Expose clear_pending_commit in UniFFI bindings

[dannym-arx]

This PR exposes the clear_pending_commit() method through the UniFFI bindings, allowing foreign language clients to roll back uncommitted pending MLS commits. This is a recovery mechanism for failed relay publishes that would otherwise permanently block group operations.

What changed:

• Added clear_pending_commit(mls_group_id: String) public method to the Mdk struct in the mdk-uniffi crate, which accepts a hex-encoded MLS group ID and rolls back to the pre-commit state
• Updated mdk-uniffi CHANGELOG.md to document the new method

API surface:

• New public method added to mdk-uniffi's Mdk type that mirrors the existing merge_pending_commit() flow but performs a rollback instead of merge
• The method parses the hex-encoded group ID and delegates to the underlying mdk-core implementation with error handling

[coderabbitai]

📝 Walkthrough

Walkthrough

The PR adds a new clear_pending_commit method to the MDK uniffi API that allows callers to roll back uncommitted pending MLS commits. This includes a CHANGELOG entry and the method implementation in the library, which parses a hex-encoded group ID and delegates to the internal MDK.

Changes

Cohort / File(s)	Summary
Documentation crates/mdk-uniffi/CHANGELOG.md	Added entry under Unreleased "Added" section documenting the new clear_pending_commit(group_id) method with reference to PR #196.
Implementation crates/mdk-uniffi/src/lib.rs	Implemented new public clear_pending_commit method that accepts a hex-encoded MLS group ID string, parses it to GroupId, and delegates to internal MDK to clear the pending commit, returning Result with MdkUniffiError on failure.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~8 minutes

Possibly related issues

• Expose clear_pending_commit from OpenMLS #194: Directly related as this PR exposes the same clear_pending_commit functionality through the uniffi API to allow clearing pending MLS commits.

Possibly related PRs

• feat: add clear_pending_commit for publish failure recovery #192: Directly related as the main PR adds the underlying clear_pending_commit implementation in mdk-core that this uniffi wrapper delegates to.

Suggested labels

mls-protocol

Suggested reviewers

• erskingardner

🚥 Pre-merge checks | ✅ 4

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title 'Expose clear_pending_commit in UniFFI bindings' clearly and concisely summarizes the main change in the pull request.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.
No Sensitive Identifier Leakage	✅ Passed	The clear_pending_commit method does not leak sensitive identifiers; it parses hex-encoded group IDs safely and only exposes error descriptions.

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✨ Finishing Touches

• 📝 Generate docstrings (stacked PR)
• 📝 Generate docstrings (commit on current branch)

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch expose-clear_pending_commit-to-bindings

---

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[github-actions]

❌ Coverage: 91.04% → 91.02% (-0.02%)

[github-actions]

❌ Coverage: 91.04% → 91.02% (-0.02%)

[erskingardner]

All good, unless you want to add a test, but given it's the thinnest wrapper possible, I'm fine with this.

[coderabbitai]

🧹 Nitpick comments (1)

crates/mdk-uniffi/src/lib.rs (1)

810-814: Consider adding a unit test for clear_pending_commit.

While the implementation is straightforward and follows the same pattern as merge_pending_commit, adding a test would verify the FFI binding works correctly end-to-end. A test could create a group, verify clear_pending_commit succeeds on a group with a pending commit, and returns an error for a non-existent group.

🤖 Prompt for AI Agents

Verify each finding against the current code and only fix it if needed.

In `@crates/mdk-uniffi/src/lib.rs` around lines 810 - 814, Add a unit test for
clear_pending_commit similar to the existing merge_pending_commit test:
instantiate the MdkUniffi object, create a test group (so there is a pending
commit), call clear_pending_commit(&self, mls_group_id: String) and assert it
returns Ok and that the group's pending commit is cleared; then call
clear_pending_commit with a non-existent group id and assert it returns an Err
(or the appropriate MdkUniffiError). Use parse_group_id/lock behavior indirectly
via the public API and mirror the structure/assertions from the
merge_pending_commit test to verify the FFI binding end-to-end.

ℹ️ Review info

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between 06a0636 and 8469240.

📒 Files selected for processing (2)

• crates/mdk-uniffi/CHANGELOG.md
• crates/mdk-uniffi/src/lib.rs

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Nitpick comments:
In `@crates/mdk-uniffi/src/lib.rs`:
- Around line 810-814: Add a unit test for clear_pending_commit similar to the
existing merge_pending_commit test: instantiate the MdkUniffi object, create a
test group (so there is a pending commit), call clear_pending_commit(&self,
mls_group_id: String) and assert it returns Ok and that the group's pending
commit is cleared; then call clear_pending_commit with a non-existent group id
and assert it returns an Err (or the appropriate MdkUniffiError). Use
parse_group_id/lock behavior indirectly via the public API and mirror the
structure/assertions from the merge_pending_commit test to verify the FFI
binding end-to-end.

[dannym-arx]

I don't think we need a test personally, the useful tests are in the PR introducing clear_pending_commit. Any test added here would just be silly imo