[PR] fix(ai-prompt-*): handle nil err in JSON body parse path [apisix]

["shreemaan-abhishek (via GitHub)" <gi...@apache.org>]

shreemaan-abhishek opened a new pull request, #13314:
URL: https://github.com/apache/apisix/pull/13314

   ### Description
   
   Follow-up to #13096 (which corrected the wording of the JSON-parse error message in the AI prompt plugins). That patch left two nil-concatenation hazards behind that turn the affected plugins into 500s instead of returning the intended 4xx client error:
   
   1. `core.request.get_body()` can return `nil` with `err == nil` for **empty** request bodies. With:
   
      ```lua
      return nil, { message = "could not get body: " .. err }
      ```
   
      the concatenation crashes with `attempt to concatenate local 'err' (a nil value)`.
   
   2. `core.json.decode()` returning `nil` with `err == nil` is much rarer but still possible, and the same concatenation hazard applies.
   
   Affected files:
   
   - `apisix/core/request.lua` — `get_json_request_body_table()`. The `get_body()` branch already had an `(err or "request body is empty")` guard from a previous patch; this PR adds the matching guard on the `json.decode()` branch.
   - `apisix/plugins/ai-prompt-template.lua` — `get_request_body_table()`. Both branches need the guard.
   - `apisix/plugins/ai-prompt-decorator.lua` — `get_request_body_table()`. Both branches need the guard.
   
   Reproduction (before this PR):
   
   ```
   POST / HTTP/1.1
   Content-Type: application/json
   Content-Length: 0
   
   ```
   
   with `ai-prompt-template` enabled returns 500 instead of the configured "could not get body: request body is empty" message.
   
   #### Which issue(s) this PR fixes:
   
   Follow-up to #13096; no separate issue.
   
   ### Checklist
   
   - [x] I have explained the need for this PR and the problem it solves
   - [x] I have explained the changes or the new features added to this PR
   - [ ] I have added tests corresponding to this change — *the existing `t/admin/routes_request_body.t` exercises the nil-`err` empty-body path and now correctly produces the configured error message; happy to add a focused regression test in `t/plugin/ai-prompt-template.t` if reviewers want one.*
   - [x] I have updated the documentation to reflect this change — *no doc impact; behaviour is now the documented one.*
   - [x] I have verified that this change is backward compatible
   


-- 
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.

To unsubscribe, e-mail: notifications-unsubscribe@apisix.apache.org

For queries about this service, please contact Infrastructure at:
users@infra.apache.org

Re: [PR] fix(ai-prompt-*): handle nil err in JSON body parse path [apisix]

["shreemaan-abhishek (via GitHub)" <gi...@apache.org>]

shreemaan-abhishek merged PR #13314:
URL: https://github.com/apache/apisix/pull/13314


-- 
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.

To unsubscribe, e-mail: notifications-unsubscribe@apisix.apache.org

For queries about this service, please contact Infrastructure at:
users@infra.apache.org