Fix actions concurrency groups cross-branch leak (#37311)

[GiteaBot]

Backport #37311 by @silverwind

Problem

Workflow-level concurrency groups were evaluated — and jobs were parsed — before the run was persisted, so run.ID was 0 and github.run_id in the expression context resolved to an empty string. Expressions like:

concurrency:
  group: ${{ github.workflow }}-${{ github.head_ref || github.run_id }}
  cancel-in-progress: true

collapsed to <workflow>- on every push event (head_ref is empty on push), so cancel-in-progress cancelled in-progress runs across unrelated branches, not just the current one.

Reproduced on a 1.26 instance:

• push to master → ci run starts
• push to feature-branch → the master run gets cancelled

GitHub Actions' documented semantic: on push events github.run_id is unique per run, so the group is unique → no cancellation; on PR events github.head_ref is the source branch → cancellation is per-PR.

Fix

Insert the run before parsing jobs or evaluating workflow-level concurrency, so run.ID is populated in time for every expression that reads github.run_id — not just the concurrency group, but also run-name, job names, and runs-on.

jobparser.Parse now runs inside the InsertRun transaction, after db.Insert(ctx, run). Workflow-level concurrency evaluation runs next and only mutates run in memory. All concurrency-derived fields (raw_concurrency, concurrency_group, concurrency_cancel) plus status and title are persisted in a single final UpdateRun at end-of-transaction — one INSERT + one UPDATE per run in both the concurrency and non-concurrency paths (matches pre-branch parity, one fewer UpdateRepoRunsNumbers COUNT than the interim state).

GenerateGiteaContext now sets run_id from run.ID unconditionally; every caller passes a persisted run.

Verification: tested end-to-end on a 1.26 deployment. Before the patch, two successive ci pushes (one to master, one to a feature branch) cross-cancelled each other. After the patch, the same pushes — in both orders (master→branch, branch→master) — run to completion simultaneously across 15+ runs with zero cancellations.

Regression tests in services/actions/context_test.go:

• TestEvaluateRunConcurrency_RunIDFallback — unit check that EvaluateRunConcurrencyFillModel resolves github.run_id from run.ID.
• TestPrepareRunAndInsert_ExpressionsSeeRunID — full-flow check: calls PrepareRunAndInsert with ${{ github.run_id }} in both run-name and the concurrency group, then asserts the persisted Title, ConcurrencyGroup, and RawConcurrency contain / survive the run's ID. Re-ordering db.Insert relative to either parse or concurrency eval fails this test.

Relation to #37119

#37119 also moves concurrency evaluation into InsertRun but keeps it before db.Insert, then tries to populate run_id only when run.ID > 0 — which is still 0 at that call site, so the cross-branch leak would survive that PR as written. This PR fixes the ordering so that run.ID is actually populated at eval time, and broadens it to cover parse-time expression interpolation too.

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This PR was written with the help of Claude Opus 4.7