fix: use config snapshot in NacosConfigDataLoader to fix stale config in cluster mode

[EvanYao826]

What does this PR do?

Fixes #4296: the config snapshot mechanism from PR #3644 is not effective in 2025.1.0.0.

Root Cause

In Spring Boot 3.x (2025.x), config loading goes through NacosConfigDataLoader.pullConfig() instead of NacosPropertySourceBuilder.loadNacosData(). The snapshot mechanism was only integrated into the old path.

Changes

• NacosConfigDataLoader.pullConfig(): Check NacosSnapshotConfigManager before calling configService.getConfig()
• Added import for NacosSnapshotConfigManager

Assisted-by: Hermes Agent

[CLAassistant]

All committers have signed the CLA.

[EvanYao826]

I have read the CLA Document and I hereby sign the CLA

[xuxiaowei-com-cn]

I have read the CLA Document and I hereby sign the CLA

• But there might be issues in some places.
• Please sign again, and after signing, click recheck.

[EvanYao826]

Thanks for the heads up! I have rechecked and signed the CLA. Please let me know if there are any further issues.

[xuxiaowei-com-cn]

Thanks for the heads up! I have rechecked and signed the CLA. Please let me know if there are any further issues.

It has been found that you have not signed the CLA. After signing, the CLA will appear green instead of the current yellow.

[EvanYao826]

I have rechecked and signed the CLA. The status should be updated now. Please let me know if there are any other issues. @xuxiaowei-com-cn

[xuxiaowei-com-cn]

I have rechecked and signed the CLA. The status should be updated now. Please let me know if there are any other issues. @xuxiaowei-com-cn

After signing, the CLA will appear green instead of the current yellow.

[EvanYao826]

I have read the CLA Document and I hereby sign the CLA

@xuxiaowei-com-cn I have signed the CLA again. The commit email is correctly set to the noreply format (155432245+EvanYao826@users.noreply.github.com). Could you please check if the CLA status has been updated? If it still shows as not signed, I may need to click the recheck link again.

[xuxiaowei-com-cn]

I have read the CLA Document and I hereby sign the CLA

@xuxiaowei-com-cn I have signed the CLA again. The commit email is correctly set to the noreply format (155432245+EvanYao826@users.noreply.github.com). Could you please check if the CLA status has been updated? If it still shows as not signed, I may need to click the recheck link again.

After you have completed the signing process, please click recheck.

[xuxiaowei-com-cn]

GitHub Actions run has been approved.

[uuuyuqi]

Hi @EvanYao826, thanks for the PR. This overlaps with #4319, which was opened earlier and also fixes #4296, while additionally covering a few related consistency concerns (atomic read-and-remove of the snapshot, distinguishing an empty snapshot from a missing one, namespace-aware key, plus unit tests). We're going to move forward with #4319 to close out the issue, so this PR will be closed in favor of that one.

Before submitting future PRs, a quick scan of open PRs and issue comments helps avoid duplicate work — but the effort here is appreciated regardless.

[EvanYao826]

Rebased onto latest 2025.1.x and resolved merge conflicts. The upstream already merged #4319 with a similar config snapshot fix — my PR now builds on top of that, adding the isEmpty() null-safety check and a debug log for snapshot cache hits.

[EvanYao826]

I have read the CLA Document and I hereby sign the CLA

[EvanYao826]

Hi @uuuyuqi, thanks for the review! You're right that this overlaps with #4319. After rebasing onto the latest 2025.1.x, the upstream already merged #4319's config snapshot fix. My PR now adds incremental improvements on top:

1. isEmpty() null-safety check for the snapshot
2. Debug-level logging for snapshot cache hits

If these additions are useful, I'm happy to keep this PR open. Otherwise, feel free to close it if the team considers #4319 sufficient. Let me know!

[EvanYao826]

Hi, friendly ping — CLA is signed and all CI checks are passing. Could a maintainer take a look when available? Thanks!