fix: recreate policy when removing WITH CHECK clause (#551)

[tianzhou]

Summary

• When a policy's WITH CHECK clause is removed, needsRecreate now returns true, triggering DROP + CREATE instead of ALTER POLICY
• Previously emitted invalid SQL WITH CHECK ; because ALTER POLICY cannot clear an existing WITH CHECK expression
• Adds regression test issue_551_remove_with_check verifying DROP + CREATE output

Closes #551

Test plan

• Diff test for the exact repro scenario passes
• Integration test applies successfully against real Postgres
• Full diff test suite passes
• Full integration test suite (running)

🤖 Generated with Claude Code

[greptile-apps]

Greptile Summary

This PR changes removal of a policy WITH CHECK clause from an invalid ALTER POLICY operation to transactional DROP-and-CREATE recreation.

• Adds the recreation condition in policy diffing.
• Adds a regression fixture covering the generated plan and SQL.
• The recreation path does not preserve an existing policy comment.

Confidence Score: 4/5

The policy recreation behavior should preserve existing policy comments before this PR is merged.

Removing WITH CHECK now drops and recreates the policy, but the recreation generator restores only structural clauses, so any existing COMMENT ON POLICY metadata is silently deleted.

Files Needing Attention: internal/diff/policy.go and the policy recreation branch in internal/diff/table.go

Important Files Changed

Filename	Overview
internal/diff/policy.go	Correctly detects that removing WITH CHECK requires recreation, but the selected recreation path drops unrelated policy comments.
testdata/diff/create_policy/issue_551_remove_with_check/old.sql	Defines the source policy with WITH CHECK but does not exercise preservation of attached policy metadata.
testdata/diff/create_policy/issue_551_remove_with_check/new.sql	Defines the intended policy state without WITH CHECK.
testdata/diff/create_policy/issue_551_remove_with_check/diff.sql	Correctly captures the expected DROP-and-CREATE SQL for the basic regression scenario.

_{Reviews (1): Last reviewed commit: "fix: recreate policy when removing WITH ..." | Re-trigger Greptile}

[Copilot]

Pull request overview

Fixes invalid SQL generation when removing an explicit RLS policy WITH CHECK clause by forcing policy recreation (DROP + CREATE) instead of attempting ALTER POLICY, and adds a regression diff test case for the reported scenario (#551).

Changes:

• Update needsRecreate to return true when a policy’s WITH CHECK clause is removed, avoiding invalid WITH CHECK ; output.
• Add a new diff regression fixture issue_551_remove_with_check validating DROP + CREATE plan output.

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 1 comment.

File	Description
internal/diff/policy.go	Changes policy recreation decision logic to handle WITH CHECK removal correctly.
testdata/diff/create_policy/issue_551_remove_with_check/*	Adds regression fixture asserting DROP + CREATE behavior in plan/diff outputs.

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[Copilot]

Pull request overview

Copilot reviewed 8 out of 8 changed files in this pull request and generated no new comments.