoder) boolValue(n cue.Value) bool {
 	x, err := n.Bool()
 	if err != nil {

encoding/jsonschema/decode_test.go

@@ -29,6 +29,7 @@ import (
 
 	"cuelang.org/go/cue"
 	"cuelang.org/go/cue/ast"
+	"cuelang.org/go/cue/cuecontext"
 	"cuelang.org/go/cue/errors"
 	"cuelang.org/go/cue/format"
 	"cuelang.org/go/cue/token"
@@ -68,18 +69,26 @@ func TestDecode(t *testing.T) {
 				}
 			}
 
-			r := &cue.Runtime{}
-			var in *cue.Instance
+			ctx := cuecontext.New()
+			var v cue.Value
 			var out, errout []byte
 			outIndex := -1
 			errIndex := -1
 
 			for i, f := range a.Files {
 				switch path.Ext(f.Name) {
 				case ".json":
-					in, err = json.Decode(r, f.Name, f.Data)
+					expr, err := json.Extract(f.Name, f.Data)
+					if err != nil {
+						t.Fatal(err)
+					}
+					v = ctx.BuildExpr(expr)
 				case ".yaml":
-					in, err = yaml.Decode(r, f.Name, f.Data)
+					file, err := yaml.Extract(f.Name, f.Data)
+					if err != nil {
+						t.Fatal(err)
+					}
+					v = ctx.BuildFile(file)
 				case ".cue":
 					out = f.Data
 					outIndex = i
@@ -94,7 +103,7 @@ func TestDecode(t *testing.T) {
 
 			updated := false
 
-			expr, err := Extract(in, cfg)
+			expr, err := Extract(v, cfg)
 			if err != nil {
 				got := []byte(errors.Details(err, nil))
 
@@ -120,7 +129,8 @@ func TestDecode(t *testing.T) {
 
 				// verify the generated CUE.
 				if !bytes.Contains(a.Comment, []byte("#noverify")) {
-					if _, err = r.Compile(fullpath, b); err != nil {
+					v := ctx.CompileBytes(b, cue.Filename(fullpath))
+					if err := v.Err(); err != nil {
 						t.Fatal(errors.Details(err, nil))
 					}
 				}
@@ -160,26 +170,28 @@ func TestX(t *testing.T) {
 
 	a := txtar.Parse([]byte(data))
 
-	r := &cue.Runtime{}
-	var in *cue.Instance
+	ctx := cuecontext.New()
+	var v cue.Value
 	var err error
 	for _, f := range a.Files {
 		switch path.Ext(f.Name) {
 		case ".json":
-			in, err = json.Decode(r, f.Name, f.Data)
+			expr, err := json.Extract(f.Name, f.Data)
 			if err != nil {
 				t.Fatal(err)
 			}
+			v = ctx.BuildExpr(expr)
 		case ".yaml":
-			in, err = yaml.Decode(r, f.Name, f.Data)
+			file, err := yaml.Extract(f.Name, f.Data)
 			if err != nil {
 				t.Fatal(err)
 			}
+			v = ctx.BuildFile(file)
 		}
 	}
 
 	cfg := &Config{ID: "test"}
-	expr, err := Extract(in, cfg)
+	expr, err := Extract(v, cfg)
 	if err != nil {
 		t.Fatal(err)
 	}

encoding/jsonschema/ref.go

@@ -265,9 +265,6 @@ func (s *state) getNextSelector(v cue.Value, a []string) (l label, tail []string
 
 		return label{a[1], false}, a[2:]
 
-	default:
-		return label{elem, false}, a[1:]
-
 	case "additionalProperties",
 		"patternProperties",
 		"items",
@@ -278,6 +275,9 @@ func (s *state) getNextSelector(v cue.Value, a []string) (l label, tail []string
 
 		// Other known fields cannot be supported.
 		return label{}, nil
+
+	default:
+		return label{elem, false}, a[1:]
 	}
 }