Cannot destructure property 'config' of 'undefined' error when sharing or exporting

[schlessera]

Describe the bug Export and sharing as SVG is broken for a diagram with the following error:

MermaidError: Cannot destructure property 'config' of 'undefined' as it is undefined. addVertex (file:///prod/mermaid-pre-render-server/node_modules/.pnpm/@mermaid-js+mermaid-cli@11.4.0_patch_hash=taxes6pgqytvd5wk2gq6oq35qe_puppeteer@23.8.0_typescript@5.6.3_/node_modules/@mermaid-js/mermaid-cli/dist/index.html:1046:1345)

To Reproduce Go to the following public SVG diagram to see the error: https://www.mermaidchart.com/raw/61fb7f6a-9a7c-4eed-bd0c-ac0875eeca81?theme=light&version=v0.1&format=svg

Here's the diagram source:

---
config:
  layout: elk
  theme: base
  look: classic
---
graph TB
    subgraph Server
        EXT["External Sources"]
        IMP["Importers"]
        subgraph Data["Data Layer"]
            DM["Core Data Model"]
            DB[(WordPress DB)]
        end
        subgraph Core["Core Layer"]
            SDK["PHP SDK"]
            REST["REST API"]
            SDK --> REST
            DM --> SDK
        end
        subgraph WP["WordPress Integration"]
            GB["Gutenberg Blocks"]
            PAT["Block Patterns"]
            THEME["Sanctioned Theme"]
            GB --> THEME
            PAT --> THEME
        end
    end
    subgraph Client
        subgraph Frontend["Frontend Layer"]
            UI["User Interface"]
            CMS["Content Management"]
        end
    end
    VIS@{ icon: "fa:user", label: "Visitor"}
    MAN@{ icon: "fa:user", label: "Manager"}

    IMP --> DM
    EXT --> DM
    DM --> DB
    REST <--> UI
    REST <--> CMS
    GB --> SDK
    GB --> REST
    GB --> UI
    PAT --> SDK
    THEME --> REST
    UI --> VIS
    CMS --> MAN
    classDef core fill:#f9f,stroke:#333,stroke-width:2px
    classDef data fill:#bbf,stroke:#333,stroke-width:2px
    classDef wp fill:#bfb,stroke:#333,stroke-width:2px
    classDef front fill:#fbb,stroke:#333,stroke-width:2px
    classDef phase2 stroke-dasharray: 5 5
    class DM,IMP,DB,EXT data
    class SDK,REST core
    class GB,PAT,THEME wp
    class UI,CMS,VIS,MAN front
    class IMP,EXT phase2

Expected behavior SVG representation of the diagram.

Additional context Renders fine in the editor.

[schlessera]

I have pinpointed it to the layout engine config:

---
config:
  layout: elk
---

When I remove the layout: elk line in the config, the diagram renders (albeit in a layout I don't want). Seems like the elk layout works in the editor but breaks when exporting/sharing.