Error when querying subgraphs: "panic processing query: called `Option::unwrap()` on a `None` value"

The following query returns an error on most subgraphs:

Subgraphs that returns an error:
https://thegraph.com/hosted-service/subgraph/aave/protocol-v2
https://thegraph.com/hosted-service/subgraph/ensdomains/ens
https://thegraph.com/hosted-service/subgraph/uniswap/uniswap-v2
+++

Query:

{
  __schema{
    types{
      fields{
        name
      }
    }
  }
   _meta{
    deployment
  }
}

Error message

"message": "panic processing query: called `Option::unwrap()` on a `None` value"

Exception: The query works on this subgraph:
https://thegraph.com/hosted-service/subgraph/graphprotocol/compound-v2

If I split the query into two separate queries, they work for all tested subgraphs:

{
  __schema{
    types{
      fields{
        name
      }
    }
  }
}

{
   _meta{
    deployment
  }
}

首先，在受影响的子图上重现组合的 __schema 和 _meta 查询，然后将其与分别成功的查询以及正常工作的 Compound 子图进行比较。当组合查询在报告的子图上完成且没有出现 Option::unwrap() panic 时，即表示完成。