fix(pd): pd raft-follower failed to get leader address due to npe

[JisoLya]

Purpose of the PR

• close #xxx

Main Changes

Verifying these changes

• Trivial rework / code cleanup without any test coverage. (No Need)
• Already covered by existing tests, such as (please modify tests here).
• Need tests and can be verified as follows:
  • xxx

Does this PR potentially affect the following parts?

• Dependencies (add/update license info & regenerate_known_dependencies.sh)
• Modify configurations
• The public API
• Other affects (typed here)
• Nope

Documentation Status

• Doc - TODO
• Doc - Done
• Doc - No Need

[imbajin]

Any context for it? And we should add some basic tests to ensure the logic right

[JisoLya]

The current implementation throws a NullPointerException (NPE) when performing cluster tests on a 3-node PD setup (see image).
Follower side:

Leader side (which has no any dbCompaction log):

The issue is reproducible with this test code:

@Test
    public void TestSimplePd() throws PDException {
		// 8686: leader, 8688 and 8687 are followers
        String addr = "127.0.0.1:8687";
        PDConfig pdConfig = PDConfig.of(addr);
        PDClient client = PDClient.create(pdConfig);
        client.dbCompaction();
    }

Send dbCompaction to followers after changes:
Follower side log:

Leader side log which is expected:

[Copilot]

Pull request overview

This PR fixes a NullPointerException (NPE) in the PD raft-follower component that occurred when attempting to get the leader address. The root cause was passing a null InvokeContext to JRaft's invokeAsync() method, which expects a non-null context object.

Key Change:

• Initialize InvokeContext with a new instance instead of using null in the internalCallAsyncWithRpc method

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.