Fix multiple issues in SessionPool and PooledTableSession

[shuwenwei]

No description provided.

[Copilot]

Pull request overview

This PR aims to improve robustness of SessionPool / TableSessionPool behavior (especially around error/close paths) and adds supporting e2e coverage, along with regenerated/extended Thrift types in common.

Changes:

• Add closed-state handling to PooledTableSession operations and make connection-error cleanup idempotent.
• Fix SessionPool semaphore handling when session construction fails; add nil-checks around session.trans.
• Add an e2e test intended to exercise error scenarios in TableSessionPool, and extend generated Thrift structs in common/common.go.

Reviewed changes

Copilot reviewed 4 out of 5 changed files in this pull request and generated 6 comments.

File	Description
test/e2e/e2e_table_test.go	Adds a new e2e test for error/close behavior in TableSessionPool.
client/tablesessionpool.go	Adds ErrTableSessionClosed and hardens pooled session lifecycle on errors/close.
client/sessionpool.go	Adjusts semaphore release on construct failures and adds transport nil-checks.
common/common.go	Adds new Thrift-generated structs related to external services (plus minor regeneration diffs).

Comments suppressed due to low confidence (2)

client/sessionpool.go:175

• PutBack can panic when sending on spool.ch (e.g., if the pool is concurrently closed). In that case the deferred recover runs, but <-spool.sem is skipped because the function returns immediately after recover, leaking a semaphore token. Make semaphore release unconditional via a defer (and avoid doing it after the potentially panicking send).

	defer func() {
		if r := recover(); r != nil {
			session.Close()
		}
	}()
	if session.trans != nil && session.trans.IsOpen() {
		spool.ch <- session
	}
	<-spool.sem
}

client/sessionpool.go:190

• Similarly to PutBack, if session.Close() panics inside dropSession, the deferred recover prevents the panic from crashing but the code after the panic (including <-spool.sem) will not run, leaking a semaphore token. Release the semaphore in a defer so it happens even if session.Close() panics.

func (spool *SessionPool) dropSession(session Session) {
	defer func() {
		if e := recover(); e != nil {
			if session.trans != nil && session.trans.IsOpen() {
				session.Close()
			}
		}
	}()
	err := session.Close()
	if err != nil {
		log.Println("Failed to close session ", session)
	}
	<-spool.sem
}

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