Suggested follow-up to #1203: extract helper + add IE090 tests

[MoonBoi9001]

Motivation

While reviewing #1203, two things stood out: the new over-allocation guard is duplicated byte-for-byte across the resolver path (reallocateHorizonAllocation) and the action-queue path (AllocationManager.populateReallocateTransaction), and the new IE090 throw has no test coverage. Without a shared helper, any future tweak to the guard — error message, additional diagnostic reads, metrics — has to happen twice and will eventually drift. Without tests, the guard could silently regress and we'd only find out when an over-allocated indexer hit the path in production.

This branch is offered as a suggestion stacked on top of #1203, not a replacement. Take, modify, or discard.

Summary

Two commits, each independent:

• refactor(allocations): extract over-allocation guard into shared helper — moves the duplicated 30-line block into assertNotOverAllocated in a new over-allocation.ts module. Both call sites in fix: gracefully handle overallocation when reallocating #1203 now invoke the helper. Side improvements while extracting:

  • Parallelises the two independent reads (allocationProvisionTracker and getDelegationRatio) — saves one round-trip on the error path.
  • Clamps the over-allocated delta to 0n to defend against a negative bigint formatting into the error message if the three reads race.
  • Reworks the IE090 message to point operators at graph indexer allocations close (which already handles over-allocation gracefully and still collects rewards) instead of the ambiguous "manually unallocate that amount."

• test(allocations): cover IE090 over-allocation guard for reallocate — four pure-unit tests against assertNotOverAllocated:

  1. happy path returns silently and skips the diagnostic reads
  2. over-allocated path throws IndexerError with code === IE090 and the GRT delta in the cause string
  3. verifier address (SubgraphService.target) and delegation ratio are forwarded correctly to HorizonStaking.getTokensAvailable
  4. negative delta from racing reads is clamped — message says 0.0 GRT, no minus sign

Verified

• yarn compile clean against locked @graphprotocol/toolshed@1.1.1
• yarn lint clean
• yarn test src/indexer-management/__tests__/over-allocation.test.ts — 4/4 passing

Notes

• The error message rewording is the most opinionated change here. If you'd rather keep "manually unallocate that amount," easy to back out — single line in the helper.
• I did not extend the helper to the existing close paths (closeHorizonAllocation and populateUnallocateTransaction) which also call isOverAllocated but with different branching semantics. Worth a separate refactor PR but out of scope for fix: gracefully handle overallocation when reallocating #1203.