[BugFix] Fix NPE in Iceberg metadata table query due to missing Configuration propagation

[jiuuon]

Why I'm doing:

When querying Iceberg metadata tables (history, snapshots, refs, etc.),
NPE occurs with message: "Cannot invoke Configuration.size() because conf is null".

This happens because:

1. IcebergCachingFileIO.getWrappedIO() returns ResolvingFileIO without Configuration set
2. When SerializableTable serializes the FileIO, it calls serializeConfWith()
3. SerializableConfSupplier constructor calls conf.size() on null Configuration

What I'm doing:

Fix getWrappedIO() to propagate Configuration to wrappedIO before returning.

• If conf is set via setConf(), use it
• If conf is null (e.g., REST catalog), use default new Configuration()

What type of PR is this:

• BugFix
• Feature
• Enhancement
• Refactor
• UT
• Doc
• Tool

Does this PR entail a change in behavior?

• Yes, this PR will result in a change in behavior.
• No, this PR will not result in a change in behavior.

If yes, please specify the type of change:

• Interface/UI changes: syntax, type conversion, expression evaluation, display information
• Parameter changes: default values, similar parameters but with different default values
• Policy changes: use new policy to replace old one, functionality automatically enabled
• Feature removed
• Miscellaneous: upgrade & downgrade compatibility, etc.

Checklist:

• I have added test cases for my bug fix or my new feature
• This pr needs user documentation (for new or modified features or behaviors)
  • I have added documentation for my new feature or new function
• This is a backport pr

Bugfix cherry-pick branch check:

• I have checked the version labels which the pr will be auto-backported to the target branch
  • 4.0
  • 3.5
  • 3.4
  • 3.3

---

Note

Bugfix: propagate Hadoop Configuration to wrapped FileIO

• Update IcebergCachingFileIO.getWrappedIO() to set wrappedIO's conf using existing conf or a default new Configuration() to avoid NPE during serializeConfWith
• Add unit tests validating configuration propagation with and without prior setConf() in IcebergCachingFileIOTest

^{Written by Cursor Bugbot for commit 423804d. This will update automatically on new commits. Configure here.}

[alvin-celerdata]

@cursor review

[cursor]

✅ Bugbot reviewed your changes and found no bugs!

[jiuuon]

Hi @dirtysalt @Youngwb

Could you please review this PR when you have a chance?

All CI checks have passed with 100% coverage on the changed lines.

Thanks!

[alvin-celerdata]

@mergify rebase

[mergify]

rebase

✅ Branch has been successfully rebased

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[github-actions]

[Java-Extensions Incremental Coverage Report]

✅ pass : 0 / 0 (0%)

[github-actions]

[FE Incremental Coverage Report]

✅ pass : 2 / 2 (100.00%)

file detail

	path	covered_line	new_line	coverage	not_covered_line_detail
🔵	com/starrocks/connector/iceberg/io/IcebergCachingFileIO.java	2	2	100.00%	[]

[github-actions]

[BE Incremental Coverage Report]

✅ pass : 0 / 0 (0%)