issue-478.md

Implementation Plan: Validate Milestone.title Length Bound in create_vault

Objective

Introduce a hard limit on Milestone.title length in contracts/accountability_vault to prevent unbounded storage growth and excessive ledger fees caused by oversized string inputs.

This ensures predictable storage costs and improves contract safety and accountability.

Scope

Contract Changes (lib.rs)

• Introduce a constant:

  pub const MAX_TITLE_LEN: usize = 128;

• Validate Milestone.title inside create_vault before vault creation logic executes.

• Enforce byte-length validation (not character count) using String::len() semantics as defined by soroban_sdk::String.

• Reject any title where:

  • title.len() > MAX_TITLE_LEN

Error Handling

• Add a new error variant to the contract error enum:

  • TitleTooLong

• Alternatively (if error catalog constraints apply), evaluate reuse of InvalidAmount only if semantically acceptable; prefer explicit error for clarity.

• Ensure error is returned early and consistently before any storage writes occur.

Tests

File: contracts/accountability_vault/src/test.rs

Add boundary and regression tests:

• Valid case:

  • Title length exactly MAX_TITLE_LEN should succeed.

• Invalid case:

  • Title length MAX_TITLE_LEN + 1 should return TitleTooLong.

• Edge cases:

  • Empty title (if allowed by existing logic).
  • Multi-byte UTF-8 characters to confirm byte-length enforcement.

• Ensure no partial state is written on rejection.

Coverage Target

• ≥95% test coverage for modified contract paths.

Documentation

Update contracts/README.md

Include:

• Description of MAX_TITLE_LEN
• Rationale: storage cost control and ledger fee protection
• Behavior on validation failure
• Error returned (TitleTooLong)
• Example valid vs invalid input

Security Considerations

• Prevents unbounded ledger bloat via oversized metadata fields.
• Ensures predictable storage fees per vault creation.
• Eliminates potential DoS vectors through large string submissions.

Implementation Steps

1. Fork repository and create branch:

   git checkout -b bug/milestone-title-length-bound

2. Implement contract changes:

   • Add MAX_TITLE_LEN
   • Add validation in create_vault
   • Add error variant

3. Add tests in test.rs

4. Update README.md

5. Run full test suite:

   cargo test

6. Verify:

   • Boundary conditions pass
   • Over-limit titles fail correctly
   • No regression in vault creation logic

Commit Message

fix: bound milestone title length in create_vault

Expected Outcome

Vault creation enforces strict title size limits, preventing excessive storage usage and ensuring predictable on-chain costs while maintaining backward-compatible behavior for valid inputs.