encoding/openapi: bug fixes in expandReference
- indirect the reference, but avoid premature
expansion of a disjunction
- intercept infinite recursion so that a proper
error message (with location) can be given.
- allow "type" to be unspecified. This was
incorrectly assumed to be a required field.
Issue #56
Change-Id: Icc543cb626e3533305e73a0867a567c19daf8d2e
Reviewed-on: https://cue-review.googlesource.com/c/cue/+/2682
Reviewed-by: Marcel van Lohuizen <mpvl@golang.org>
diff --git a/encoding/openapi/build.go b/encoding/openapi/build.go
index bf50916..70ab78c 100644
--- a/encoding/openapi/build.go
+++ b/encoding/openapi/build.go
@@ -39,6 +39,7 @@
nameFunc func(inst *cue.Instance, path []string) string
descFunc func(v cue.Value) string
fieldFilter *regexp.Regexp
+ evalDepth int // detect cycles when resolving references
schemas *OrderedMap
@@ -142,11 +143,6 @@
return strings.HasSuffix(name, "_value")
}
-// shouldExpand reports is the given identifier is not exported.
-func (c *buildContext) shouldExpand(p *cue.Instance, ref []string) bool {
- return c.expandRefs
-}
-
func (b *builder) failf(v cue.Value, format string, args ...interface{}) {
panic(&openapiError{
errors.NewMessage(format, args),
@@ -187,13 +183,31 @@
return schema
}
+func resolve(v cue.Value) cue.Value {
+ switch op, a := v.Expr(); op {
+ case cue.SelectorOp:
+ field, _ := a[1].String()
+ v = resolve(a[0]).Lookup(field)
+ }
+ return v
+}
+
func (b *builder) value(v cue.Value, f typeFunc) (isRef bool) {
count := 0
disallowDefault := false
var values cue.Value
- p, a := v.Reference()
- if b.ctx.shouldExpand(p, a) {
- values = v
+ if b.ctx.expandRefs {
+ // Cycles are not allowed when expanding references. Right now we just
+ // cap the depth of evaluation at 30.
+ // TODO: do something more principled.
+ const maxDepth = 30
+ if b.ctx.evalDepth > maxDepth {
+ b.failf(v, "maximum stack depth of %d reached", maxDepth)
+ }
+ b.ctx.evalDepth++
+ defer func() { b.ctx.evalDepth-- }()
+
+ values = resolve(v)
count = 1
} else {
dedup := map[string]bool{}
@@ -844,12 +858,10 @@
func (b *builder) finish() *oaSchema {
switch len(b.allOf) {
case 0:
- if b.typ == "" {
- b.failf(cue.Value{}, "no type specified at finish")
- return nil
- }
t := &OrderedMap{}
- setType(t, b)
+ if b.typ != "" {
+ setType(t, b)
+ }
return t
case 1:
