Fix StreamCreate failure handling

[ljcjclljc]

What problem does this PR solve?

Issue Number: resolve #3356

Problem Summary:

StreamCreate(StreamId*, Controller&, const StreamOptions*) ignored the return
value of the batched overload. When the same Controller was reused to create a
request stream twice, the batched overload correctly returned -1, but the
single-stream wrapper still unconditionally accessed request_streams[0].
This could cause out-of-bounds access and crash the process.

What is changed and the side effects?

Changed:

• Check the return value of the batched StreamCreate in the single-stream wrapper
• Return the error code immediately when the inner call fails
• Add a regression test to verify that the second call on the same Controller
  returns -1 instead of crashing

Side effects:

• Performance effects:

  • None

• Breaking backward compatibility:

  • No API change
  • The behavior changes from crashing on invalid repeated use to returning -1

---

Check List:

• Please make sure your changes are compilable.
• When providing us with a new feature, it is best to add related tests.
• Please follow https://github.com/apache/brpc/blob/master/CODE_OF_CONDUCT.md .

Fixes#3356

[Copilot]

Pull request overview

Fixes a crash in StreamCreate(StreamId*, Controller&, ...) by correctly propagating failures from the batched StreamCreate(StreamIds&, ...) overload, preventing out-of-bounds access when a Controller is reused.

Changes:

• Check and return the inner (batched) StreamCreate return code in the single-stream wrapper before indexing request_streams[0].
• Add a regression unit test ensuring a second StreamCreate call on the same Controller returns -1 (no crash).

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
src/brpc/stream.cpp	Fixes the single-stream wrapper to respect the batched overload’s failure return and avoid indexing an empty vector.
test/brpc_stream_create_unittest.cpp	Adds a regression test covering repeated StreamCreate on the same Controller.

---

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