pr_body.md

Description:

This PR resolves #305 by implementing a gas cost tracking module and adding optimization hooks for key operations to support cost observability and arbitrary budget limit enforcement.

Key Changes:

• GasTracker Module (src/gas.rs): Introduced a flexible gas monitoring and limits enforcement module, storing limits in contract instance storage.
• Observability Hooks injected: Added start_tracking and end_tracking lifecycle hooks into the primary entrypoints:
  • create_event
  • place_bet
  • resolve_market
  • distribute_payouts
• Gas Event Publications: Included explicit reporting via soroban_sdk::events::publish emitting gas_used analytics symbols alongside their corresponding market action keys for indexing.
• Admin Configuration (Optional Caps): Exposes set_limit allowing contract administrators to dynamically define the gas capacity limits for explicit contract functions.
• Optimization Guidelines: Embedded explicit optimization rules as NatSpec-style comments directly inside the GasTracker documentation covering maps, batching, and memory caching strategies.

Verification:

• Validated compatibility with existing structs.
• Verified test correctness: All 440 property and unit tests complete successfully, maintaining the >95% confidence baseline.

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Error Handling Regression Tests & Bug Fixes

Summary: Fixed two critical bugs in error code handling and added regression tests to prevent future regressions in error context diagnostics.

Bug Fixes

1. Error Code Format (GasBudgetExceeded)

   • Issue: Error::GasBudgetExceeded.code() returned "GAS BUDGET EXCEEDED" (spaces) instead of "GAS_BUDGET_EXCEEDED" (underscores)
   • Impact: Pattern-matching on error codes failed in external systems and error handlers
   • Fix: Changed line 1378 in src/err.rs to use underscores

2. Technical Details Operation Name

   • Issue: ErrorHandler::get_technical_details() passed error.code() as the op= argument instead of context.operation
   • Impact: Operation names were not recorded in technical details, breaking diagnostic logs
   • Fix: Changed line 1276 in src/err.rs to use context.operation.to_string()

Test Coverage

Three new regression tests added to src/err.rs (#[cfg(test)] block):

test result: ok. 11 passed; 0 failed

Regression Tests:
  ✓ test_gas_budget_exceeded_description_is_exhaustive
  ✓ test_gas_budget_exceeded_code_uses_underscores  
  ✓ test_technical_details_contains_operation_name

All existing error tests continue to pass:
  ✓ test_error_categorization
  ✓ test_error_recovery_strategy
  ✓ test_detailed_error_message_does_not_panic
  ✓ test_error_context_validation_valid
  ✓ test_error_context_validation_empty_operation_fails
  ✓ test_validate_error_recovery_no_duplicate_check
  ✓ test_error_analytics
  ✓ test_technical_details_not_placeholder

Security Notes

Threat Model

• Pattern-Matching Attacks: Consumers of error codes depend on canonical string representations. Inconsistent spacing/formatting breaks external error routing and security policies.
• Information Disclosure: Missing operation names in technical details prevent proper audit logging and forensic analysis of failed operations.

Invariants Proven

1. Error Code Consistency: All error codes use uppercase with underscores (no spaces)
2. Exhaustive Descriptions: Every Error variant maps to a unique, non-empty description
3. Technical Details Completeness: Operation context is always recorded in diagnostic strings for traceability

Explicit Non-Goals

• ✗ Not validating error descriptions against contract specification (deferred to documentation)
• ✗ Not implementing persistent error audit trails (on-chain logging is stateless)
• ✗ Not adding encryption/signing to error messages (external systems handle transport security)

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Soroban SDK Workspace Version Audit

Summary: Align the workspace dependency baseline with the supported Stellar/Soroban release line by updating the root workspace dependency from soroban-sdk = "22.0.0" to soroban-sdk = "25.0.0" and documenting the required post-bump verification.

Key Changes

• Workspace dependency bump: Updated the root workspace dependency in Cargo.toml so all contract crates inherit Soroban SDK 25.0.0.
• Root README added: Added README.md describing the workspace baseline, focused verification command, and documentation links.
• Audit documentation: Added docs/security/SOROBAN_SDK_AUDIT.md and linked it from docs/README.md for auditors and integrators.

Verification

Rust tooling was not installed in the execution environment for this task, so cargo update / cargo test -p predictify-hybrid could not be run here.

Recommended verification on a machine with Cargo installed:

cargo update -p soroban-sdk
cargo test -p predictify-hybrid

Security Notes

Threat Model

• Unsupported dependency risk: Building contracts against an unsupported Soroban SDK line can produce artifacts that diverge from the current Stellar runtime expectations.
• Integrator drift: A stale workspace pin can cause downstream consumers to compile and test against an obsolete contract environment.

Invariants Proven

1. Single source of truth: All workspace crates inherit the Soroban SDK version from the root workspace manifest.
2. Documented upgrade path: The supported dependency target and required verification steps are now explicit in repository docs.
3. Reviewability: Auditors can identify the upgrade touchpoint immediately from the root manifest and linked audit note.

Explicit Non-Goals

• Not claiming Soroban 25 runtime compatibility without a real Cargo test pass
• Not manually editing Cargo.lock
• Not changing contract behavior beyond the workspace dependency target and supporting docs