Send an empty JSON body for parameterless POST/PUT/PATCH requests

[tejaskochar-db]

Summary

Send an empty JSON object as the body for POST/PUT/PATCH requests that declare Content-Type: application/json but have no body to serialize, so the request is well-formed on the wire instead of being sent with no body at all.

Why

API methods for resource actions that take no parameters — for example WorkspaceClient.knowledge_assistants.sync_knowledge_sources(...), which issues POST .../knowledge-sources:sync — set Content-Type: application/json but pass no body to _BaseClient.do.

body defaults to None, and _perform calls requests with json=None. requests treats json=None as no body: the request goes out with Content-Length: 0 while still advertising Content-Type: application/json. Some Databricks API gateways require a JSON body (even an empty {}) for these endpoints and reject the bodyless request with 400 Bad Request.

The same operation succeeds when a body is supplied — calling w.api_client.do("POST", ".../knowledge-sources:sync", body={}) directly works. The proof is in how requests prepares the body:

call	wire body	Content-Length
json=None	None	0
json={}	b"{}"	2

This affects every generated method that declares a JSON content type but has no request fields (resource actions such as :sync, start, stop, cancel, undelete, …) — 20 such methods in the SDK today, and any added later.

What changed

Interface changes

None.

Behavioral changes

_BaseClient.do now defaults body to {} when all of the following hold: the method is POST/PUT/PATCH, Content-Type is application/json, and no body, data, or files is supplied. These requests previously went out with no body; they now carry {}.

GET/DELETE/HEAD, requests that already carry a body, and requests that do not declare application/json (e.g. streamed application/octet-stream uploads, or actions that intentionally send no body) are unchanged.

This mirrors the Go SDK, which marshals an empty request struct to {} and so has always sent a body for these endpoints.

Internal changes

None.

How is this tested?

Unit tests in tests/test_base_client.py cover the positive case parametrized over POST/PUT/PATCH (now sends {}) and the boundaries that must stay unchanged: a POST without a JSON content type sends no body; a GET is never given a body; an explicit files={} is left alone (no body injected); and an explicitly supplied falsy body such as [] is sent verbatim. Each test was confirmed to fail when the corresponding production logic is broken. Full test_base_client.py suite passes.

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This pull request and its description were written by Isaac.

[github-actions]

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Trigger:
go/deco-tests-run/sdk-py

Inputs:

• PR number: 1481
• Commit SHA: 2becbe80fea3e05a98bf6e61281949e602944d20

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[tejaskochar-db]

Closing this manual draft. This change will be delivered through the regular automated SDK update instead.