[SPARK-56413][UDF][BUILD][FOLLOWUP] Fix parent POM version in udf-worker-grpc module on branch-4.x

[cloud-fan]

What changes were proposed in this pull request?

When the udf-worker-grpc module was backported to branch-4.x in SPARK-56413/SPARK-56661 (commit 7a70689), its parent POM version in udf/worker/grpc/pom.xml was left at 5.0.0-SNAPSHOT (the master version) instead of 4.2.0-SNAPSHOT. This one-line change corrects it.

Why are the changes needed?

branch-4.x is at 4.2.0-SNAPSHOT, but udf/worker/grpc/pom.xml referenced parent spark-parent_2.13:5.0.0-SNAPSHOT, which cannot be resolved. Since the module is registered in the root POM <modules>, POM model building fails for every job, breaking the entire branch-4.x build:

[FATAL] Non-resolvable parent POM for org.apache.spark:spark-udf-worker-grpc_2.13:5.0.0-SNAPSHOT:
Could not find artifact org.apache.spark:spark-parent_2.13:pom:5.0.0-SNAPSHOT in central
... and 'parent.relativePath' points at wrong local POM @ line 24, column 11

The sibling modules udf/worker/core and udf/worker/proto already correctly use 4.2.0-SNAPSHOT.

Does this PR introduce any user-facing change?

No. Build-only fix on the unreleased branch-4.x.

How was this patch tested?

Existing CI. This unblocks all branch-4.x builds, which currently fail at the POM model building step before any compilation/tests run.

Was this patch authored or co-authored using generative AI tooling?

Generated-by: Claude Code (Opus 4.8)

This pull request and its description were written by Isaac.

[gaogaotiantian]

So we need to upgrade this to 4.3 after we branch 4.3? Or this should be 4.x and we change the cut branch to 4.3?

[cloud-fan]

This follows the same convention as every other POM - they all hardcode the version, and the sibling udf/worker/core and udf/worker/proto modules are already at 4.2.0-SNAPSHOT. When 4.3 is cut, the standard version-bump tooling rewrites all POMs together, so this gets updated automatically along with everything else. The issue here was just that the backport left this one file at the master version (5.0.0-SNAPSHOT) instead of matching the rest of the branch.

[cloud-fan]

also cc @haiyangsun-db @HyukjinKwon

[zhengruifeng]

should be 4.3.0 in branch-4.x?

[haiyangsun-db]

thanks for fixing, I think @zhengruifeng is right that this was newly introduced recently in spark 4.x (after 4.2 cut).

[cloud-fan]

The parent version has to match the root pom.xml, and branch-4.x is currently on 4.2.0-SNAPSHOT (not 4.3.0 yet), so 4.2.0-SNAPSHOT is the correct value here. This was the actual bug — the module had 5.0.0-SNAPSHOT (master's version) leaking onto the branch.

That said, you have a point that the branch version looks stale — we should likely bump branch-4.x to 4.3.0-SNAPSHOT in a separate change. But that's a branch-wide version bump (root POM + all modules), so it's out of scope for this fix.

[dongjoon-hyun]

+1, LGTM.

[cloud-fan]

thanks for review, merging to 4.x!