refactor: drop useless DashSpvClient.sync_to_tip

[xdustinface]

It's basically doing nothing except logging some things.

Based on:

• chore: drop unused integration tests #362

Summary by CodeRabbit

Release Notes

• Refactor

  • Removed synchronous sync_to_tip() and start_sync() public methods. Synchronization is now asynchronous via the run() method with cancellation token support.

• Documentation

  • Updated examples and API documentation to reflect the new asynchronous synchronization pattern.

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[coderabbitai]

📝 Walkthrough

Walkthrough

This PR removes the sync_to_tip and start_sync public APIs from both the FFI bindings and Rust client library, along with all related implementation code, tests, examples, and documentation. The synchronization pattern is being replaced with an asynchronous run loop approach.

Changes

Cohort / File(s)	Summary
FFI Documentation dash-spv-ffi/FFI_API.md, dash-spv-ffi/FFI_DOCS_README.md, dash-spv-ffi/README.md	Removed dash_spv_ffi_client_sync_to_tip from API documentation, function tables, and usage examples; reduced Synchronization function count from 7 to 6.
FFI Header Declaration dash-spv-ffi/include/dash_spv_ffi.h	Removed public FFI function declaration dash_spv_ffi_client_sync_to_tip (29 lines).
FFI Implementation dash-spv-ffi/src/client.rs	Removed CallbackInfo::Simple enum variant, dash_spv_ffi_client_sync_to_tip function, and associated callback handling; removed sync_to_tip invocation from dash_spv_ffi_client_test_sync.
FFI Documentation Generator dash-spv-ffi/scripts/generate_ffi_docs.py	Removed Markdown generation for the "Sync to chain tip" documentation block.
FFI Tests dash-spv-ffi/tests/c_tests/test_advanced.c, dash-spv-ffi/tests/integration/test_full_workflow.rs, dash-spv-ffi/tests/test_event_callbacks.rs, dash-spv-ffi/tests/unit/test_async_operations.rs, dash-spv-ffi/tests/unit/test_client_lifecycle.rs	Removed all invocations of dash_spv_ffi_client_sync_to_tip, callback setup blocks, and sync-related test assertions.
Rust Library API dash-spv/src/client/lifecycle.rs, dash-spv/src/client/sync_coordinator.rs	Removed public methods start_sync() and sync_to_tip(); eliminated pre-fetch synchronization pattern.
Rust Library Examples & Entry Point dash-spv/README.md, dash-spv/examples/filter_sync.rs, dash-spv/examples/simple_sync.rs, dash-spv/examples/spv_with_wallet.rs, dash-spv/src/main.rs	Removed sync_to_tip calls; replaced synchronous sync-then-stop pattern with asynchronous run(command_receiver, shutdown_token) pattern. Updated documentation examples to use command channels and cancellation tokens.
Rust Library Core dash-spv/src/lib.rs	Added CancellationToken import; updated crate documentation example to reflect new run-based workflow.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~25 minutes

Possibly related PRs

• feat: Introduce DashSpvClientInterface #214: Modifies DashSpvClient sync/monitor API—removes sync_to_tip entry point and introduces run with command-receiver/cancellation-token flow affecting the same core functions and files.

Suggested reviewers

• pauldelucia

Poem

🐰 The sync-to-tip hops away,

Replaced by run's asynchronous way,

Channels and tokens now guide the dance,

Simpler flows, a cleaner advance! ✨

🚥 Pre-merge checks | ✅ 3

✅ Passed checks (3 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title 'refactor: drop DashSpvClient.sync_to_tip' directly and clearly describes the main change: removal of the sync_to_tip method from DashSpvClient across the codebase.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

✨ Finishing touches

• 📝 Generate docstrings

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[coderabbitai]

Actionable comments posted: 0

Caution

Some comments are outside the diff and can’t be posted inline due to platform limitations.

⚠️ Outside diff range comments (2)

dash-spv/README.md (1)

52-69: Add the CancellationToken import so the example compiles.

The README snippet uses CancellationToken without importing it. All examples and implementations in the codebase import it from tokio_util::sync, which is a direct dependency.

🩹 Proposed doc fix

 use dash_spv::{ClientConfig, DashSpvClient};
+use tokio_util::sync::CancellationToken;

dash-spv-ffi/src/client.rs (1)

569-575: Pre-existing bug: early return leaks the client from the guard.

If the first sync_progress() call fails (lines 571-574), the function returns without restoring spv_client to the guard. This leaves inner holding None, causing subsequent operations to fail with "Client not initialized". Compare with lines 586-588 which correctly restore the client before returning.

Proposed fix

         let start_height = match spv_client.sync_progress().await {
             Ok(progress) => progress.header_height,
             Err(e) => {
                 tracing::error!("Failed to get initial height: {}", e);
+                let mut guard = client.inner.lock().unwrap();
+                *guard = Some(spv_client);
                 return Err(e);
             }
         };

🧹 Nitpick comments (1)

dash-spv-ffi/src/client.rs (1)

40-47: Consider simplifying CallbackInfo enum.

After removing the Simple variant, CallbackInfo now has only one variant (Detailed). While keeping it as an enum provides flexibility for future additions, you could simplify to a struct if no other variants are planned.

[ZocoLini]

FR i have never checked this method body before, definitely not the behavior i expected from a method with such name