"segmentation violation" on circular reference used

[gavvvr]

Hello. Here is the minimal example to reproduce the issue:

{
    "openapi": "3.1.0",
    "components": {
        "schemas": {
            "BadCircularElement": {
                "$ref": "#/components/schemas/BadCircularElement"
            },
            "ElementWithUsage": {
                "type": "object",
                "properties": {
                    "somProp": {
                        "oneOf": [
                            {
                                "type": "null"
                            },
                            {
                                "items": {
                                    "$ref": "#/components/schemas/BadCircularElement"
                                },
                                "type": "array"
                            }
                        ]
                    }
                }
            }
        }
    }
}

openapi-changes summary openapi.json openapi.json will fail with the following error:

openapi-changes version: 0.0.76 | compiled: Wed, 26 Feb 2025 01:54:49 UTC

▀  starting work. (0s)panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x2 addr=0x0 pc=0x104cb17c4]

goroutine 182 [running]:
github.com/pb33f/libopenapi/index.(*CircularReferenceResult).GenerateJourneyPath(0x14000211ae0?)
        /home/runner/go/pkg/mod/github.com/pb33f/[email protected]/index/circular_reference_result.go:24 +0x24
github.com/pb33f/libopenapi/datamodel/low.LocateRefNodeWithContext({0x1056ff0b0, 0x14000298330}, 0x140002486e0, 0x14000254008)
        /home/runner/go/pkg/mod/github.com/pb33f/[email protected]/datamodel/low/extraction_functions.go:100 +0x310
github.com/pb33f/libopenapi/datamodel/low/base.buildSchema({0x1056ff0b0, 0x14000298330}, 0x1400062f960, 0x14000248640, 0x140002486e0, 0x1400062f7a0, 0x14000254008)
        /home/runner/go/pkg/mod/github.com/pb33f/[email protected]/datamodel/low/base/schema.go:1201 +0x34c
created by github.com/pb33f/libopenapi/datamodel/low/base.(*Schema).Build in goroutine 106
        /home/runner/go/pkg/mod/github.com/pb33f/[email protected]/datamodel/low/base/schema.go:891 +0x2c94

At the same time vacuum tool will report the problem with no panic `./vacuum lint -b -d -e openapi.json:

/Users/user/Downloads/openapi.json
----------------------------------
Location           | Severity | Message                                                                             | Rule                 | Category | Path
openapi.json:4:20  | error    | infinite circular reference detected: BadCircularElement: BadCircularElement -> ... | resolving-references | Schemas  | BadCircularElement -> BadCircularElement
openapi.json:5:13  | error    | build schema failed: circular reference 'BadCircularElement -> BadCircularElemen... | schema-build-failure | Schemas  | $.components.schemas['BadCircularElement']
openapi.json:17:33 | error    | build schema failed: circular reference 'BadCircularElement -> BadCircularElemen... | schema-build-failure | Schemas  | $.components.schemas['ElementWithUsage'].properties['somProp...

[daveshanley]

Oh dear, this is actually a bug in libopenapi (github.com/pb33f/libopenapi/). Willfix.

[gavvvr]

This sounds a bit surprising, since vacuum is also using libopenapi 😯 UPD: Oh, I should've read the stacktrace 🤦🏻‍♂️

[daveshanley]

libopenapi is still pre v1, it's got some glitches still that need working out before we hit that milestone :)

[daveshanley]

This is resolved in v0.0.79