CI: add a targeted retry to `clone-gitlab-repo` so Gitaly load-shedding does not fail the pipeline
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## Summary
`clone-gitlab-repo` is the single point where `gitlab-org/gitlab` CI clones from Gitaly. When Gitaly load-sheds, that job exhausts its three `get_sources` attempts and fails with `exit code 128` — and because the runner reports the failure as `script_failure`, our `.default-retry` `when:` list does **not** cover it, so the job gets no job-level retry and the whole pipeline dies.
Proposal: add a targeted `retry` to `clone-gitlab-repo` (and only that job) covering `script_failure`.
## Why `clone-gitlab-repo` is a choke point
`.gitlab-ci.yml` sets `CI_FETCH_REPO_GIT_STRATEGY: "none"`, and `.repo-from-artifacts` wires every other job to take the repo from an artifact:
```yaml
# .gitlab/ci/global.gitlab-ci.yml
.repo-from-artifacts:
variables:
GIT_STRATEGY: "${CI_FETCH_REPO_GIT_STRATEGY}"
needs:
- clone-gitlab-repo
```
So one job clones and everything else depends on its artifact. A single `bad pack header` there fails the pipeline, and downstream jobs report `missing_dependency_failure` rather than a git error — which makes these harder to attribute than they should be.
## The gap
`.gitlab/ci/global.gitlab-ci.yml`:
```yaml
.default-retry:
retry:
max: 2
when:
- api_failure
- data_integrity_failure
- runner_system_failure
- scheduler_failure
- stuck_or_timeout_failure
- unknown_failure
```
`clone-gitlab-repo` inherits this via `.absolutely-predictive-job` → `.predictive-job` → `.default-retry`. But `script_failure` is absent from the list.
Every one of the last 12 `git_issues_network_error` jobs on `gitlab-org/gitlab` in the analytics ClickHouse carries `failure_reason = script_failure`. Confirmed against three job traces from 2026-09-04 12:20–12:31 UTC (`16306740250`, `16306630037`, `16306908779`):
```
remote: error executing git hook
remote: error resource exhausted, please try again later
remote: aborting due to possible repository corruption on the remote side.
fatal: protocol error: bad pack header
...
ERROR: Job failed: exit code 128
```
## What the in-job retries already do
`GET_SOURCES_ATTEMPTS: "3"` (`.gitlab-ci.yml`) is handled runner-side in `common/build.go` (`attemptExecuteStage`, wrapping only `BuildStageGetSources`). Exponential backoff between those attempts is already active — `FF_USE_EXPONENTIAL_BACKOFF_STAGE_RETRY` defaults to `true`, 5s→5min (gitlab-org/gitlab#422510, closed complete). The observed gaps were 5s then 10s.
The problem is not backoff spacing. It's that all three attempts land inside a ~3 minute window while a load-shedding episode lasts far longer, and then there is no outer retry:
```
12:27:49 get_sources → 12:28:50 fatal (61s)
12:28:55 Deleting tracked and untracked files...
12:28:55 get_sources → 12:29:56 fatal (61s)
12:30:06 get_sources → 12:31:07 fatal (61s)
→ exit 128, pipeline fails
```
A job-level retry re-queues the job minutes later, which is the timescale these episodes actually resolve on.
## Proposal
```yaml
clone-gitlab-repo:
extends:
- .absolutely-predictive-job
- .setup:rules:clone-gitlab-repo
retry:
max: 2
when:
- api_failure
- data_integrity_failure
- runner_system_failure
- scheduler_failure
- stuck_or_timeout_failure
- unknown_failure
- script_failure # get_sources exhaustion surfaces as script_failure
```
Scoping `script_failure` to this one job matters: adding it to `.default-retry` globally would retry genuine test and lint failures, which we do not want.
### Trade-offs
- `clone-gitlab-repo` has no `script:` of its own beyond a three-line git-config cleanup, so `script_failure` here is almost always `get_sources`. The blast radius of a false retry is small.
- It does mean up to 9 clone attempts (3 job runs × 3 `GET_SOURCES_ATTEMPTS`) in the worst case. If that is judged too aggressive against an already-shedding Gitaly, the alternative is `retry: max: 1` plus lowering `GET_SOURCES_ATTEMPTS` for this job, keeping total attempts at 6 but spread over a longer window.
- Every attempt is a **fresh full clone** (`GIT_STRATEGY: clone` + the worktree wipe between attempts), so each one costs a full ~61s and real Gitaly load. Spacing matters more than count.
## Context
This is the `git_issues_network_error` bucket in the weekly master CI failure reports (gitlab-org/quality/analytics/team). It is bursty rather than steady — hourly counts on `gitlab-org/gitlab` for 2026-09-03: `09:00 → 53`, `12:00 → 27`, `14:00 → 52`, `16:00 → 31`, **`17:00 → 108`**, `19:00 → 12`. The underlying Gitaly-side cause is tracked separately (see gitlab-org/packhorse#78); this issue is only about our CI config not surviving those episodes.
Note also that [gitlab-runner#39593](https://gitlab.com/gitlab-org/gitlab-runner/-/work_items/39593) (the `rm` flood that used to blow the 4 MiB job-log cap and hide these failures under `logs_too_big_to_analyze`) was fixed in gitlab-runner v19.3.0, and the shared fleet is now on 19.4.0. These failures are visible in traces again.
issue
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