Web Testpage Overlay has issues with DELETE operation

[heidi-holappa]

Bug description
We noticed, that DELETE operation on Web Testpage Overlay gives an error: "Error during processing: null". Under the hood it can be seen that the BaseController method ``processAndAddLastClientInvocation` gives a nullPointerException at line 515 (tag 7.6.0 release). To my understanding the reason is that our server reponds with 204 No Content (which is in line with the FHIR standard) and handling null response leads to the exception. Disclaimer: I may have misunderstood something along the way.

Note: Despite the Error the resource is successfully deleted.

To Reproduce
The fact that DELETE has issues can be reproduced in the official Hapi FHIR Web Testpage Overlay. I tested it with two resources and got different error from our case, but errors never the less. Based on this I propose that current state of the DELETE operation warrants taking a closer look at.

Case 1:

• I tested DELETE CRUD operation with DiagnosticReport resource 7001140 and got the following error:
• Error: HTTP 500 Server Error: HAPI-0389: Failed to call access method: org.springframework.orm.jpa.JpaSystemException: Unable to perform afterTransactionCompletion callback: HSEARCH800024: Unable to index documents for indexing after transaction completion: HSEARCH700124: Indexing failure: Could not load codec 'Lucene95'. Did you forget to add lucene-backward-codecs.jar?. The following entities may not have been updated correctly in the index: [ResourceTable#7001140].

Case 2:

• I tested DELETE CRUD operation with MedicationAdministration resource 76116 and got the following error:
• Error: HTTP 500 Server Error: HAPI-0389: Failed to call access method: org.springframework.orm.jpa.JpaSystemException: Unable to perform afterTransactionCompletion callback: HSEARCH800024: Unable to index documents for indexing after transaction completion: HSEARCH700124: Indexing failure: Could not load codec 'Lucene95'. Did you forget to add lucene-backward-codecs.jar?. The following entities may not have been updated correctly in the index: [ResourceTable#76116].

Note: despite the errors both resources were successfully deleted.

Steps to reproduce the behavior:

1. Go to https://hapi.fhir.org/home
2. Search for a resource and copy its ID
3. Select CRUD Operations for that resource type
4. Use DELETE operation and punch in the ID.
5. See error

Expected behavior
Some acknowledgement that the operation was carried out ok.

Environment (please complete the following information):

• HAPI FHIR Version: 7.6.0
• OS: Ubuntu 20.04.6
• Browser: Chrome