DocumentLayoutException: 'Composed layout generates infinite document.' is thrown when number of invoice detail items is 4967 or over in 'example-invoice' repository about questpdf

[MarcinZiabek]

Hello :) There are two reasons possible behind the DocumentLayoutException.

1. Some elements in the document structure cannot be successfully rendered because of size constraints. This is sometimes very challenging to detect. In such cases, the results document will have infinite length. There is a special breaker that detects too long documents and throws an exception. Please take a look at the metadata settings and the DocumentLayoutExceptionThreshold parameter.
2. The second case is when you generate a lot of content and hit the threshold described above. I bet it is what happened in your case. Increasing the threshold will surely help :)

In one of the experimental branches, I am already working on the improvements regarding this exception. When it is thrown, you will get a full elements trace (similar to stack trace) describing all size constraints, rendering types, etc. Such trace will point you where specifically the problem happens. Super useful, yet still requires some work!

[preiius]

You're right, it's DocumentLayoutExceptionThreshold .

I'm surprised it's set so low, but I guess whatever you set it to, someone is going to complain eventually!

As to why exception is thrown intermittently when count is 4967, random comment field at the end sometimes push number of pages to 250.

[MarcinZiabek]

This is tricky to decide. I expect/suppose that most users will generate relatively short documents. When this exception happens, the library literally needs to generate so many pages, using processor and memory resources. Therefore, if I set this value really high (let's say 10000 pages), it will be just wasteful.

What about adding a more sophisticated exception message? That describes both cases and let the developer know how to deal with them? E.g. to increase the threshold?

[preiius]

Yes, I thought of that, but I didn't want to take up any more of your free time.