Gracefully handle null JSON responses from API

[sodle-splunk]

Changes

For some DELETE requests, notably when deleting an Alert, the API returns a JSON response containing only null. This is not seen as an empty response, because the content length is greater than zero.

When calling WorkspaceClient.alerts.delete(alertId), this results in the alert being deleted as expected. However, a TypeError is raised when trying to unpack the response at databricks/sdk/core.py:170.

To fix this, we will null-check the decoded JSON before attempting to unpack it. If it is None, we will simply return the response dict like we do for empty responses.

Tests

• make test run locally
• make fmt applied
  • This seems to have modified far more lines than expected.
  • Actual code changes are here
  • New test is here
• relevant integration tests applied
  • Added a test which shows the null response received when calling DELETE /api/2.0/preview/sql/alerts/alertid. This test fails before applying my fix, and passes with the fix in place.

[mgyucht]

I believe @tanmay-db was working on a fix for this case: #579.

[tanmay-db]

Hi @sodle-splunk, thanks for the PR. The formatting changes might be due to different versions of yapf being used, I ran make fmt on main branch and there were no diffs.

The test looks good and I tried to revert the make fmt commit so we could merge this PR but couldn't since I don't have the permission to push to your fork:

To github.com:sodle-splunk/databricks-sdk-py.git
 ! [remote rejected]   head -> sodle-splunk/main (permission denied)
error: failed to push some refs to 'github.com:sodle-splunk/databricks-sdk-py.git'

I have cherry picked the commits and added them to the PR: #579

[sodle-splunk]

Ah, I could have sworn I'd allowed maintainer commits on this PR. Oh well.

Thanks for cherry-picking. I'll close this one.