internal/cuedebug: drop openinline flag

The two Unity projects which prompted us to originally introduce
the openinline flag for backwards compatibility with evalv2
were github.com/tmm1/taxes.cue and Judson's private project.
As of master today, the former passes entirely, and the latter passes
with the work-in-progress change at https://cuelang.org/cl/1212514.

Given the above, the openinline flag should no longer be used by anyone,
and leaving it around may just cause confusion down the line
for both CUE users and maintainers.

As further proof that the option is no longer needed,
both issue3688.txtar and openinline.txtar are entirely unchanged.

See #3688.

Signed-off-by: Daniel Martí <[email protected]>
Change-Id: Ia6945ba7dd992d8467fa25f61ce01b8af030c270
Reviewed-on: https://review.gerrithub.io/c/cue-lang/cue/+/1213042
Unity-Result: CUE porcuepine <[email protected]>
Reviewed-by: Marcel van Lohuizen <[email protected]>
TryBot-Result: CUEcueckoo <[email protected]>

Author: mvdan

cue/testdata/eval/issue3688.txtar

@@ -1,5 +1,5 @@
-# This test is important in locking in the behaviour of the now-defalut
-# CUE_DEBUG=openinline=0.
+# This test is important in locking in the behaviour of evalv3,
+# which fixed some closedness bugs present in the older evalv2.
 
 -- x.cue --
 package x

cue/testdata/eval/openinline.txtar

@@ -1,4 +1,7 @@
-#openInline: true
+# This test is important in locking in the closedness behavior
+# of evalv2, where inline structs cause some closedness errors
+# to be ignored. evalv3 mimics this behavior for the sake of
+# backwards compatibility and not breaking existing users.
 
 -- cue.mod/module.cue --
 module: "mod.test"

internal/core/adt/conjunct.go

@@ -41,18 +41,6 @@ func (n *nodeContext) scheduleConjunct(c Conjunct, id CloseInfo) {
 	if c.CloseInfo.FromDef {
 		n.node.ClosedRecursive = true
 	}
-	// NOTE: the check for OpenInline is not strictly necessary, but it
-	// clarifies that using id.FromEmbed is not used when OpenInline is not
-	// used.
-	// TODO(dynclose): we have disabled OpenInline for the new dynamic
-	// closedness to be more inline with V2 and because it works slightly
-	// differently. Consider reinstating this in some shape or form.
-	// if c.CloseInfo.FromEmbed || (n.ctx.OpenInline && id.FromEmbed) {
-	// 	if !n.ctx.OpenInline {
-	// 		c.CloseInfo.FromEmbed = false
-	// 		id.FromEmbed = false
-	// 	}
-	// }
 
 	// TODO: consider setting this as a safety measure.
 	// if c.CloseInfo.CycleType > id.CycleType {

internal/core/adt/context.go

@@ -162,11 +162,6 @@ type OpContext struct {
 	// enabled.
 	inConstraint int
 
-	// inLiteralSelectee indicates that we are evaluating a literal struct
-	// as the receiver of a selector. This is used to turn off closedness
-	// checking in compatibility mode.
-	inLiteralSelectee int
-
 	// inDetached indicates that inline structs evaluated in the current context
 	// should never be shared. This is the case, for instance, with the source
 	// for the for clause in a comprehension.
@@ -1070,14 +1065,6 @@ func (c *OpContext) node(orig Node, x Expr, scalar bool, state combinedFlags) *V
 		defer func() { c.ci.FromDef = saved }()
 	}
 
-	if c.OpenInline {
-		if _, ok := x.(Resolver); !ok {
-			c.ci.FromEmbed = true
-			c.inLiteralSelectee++
-			defer func() { c.inLiteralSelectee-- }()
-		}
-	}
-
 	// TODO: always get the vertex. This allows a whole bunch of trickery
 	// down the line.
 	v := c.unifyNode(x, state)

internal/core/adt/eval_test.go

@@ -139,11 +139,6 @@ func skipFiles(a ...*ast.File) (reason string) {
 }
 
 func runEvalTest(t *cuetxtar.Test, version internal.EvaluatorVersion, flags cuedebug.Config) (errorCount int) {
-	// If #openInline is set, override the default as set by the cuedebug package.
-	if s, ok := t.Value("openInline"); ok {
-		flags.OpenInline = s == "true"
-	}
-
 	a := t.Instance()
 	r := runtime.NewWithSettings(version, flags)
 
@@ -220,8 +215,7 @@ func TestX(t *testing.T) {
 
 	flags := cuedebug.Config{
 		Sharing: true, // Uncomment to turn sharing off.
-		// OpenInline: true,
-		LogEval: 1, // Uncomment to turn logging off
+		LogEval: 1,    // Uncomment to turn logging off
 	}
 
 	version := internal.DefaultVersion

internal/core/adt/fields.go

@@ -370,12 +370,6 @@ func (ctx *OpContext) addPositions(c Conjunct) {
 // notAllowedError reports a field not allowed error in n and sets the value
 // for arc f to that error.
 func (ctx *OpContext) notAllowedError(arc *Vertex) *Bottom {
-	// TODO(compat): ultimately we should strive to remove this explicit
-	// reproduction of a bug to ensure compatibility with the old evaluator.
-	if ctx.inLiteralSelectee > 0 {
-		return nil
-	}
-
 	defer ctx.PopArc(ctx.PushArc(arc))
 
 	defer ctx.ReleasePositions(ctx.MarkPositions())

internal/cuedebug/cuedebug.go

@@ -42,30 +42,6 @@ type Config struct {
 	// lexicographically.
 	SortFields bool
 
-	// OpenInline permits disallowed fields to be selected into literal structs
-	// that would normally result in a close error. For instance,
-	//
-	//    #D: {a: 1}
-	//    x: (#D & {b: 2}).b // allow this
-	//
-	// This behavior was erroneously permitted in the v2 evaluator and was fixed
-	// in v3. This allows users that rely on this behavior to use v3. This
-	// option also discards closedness of the resulting expression. As was
-	// reported in Issue #3534, this was another erroneous behavior in v2 that
-	// is otherwise fixed in v3.
-	//
-	// To aid the transition to v3, this is enabled by default for now.
-	//
-	// A possible solution for both incompatibilities would be the introduction
-	// of an openAll builtin to recursive open up a cue value. For the first
-	// issue, the example above could be rewritten as:
-	//
-	//     x: (openAll(#D) & {b: 2}).b
-	//
-	// For the second issue, to open up the entire result of an inline struct,
-	// such an expression could be written as `openAll(expr).out`.
-	OpenInline bool
-
 	// OpenDef disables the check for closedness of definitions.
 	OpenDef bool
 }