encoding/jsonschema: fix panic on impossible enum

When all possible values of an enum are excluded by the allowed types we were invoking s.all.add with a nil expression which resulted in a panic. Fix that by avoiding adding the constraint in that case: the allowedTypes logic will catch the "impossible constraint" option when finalize is called. Signed-off-by: Roger Peppe <[email protected]> Change-Id: I0836d0444a24df62f6392261a5d5733387529ff6 Reviewed-on: https://review.gerrithub.io/c/cue-lang/cue/+/1199410 Reviewed-by: Daniel Martí <[email protected]> Unity-Result: CUE porcuepine <[email protected]> TryBot-Result: CUEcueckoo <[email protected]>
cue-lang · Aug 13, 2024 · 4760f3b · 4760f3b
1 parent 6694c55
commit 4760f3b
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diff --git a/encoding/jsonschema/constraints.go b/encoding/jsonschema/constraints.go
@@ -204,7 +204,9 @@ var constraints = []*constraint{
 		}
 		s.knownTypes &= types
 		s.allowedTypes &= types
-		s.all.add(n, ast.NewBinExpr(token.OR, a...))
+		if len(a) > 0 {
+			s.all.add(n, ast.NewBinExpr(token.OR, a...))
+		}
 	}),
 
 	// TODO: only allow for OpenAPI.

diff --git a/encoding/jsonschema/testdata/enumexcluded.txtar b/encoding/jsonschema/testdata/enumexcluded.txtar
@@ -0,0 +1,8 @@
+-- type.json --
+{
+  "type": "object",
+  "enum": ["x"]
+}
+-- out/decode/err --
+constraints are not possible to satisfy:
+    type.json:1:1