fix: update process_schedule_delegator_unstake

[1xstj]

Summary of changes
Changes introduced in this pull request:

• Fixes [BUG] process_schedule_delegator_unstake incorrectly includes nomination unstake requests in deposited asset validation #1048

[claude]

Claude finished @1xstj's task —— View job

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Code Review Complete ✅

I've analyzed the changes in this PR and they look good. Here's my comprehensive review:

Todo List:

• Read repository guidelines (CLAUDE.md)
• Analyze the code changes in delegate.rs
• Review the new test cases in delegate.rs
• Check for potential bugs and security issues
• Evaluate performance implications
• Assess documentation needs
• Provide comprehensive review feedback

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Summary of Changes

This PR fixes a bug in process_schedule_delegator_unstake where pending nomination unstake requests were incorrectly included in the calculation of available delegation balance.

Change made: Added && !r.is_nomination filter on line 242 in pallets/multi-asset-delegation/src/functions/delegate.rs

✅ Code Quality & Best Practices

• Logic Fix: The change correctly filters out nomination unstake requests when calculating available delegation balance
• Consistency: The fix aligns with similar patterns used elsewhere in the codebase (e.g., lines 235, 645, 946)
• Minimal Impact: Single-line change with clear intent and no side effects
• Code Style: Follows existing formatting and naming conventions

✅ Bug Analysis

The original bug occurred because:

1. Regular delegations and nomination delegations both use the same asset type (Asset::Custom(0))
2. The filter was matching ALL unstake requests for that operator/asset combination
3. This caused nomination unstake amounts to reduce available delegation balance incorrectly

Impact: This could prevent valid delegation unstaking when nomination unstakes were pending, potentially locking funds unnecessarily.

✅ Security Implications

• No Security Issues: The fix reduces restrictions rather than bypassing them
• Separation of Concerns: Properly isolates regular delegation logic from nomination logic
• No Economic Attacks: Cannot be exploited to drain funds or bypass limits
• Substrate Best Practices: Maintains proper error handling and validation

✅ Performance Considerations

• Minimal Impact: Adds one boolean check per iteration - negligible overhead
• O(n) Complexity: Still linear time complexity through unstake requests (unchanged)
• No Additional Storage: No new storage reads/writes introduced

✅ Test Coverage

The new test delegation_unstake_bug_with_nomination_pending is excellent:

• Reproduces the Issue: Sets up both delegation and nomination with pending unstake
• Verifies Fix: Confirms delegation unstaking works despite pending nomination unstake
• Comprehensive Setup: Tests the exact scenario that was failing
• Clear Assertions: Validates both requests exist and are properly separated

✅ Documentation

Current documentation is sufficient:

• Function comments already explain the validation logic
• The fix is self-explanatory and doesn't change the public interface
• Test case serves as additional documentation of the behavior

🔍 Inline Comments

Line 242 (pallets/multi-asset-delegation/src/functions/delegate.rs):

.filter(|r| r.operator == operator && r.asset == asset && !r.is_nomination)

✅ Perfect fix - The added && !r.is_nomination filter correctly excludes nomination unstake requests from delegation balance calculations.

Lines 941-1036 (pallets/multi-asset-delegation/src/tests/delegate.rs):
✅ Excellent test coverage - The new test case thoroughly validates the fix by:

• Creating both regular delegations and nominations
• Scheduling unstake for nominations first
• Verifying regular delegation unstake still works correctly

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Final Assessment: APPROVED ✅

This is a well-executed bug fix that:

• ✅ Addresses a legitimate issue with clear impact
• ✅ Uses minimal, targeted changes
• ✅ Includes comprehensive test coverage
• ✅ Maintains security and performance characteristics
• ✅ Follows best practices for Substrate development

Recommendation: This PR is ready to merge.

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