[Bug] Issue Discovery Credits Issues Solved by PRs Merged Into Non-Scoring Branches

[Helios531]

Summary

The mirror issue API returns an inline solving_pr for any merged PR that closed an issue, but it neither filters nor exposes the solving PR’s base_ref / default_branch.

This breaks parity with the OSS PR scoring path, where merged PRs are rejected if they target a non-acceptable branch. In gittensor, issue discovery only checks that solving_pr.state == "MERGED" and then scores it, so an issue can receive discovery credit even when the solving PR would be rejected from PR scoring because it merged into a non-scoring branch.

Reproduction Steps

1. Run the DAS locally with local Postgres/Redis and a dummy GitHub App key:
2. Seed a repo, a closed issue, and a solving PR merged into a non-scoring branch:
3. Query the mirror issue endpoint:

curl -sS \
  'http://127.0.0.1:6970/api/v1/miners/111/issues?since=2026-05-01T00:00:00Z'

4. Validate the same shape in gittensor:
5. Compare with normal PR scoring branch eligibility:

Actual Result

The mirror returns a solving_pr for the non-scoring-branch PR:

{
  "issue_number": 9,
  "state": "CLOSED",
  "state_reason": "COMPLETED",
  "solved_by_pr": 7,
  "solving_pr": {
    "pr_number": 7,
    "author_github_id": "222",
    "state": "MERGED",
    "merged_at": "2026-05-20T01:00:00+00:00",
    "edited_after_merge": false,
    "head_sha": "1111111111111111111111111111111111111111",
    "base_sha": "2222222222222222222222222222222222222222",
    "merge_base_sha": "3333333333333333333333333333333333333333"
  }
}

gittensor classifies and adapts it as scoreable:

classification: solved
adapted: True
discovery_base_score: 42.0

But the same PR is rejected by normal OSS PR scoring:

oss_pr_skip: True
reason: PR #7 merged to 'scratch-do-not-score' not in acceptable branches=['main']

Expected Result

Issue discovery should not award solved-issue credit for a PR that would fail the same merged-PR branch eligibility gate used by OSS contribution scoring.

Evidence

Local project execution:

Nest application successfully started
Bootstrap listening on port 6970
/api/v1/health returned 200 with db.ok=true and redis.ok=true

Root Cause

packages/das/src/api/miners/miners.service.ts builds inline solving_pr with only minimal fields. It does not include base_ref, head_ref, head_repo_full_name, or default_branch, and it does not filter by branch eligibility in SQL.

Relevant local files:
[miners.service.ts] (https://github.com/entrius/das-github-mirror/packages/das/src/api/miners/miners.service.ts):115

[gittensor issue discovery] (https://github.com/entrius/gittensor/gittensor/validator/issue_discovery/scan.py):692

[gittensor PR branch gate] (https://github.com/entrius/gittensor/gittensor/validator/oss_contributions/mirror/scoring.py):236

Security/Business Impact

This is a reward-integrity bug. A miner can receive issue-discovery credit for issues closed by PRs merged into branches that are explicitly not accepted for normal contribution scoring. That creates an inconsistent scoring policy and a practical bypass of repository branch restrictions.

Suggested Fix

Add solving PR branch eligibility to the issue-discovery path.

Recommended DAS-side fix:

• Include base_ref, head_ref, head_repo_full_name, and default_branch in inline solving_pr.
• Or filter solving_pr server-side so only PRs merged into acceptable branches are returned.
• Keep the validation rule aligned with _should_skip_merged_mirror_pr.

Recommended gittensor-side defense-in-depth:

• Extend MirrorSolvingPR with branch fields.
• Apply the same base/head branch gate before _classify_issue returns solved or before _mirror_issue_for_scoring adapts the issue.