Add correlation ID fallback for async polling (Movable Ink)

[Linker44]

Ticket [ENG-XXXX]

Description Of Changes

Adds a fallback mechanism for correlation ID extraction in async polling. Some APIs (e.g. Movable Ink) return an empty response body after the initial DSR request, so extracting the correlation ID from the JSON response fails. This change allows the framework to resolve the correlation ID from param_value_map when the response body is empty — for example, using privacy_request_id which is always auto-populated.

This is fully backward-compatible: connectors that return correlation IDs in their response bodies continue to work via the primary extraction path.

Companion PR: ethyca/fidesplus — Movable Ink connector config, dataset, and tests.

Code Changes

• Added _extract_correlation_id() static method to AsyncPollingStrategy that tries the response body first, then falls back to param_value_map
• Refactored _handle_polling_initial_request and _handle_polling_initial_erasure_request to use the new shared method
• Added 5 unit tests covering: response body extraction, empty body fallback, non-JSON fallback, response-over-params precedence, and error case

Steps to Confirm

1. Run existing async polling tests to verify backward compatibility: pytest tests/ops/service/async_dsr/polling/test_async_polling_strategy.py -v
2. Verify new tests pass: pytest tests/ops/service/async_dsr/polling/test_async_polling_strategy.py -k test_extract_correlation_id -v

Pre-Merge Checklist

• Issue requirements met
• All CI pipelines succeeded
• CHANGELOG.md updated
  • Updates unreleased work already in Changelog, no new entry necessary
• UX feedback:
  • No UX review needed
• Followup issues:
  • No followup issues
• Database migrations:
  • No migrations
• Documentation:
  • No documentation updates required

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2 Skipped Deployments

Project	Deployment	Actions	Updated (UTC)
fides-plus-nightly	Ignored	Preview	May 5, 2026 2:43pm
fides-privacy-center	Ignored		May 5, 2026 2:43pm

[Vagoasdf]

I agree that this is something to be reviewed/checked. I dont think we should have a blanket pass on the ValueError, since a malformed JSON wouldn't get caught.

If what we are trying to pass on is an Empty ValueError we should aim for that specifcially with another check, and keep the ValueError exception to catch errors on the JSON responses, I.E:

  response_data = None
  if response.content:                                                                                                                                                                                          
      try:                                                                                                                                                                                                      
          response_data = response.json() ## Becomes null on empty response       
      except ValueError as exc:                                                                                                                                                                                 
          raise FidesopsException(f"Invalid JSON response: {exc}")                                
    
  if response_data and correlation_id_path:                                                                                                                                                                     
      correlation_id = pydash.get(response_data, correlation_id_path)
      if correlation_id:                                                                                                                                                                                        
          return str(correlation_id)  

[Linker44]

implemented

[codecov]

Codecov Report

❌ Patch coverage is 85.71429% with 3 lines in your changes missing coverage. Please review.
✅ Project coverage is 85.17%. Comparing base (f99bff4) to head (45eee2c).
⚠️ Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
...async_dsr/strategies/async_dsr_strategy_polling.py	85.71%	1 Missing and 2 partials ⚠️

❌ Your patch check has failed because the patch coverage (85.71%) is below the target coverage (100.00%). You can increase the patch coverage or adjust the target coverage.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #8034      +/-   ##
==========================================
+ Coverage   85.14%   85.17%   +0.02%     
==========================================
  Files         637      637              
  Lines       41936    41942       +6     
  Branches     4927     4930       +3     
==========================================
+ Hits        35707    35722      +15     
+ Misses       5121     5111      -10     
- Partials     1108     1109       +1     

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[Vagoasdf]

There Are a few changes required around the managment of errors, but besides that. the logic looks solid and the tests are complete. 👍🏽

[Vagoasdf]

I agree that this is something to be reviewed/checked. I dont think we should have a blanket pass on the ValueError, since a malformed JSON wouldn't get caught.

If what we are trying to pass on is an Empty ValueError we should aim for that specifcially with another check, and keep the ValueError exception to catch errors on the JSON responses, I.E:

  response_data = None
  if response.content:                                                                                                                                                                                          
      try:                                                                                                                                                                                                      
          response_data = response.json() ## Becomes null on empty response       
      except ValueError as exc:                                                                                                                                                                                 
          raise FidesopsException(f"Invalid JSON response: {exc}")                                
    
  if response_data and correlation_id_path:                                                                                                                                                                     
      correlation_id = pydash.get(response_data, correlation_id_path)
      if correlation_id:                                                                                                                                                                                        
          return str(correlation_id)