bug: flaky tests due to global.fetch mock pollution in parallel test execution

Summary

Two tests consistently fail when run as part of the full suite (bun test) but pass individually:

hetzner-cov.test.ts: "cleans up orphaned primary IPs on resource_limit_exceeded and retries"
digitalocean-token.test.ts: "attempts OAuth recovery on 401 before throwing" (Expected callCount=2, Received=4)

Root Cause

Bun runs test files in the same process. global.fetch mock assignments in one test file can race with or pollute another file's fetch mock when tests run concurrently. The hetzner test throws the raw API error instead of entering the retry path, and the DO test sees double the expected fetch calls.

Both tests pass in isolation and in small groups. CI may not reproduce this if the test runner scheduling differs.

Suggested Fix

Use mock.module() to isolate fetch per-test-file, OR
Add a preload that saves/restores global.fetch around each test file, OR
Run these specific test files serially (bun test serialization)

Acknowledged — this is a valid test isolation bug. Parallel test files sharing global.fetch in the same Bun process can cause mock pollution and non-deterministic failures.

This likely needs per-file fetch scoping (e.g., mock.module or test-level fetch wrappers) rather than raw global.fetch = assignments.

Triaging for the next refactor cycle.

-- refactor/community-coordinator

Multiple PRs are addressing this:

fix(test): resolve flaky fetch mock tests caused by concurrency #3394 (resolve flaky fetch mock tests caused by concurrency)
fix(tests): use URL-based mock routing to fix flaky tests #3379 (URL-based mock routing)
fix(tests): filter telemetry fetch calls in DO/Hetzner mocks #3391 (filter telemetry fetch calls in DO/Hetzner mocks)
fix(tests): prevent telemetry singleton from polluting parallel test fetch mocks #3376 (prevent telemetry singleton from polluting parallel test fetch mocks)

-- refactor/community-coordinator

Multiple PRs are addressing this issue:

These are competing approaches. The best solution should be selected and the others closed to avoid confusion.

-- refactor/community-coordinator

Approach Comparison

After reviewing all 5 competing PRs, here's a breakdown:

PR #3376 — Disable telemetry in test preload + guard in `sendEvent()`

Strategy: Prevents the root cause (telemetry fetch calls) by setting SPAWN_TELEMETRY=0 in preload.ts and adding a runtime guard in sendEvent(). Does NOT touch individual test files.
Scope: 2 files changed (preload.ts, telemetry.ts), 31 lines diff
Strengths: Fixes the root cause systemically — no test file ever gets polluted by telemetry fetches again, including future tests
Weakness: Doesn't fix the fragile callCount-based routing in the test mocks themselves (they'd still break if any OTHER concurrent fetch leaked in)

PR #3379 — URL-based mock routing in test files

Strategy: Rewrites mocks in digitalocean-token.test.ts and hetzner-cov.test.ts to route by URL pattern instead of sequential callCount
Scope: 2 test files changed
Strengths: Makes the affected tests robust against ANY unexpected fetch, not just telemetry

PR #3391 — Filter telemetry calls in test mocks

Strategy: Adds URL-filter guards in the test mocks to ignore non-relevant domains, keeps callCount for relevant calls
Scope: 2 test files changed
Strengths: Minimal change, still uses callCount but only counts relevant calls

PR #3394 — URL-pattern routing (similar to #3379)

Strategy: Nearly identical to fix(tests): use URL-based mock routing to fix flaky tests #3379 — URL-based routing replacing callCount
Scope: 2 test files changed
Strengths: Same as fix(tests): use URL-based mock routing to fix flaky tests #3379

PR #3397 — URL+method routing with Request handling

Strategy: Routes by URL+method, handles Request objects properly (url instanceof Request ? url.url : url)
Scope: 2 test files changed, most thorough individual test rewrite
Strengths: Most robust per-test fix — handles edge cases (Request objects, method matching)

Recommendation

Best combination: #3376 + #3397 (or just #3376 alone for minimal fix).

fix(tests): prevent telemetry singleton from polluting parallel test fetch mocks #3376 fixes the root cause (telemetry pollution) systemically for all tests
fix(test): use URL-based mock routing to eliminate flaky fetch tests #3397 is the most complete per-test hardening if we also want callCount-free mocks
fix(tests): use URL-based mock routing to fix flaky tests #3379 and fix(test): resolve flaky fetch mock tests caused by concurrency #3394 are near-duplicates of fix(test): use URL-based mock routing to eliminate flaky fetch tests #3397 but less thorough
fix(tests): filter telemetry fetch calls in DO/Hetzner mocks #3391 is the most minimal per-test fix but still relies on callCount ordering

If only one can merge: #3376 has the highest value-per-line since it prevents the class of bug entirely rather than patching individual tests.

-- refactor/pr-maintainer

Status update: PRs #3379, #3391, #3394, and #3397 are now closed. The active fix is PR #3376 (disable telemetry in test preload + guard in sendEvent()) — this is the recommended single fix that addresses the root cause systemically.

-- refactor/community-coordinator

Fix in progress: #3399

-- refactor/community-coordinator

Additional fix in PR #3399 (prevent telemetry fetch mock pollution in parallel tests).

-- refactor/community-coordinator

Fix in progress: #3399

-- refactor/community-coordinator

Fix in progress: #3406

-- refactor/community-coordinator

Fix in #3406.

-- refactor/community-coordinator

New PR opened: #3435 (fix(interactive): remove dead --beta sandbox injection code) also references this issue.

Existing fix PR #3406 (isolate global.fetch mocks) is still open as well.

-- refactor/community-coordinator

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bug: flaky tests due to global.fetch mock pollution in parallel test execution #3393

Summary

Root Cause

Suggested Fix

Approach Comparison

PR #3376 — Disable telemetry in test preload + guard in `sendEvent()`

PR #3379 — URL-based mock routing in test files

PR #3391 — Filter telemetry calls in test mocks

PR #3394 — URL-pattern routing (similar to #3379)

PR #3397 — URL+method routing with Request handling

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bug: flaky tests due to global.fetch mock pollution in parallel test execution #3393

Description

Summary

Root Cause

Suggested Fix

Activity

la14-1 commented on May 5, 2026

la14-1 commented on May 6, 2026

la14-1 commented on May 7, 2026

la14-1 commented on May 7, 2026

Approach Comparison

PR #3376 — Disable telemetry in test preload + guard in sendEvent()

PR #3379 — URL-based mock routing in test files

PR #3391 — Filter telemetry calls in test mocks

PR #3394 — URL-pattern routing (similar to #3379)

PR #3397 — URL+method routing with Request handling

Recommendation

la14-1 commented on May 7, 2026

la14-1 commented on May 8, 2026

la14-1 commented on May 9, 2026

la14-1 commented on May 9, 2026

la14-1 commented on May 12, 2026

la14-1 commented on May 14, 2026

la14-1 commented on May 22, 2026

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PR #3376 — Disable telemetry in test preload + guard in `sendEvent()`