Syntax error when SPARQL Insert request is too large

When sending PATCH request with a really large SPARQL Insert body, NSS responds with http code 400 and the following response body:

Patch document syntax error: Line 1 of <https://pod.example/resource>: Bad syntax:
   Unknown syntax at start of statememt: '[object Object]'
   at: "[object Object]"

This response is very misleading, since it asserts that I did send an invalid syntax

Expected behaviour

NSS should either process the request successfully, or respond with 413 Request Entity Too Large.

Steps to reproduce

Send something like this to NSS:

PATCH https://pod.example/resource
content-type: application/sparql-update
authorization: DPoP <token>
dpop: <dpop>

INSERT DATA {
</> <> "".
</> <> "".
</> <> "".
</> <> "".
</> <> "".
... round about 10.000 more of this ...
}

Is this really practically relevant?

Yes, see https://github.com/codecentric/web-clip/issues/7

First we had an actual syntax error. After fixing it, same response on NSS but this time just too large.

Depending on the page, WebClip might do really large insert requests. If we got a 413 we could at least handle it properly

まず、application/sparql-update リクエストに対する NSS の PATCH 処理と、リクエストサイズのエラーパスを追跡し、次に提供された大きな INSERT の例を再現します。対応している場合はリクエストが処理され、対応していない場合は誤解を招く構文エラーではなく HTTP 413 Request Entity Too Large を返せば完了です。