Default PURGE_VIEW_METADATA_ON_DROP to false so views can be dropped out of the box

[ayushtkn]

Fixes: #5293

Checklist

• 🛡️ Don't disclose security issues! (contact security@apache.org)
• 🔗 Clearly explained why the changes are needed, or linked related issues: Fixes #
• 🧪 Added/updated tests with good coverage, or manually tested (and explained how)
• 💡 Added comments for complex logic
• 🧾 Updated CHANGELOG.md (if needed)
• 📚 Updated documentation in site/content/in-dev/unreleased (if needed)

[Copilot]

Pull request overview

Warning

Copilot couldn't run its full agentic review because it didn't start before the timeout. Make sure your repository has a runner available, or add a copilot-code-review.yml file specifying one with the runs-on attribute. See the docs for more details.

Updates the default behavior of view drops by changing PURGE_VIEW_METADATA_ON_DROP to default to false, allowing views to be dropped under default configuration without requiring purge support.

Changes:

• Change PURGE_VIEW_METADATA_ON_DROP default from true to false and document dependency on DROP_WITH_PURGE_ENABLED.
• Add an integration test ensuring dropView succeeds when purge-related config is not explicitly set.
• Document the breaking/default behavior change in CHANGELOG.md.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 3 comments.

File	Description
site/content/in-dev/unreleased/configuration/config-sections/flags-polaris_features.md	Updates the documented default and adds dependency note, but introduces formatting inconsistencies.
polaris-core/src/main/java/org/apache/polaris/core/config/FeatureConfiguration.java	Changes the feature flag default and clarifies description text.
integration-tests/src/main/java/org/apache/polaris/service/it/test/PolarisRestCatalogIntegrationBase.java	Adds integration test coverage for dropping views with default purge behavior.
CHANGELOG.md	Announces the default change and provides upgrade guidance.

---

💡 Add a code-review agent skill or configure MCP servers for context-aware, tailored reviews. Learn more in the docs.

[vigneshio]

LGTM

[adutra]

This PR changes PURGE_VIEW_METADATA_ON_DROP's default from true to false. This "fixes" the reported inconsistency but creates a new problem: it silently couples two flags that were designed to be independent:

• DROP_WITH_PURGE_ENABLED is explicitly scoped to tables; its description reads "allows tables to be dropped with the purge parameter set to true."
• PURGE_VIEW_METADATA_ON_DROP was designed (I guess) as the authoritative, independent control for view purging.

After the PR, view metadata is only purged if the operator sets both DROP_WITH_PURGE_ENABLED=true and PURGE_VIEW_METADATA_ON_DROP=true.

So I'm wondering: isn't the right fix to decouple both flags?

@dimas-b WDYT?

[ayushtkn]

Thanx @adutra for the review!!!

This "fixes" the reported inconsistency but creates a new problem: it silently couples two flags that were designed to be independent:

I think they were always coupled, this PR doesn't adds that behaviour there is an existing test explicitily asserting that behaviour linked in the description of the reported issue here:
#5293 (comment)

To be precise this test actually asserts that they are dependent

polaris/integration-tests/src/main/java/org/apache/polaris/service/it/test/PolarisRestCatalogIntegrationBase.java

Lines 1902 to 1907 in ffa6977

	catalogProps.put(FeatureConfiguration.DROP_WITH_PURGE_ENABLED.catalogConfig(), "false");
	catalogProps.put(FeatureConfiguration.PURGE_VIEW_METADATA_ON_DROP.catalogConfig(), "true");
	managementApi.updateCatalog(catalog, catalogProps);
	assertThatThrownBy(() -> restCatalog.dropView(id)).isInstanceOf(ForbiddenException.class);

I had two solutions as mentioned in the description of the issue that either decouple them and let one deal with only tables or make the defaults sync. @dimas-b suggested to go with default change rather than tweaking the scope of the already existing config here
#5293 (comment)