fix: guard NPE in NetworkUtil and concurrent read in IndexService

[btlqql]

Motivation

Three edge-case bugs found by code review (verified against the current develop branch):

1. NetworkUtil.socketAddress2String NPE (common/src/main/java/org/apache/rocketmq/common/utils/NetworkUtil.java)
   InetSocketAddress.getAddress() returns null when the hostname could not be resolved, so getAddress().getHostAddress() threw NullPointerException. This util is used across broker/namesrv/tools. Fall back to getHostString() when the address is null.

2. NetworkUtil.string2SocketAddress StringIndexOutOfBoundsException
   An address without : makes lastIndexOf(":") return -1, and substring(0, -1) throws StringIndexOutOfBoundsException. Throw a clear IllegalArgumentException instead.

3. IndexService.getTotalSize concurrent read (store/src/main/java/org/apache/rocketmq/store/index/IndexService.java)
   indexFileList is a plain ArrayList guarded by readWriteLock in every other accessor, but getTotalSize read it without the lock. A concurrent destroy()/deleteExpiredFile() could clear the list between the isEmpty() check and get(0), causing IndexOutOfBoundsException. Acquire the read lock.

Verification

mvn -pl broker -am compile passes on the build server.

Diff

2 files changed, +15 / -5.

[RockteMQ-AI]

Review by github-manager-bot

Summary

Guards against NPE in NetworkUtil.socketAddress2String when hostname is unresolved, adds input validation in string2SocketAddress, and fixes a race condition in IndexService.getTotalSize() by acquiring the read lock.

Findings

• [Info] NetworkUtil.java:195 — The new IllegalArgumentException for missing ':' is a good defensive check. Consider including the original address string in the error message (already done — 👍).
• [Info] NetworkUtil.java:207 — The null-guard on getAddress() with fallback to getHostString() correctly handles unresolved hostnames. This prevents NPE in broker/namesrv paths that use this utility.
• [Info] IndexService.java:95-103 — Wrapping getTotalSize() in the read lock correctly prevents the race between isEmpty() check and get(0) call. The existing readWriteLock is the right choice here.

Assessment

Clean, well-scoped bug fix. All three changes are correct and minimal. No backward compatibility concerns.

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Automated review by github-manager-bot