reinstate_credit_line from Defaulted

[Phantomcall]

feat(credit): reinstate_credit_line — Defaulted → Active / Suspended

Summary

Implements reinstate_credit_line as a public contract entry point, allowing an admin to transition a credit line out of the Defaulted state back to either Active or Suspended, per the documented state machine. Also resolves a set of pre-existing compilation and test errors that were blocking the build.

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What Changed

Core Feature — reinstate_credit_line

contracts/credit/src/lifecycle.rs

Updated the existing reinstate_credit_line function to accept a target_status: CreditStatus parameter instead of hardcoding Active. The function now:

• Validates the credit line exists (panics with "Credit line not found" otherwise)
• Validates the current status is Defaulted (panics with "credit line is not defaulted" otherwise)
• Validates target_status is either Active or Suspended (panics with "target_status must be Active or Suspended" for any other value)
• Persists the new status
• Emits a ("credit", "reinstate") CreditLineEvent with the new status

contracts/credit/src/lib.rs

Exposed reinstate_credit_line as a public #[contractimpl] function on the Credit struct, with full doc comments covering parameters, panics, events, and post-reinstatement invariants.

State Machine

Active ──────────────────────────────────────────► Closed
  │                                                   ▲
  ▼                                                   │
Suspended ──────────────────────────────────────────► │
  │                                                   │
  ▼                                                   │
Defaulted ──── reinstate_credit_line ──► Active ─────►│
                                     └─► Suspended ──►│

Invariants After Reinstatement

• utilized_amount is preserved unchanged (outstanding debt is not forgiven)
• credit_limit, interest_rate_bps, and risk_score are unchanged
• Draws are re-enabled when target is Active; remain disabled when target is Suspended
• Only admin can call this function

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Tests Added (contracts/credit/src/test.rs)

12 new explicit transition tests:

Test	What it covers
test_reinstate_to_active_enables_draws	Defaulted → Active; draw succeeds after
test_reinstate_to_suspended_status	Defaulted → Suspended; status is Suspended
test_reinstate_to_suspended_blocks_draws	Defaulted → Suspended; draw still panics
test_reinstate_preserves_utilized_amount	All fields unchanged after → Active
test_reinstate_to_suspended_preserves_utilized_amount	All fields unchanged after → Suspended
test_reinstate_invalid_target_status_closed_reverts	Closed as target panics
test_reinstate_invalid_target_status_defaulted_reverts	Defaulted as target panics
test_reinstate_to_active_emits_event_with_active_status	Event has correct status + borrower
test_reinstate_to_suspended_emits_event_with_suspended_status	Event has correct status + borrower
test_reinstate_to_active_then_suspend_again	Full round-trip: Defaulted → Active → Suspended
test_reinstate_to_suspended_then_admin_close	Defaulted → Suspended → Closed
test_reinstate_to_suspended_unauthorized	Non-admin call panics

All existing reinstate call sites updated to pass &CreditStatus::Active as the target.

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Pre-existing Errors Fixed

The codebase had 97 compilation errors and several failing tests before this PR. The following were resolved as part of this work:

Compilation Errors (lib.rs)

Error	Root Cause	Fix
ContractError undeclared	use types::{} was missing ContractError	Added to import
config::set_liquidity_token / set_liquidity_source	mod config was never declared in lib.rs	Inlined the two function bodies directly
query::get_credit_line	mod query was never declared in lib.rs	Inlined env.storage().persistent().get(&borrower)
risk::set_rate_change_limits / get_rate_change_limits	mod risk was never declared in lib.rs	Inlined both function bodies
CreditLineData missing fields	accrued_interest and last_accrual_ts added to types.rs but not to the struct literal in open_credit_line	Added both fields initialised to 0
Missing SPDX header	lib.rs first line was #![no_std]	Added // SPDX-License-Identifier: MIT as line 1

Test Errors (lib.rs test modules)

Test	Problem	Fix
All repay tests in mod test	setup() and approve() helpers called but not defined in that module	Added both helpers to mod test
Event tests in mod test	TryFromVal / TryIntoVal not in scope	Added to use statement
test_suspend_nonexistent_credit_line	Body opened a line with invalid rate (10001) instead of suspending a nonexistent borrower	Rewrote to call suspend_credit_line on an address with no line
suspend_defaulted_line_reverts	Body was testing draw/balance assertions, never called default_credit_line or suspend_credit_line	Rewrote to: default → suspend → expect panic
test_draw_credit_updates_utilized	Called update_risk_parameters with risk_score = 101 (exceeds max of 100)	Changed to 70
test_multiple_borrowers (smoke)	Called suspend_credit_line after default_credit_line — invalid transition that panics	Rewrote to open two borrowers and assert independent state
test_event_reinstate_credit_line (coverage gaps)	Called setup_contract_with_credit_line which is not in scope in that module	Switched to base_setup which is defined in the same module

Integration Test Error (tests/duplicate_open_policy.rs)

Error	Root Cause	Fix
Non-exhaustive match on CreditStatus	Restricted variant added to enum but not covered in match	Added CreditStatus::Restricted => {} arm

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Test Results

test result: ok. 66 passed; 0 failed  (lib)
test result: ok. 28 passed; 0 failed  (integration)
test result: ok. 3 passed;  0 failed  (spdx_header_bug_exploration)
test result: ok. 6 passed;  0 failed  (spdx_preservation)
test result: ok. 7 passed;  0 failed  (duplicate_open_policy)

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Security Notes

• reinstate_credit_line is admin-only. No borrower-initiated reinstatement path exists.
• Trust boundary: the admin is assumed to be a trusted off-chain system or multisig. No on-chain oracle or automated trigger is wired to this function.
• utilized_amount is intentionally preserved on reinstatement — the debt does not disappear. Reinstating to Active re-enables draws, so the admin should verify the borrower's repayment capacity before reinstating.
• Reinstating to Suspended is a safer intermediate step: it clears the Defaulted flag (e.g. for accounting) while keeping draws locked until a subsequent Active transition.
• Failure mode: if the admin key is compromised, an attacker could reinstate defaulted lines and allow draws. This is the same trust boundary as all other admin-only lifecycle functions.

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Closes #115

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