Keep stale virtual member copy when the remote lookup fails #171

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benvin merged 3 commits from benvin/stale-keep-on-lookup-error into master 2026-10-25 20:24:20 +11:00

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unkin-agent commented 2026-10-25 19:07:26 +11:00

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A transient remote lookup error dropped the serve_stale copy of a virtual member and forced a blocking fetch, so a short DB blip stalled every merge.

• serve the existing copy on a lookup error and refresh it in the background
• fetch directly without storing anything on a lookup error with no copy
• create copies only after a successful lookup with serve_stale on

A transient remote lookup error dropped the serve_stale copy of a virtual member and forced a blocking fetch, so a short DB blip stalled every merge. - serve the existing copy on a lookup error and refresh it in the background - fetch directly without storing anything on a lookup error with no copy - create copies only after a successful lookup with serve_stale on

unkin-agent added 1 commit 2026-10-25 19:07:26 +11:00

Keep stale virtual member copy when the remote lookup fails de80fd84c2

unkin-agent commented 2026-10-25 19:11:29 +11:00

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• internal/virtual/engine.go:552 — a lookup error now routes a member with serve_stale off into the stale path: it serves a leftover warm copy (from a past toggle) up to maxStaleAge, and a cold fetch stores a new copy for it → state this explicitly as intended, or on error with no existing copy call fetch(ctx) directly without storing.
• internal/virtual/engine_stale_test.go:331 — only the warm-copy case is covered; add a lookup-error case for a cold member (blocks, no stale copy retained or retained as intended) and for a member with serve_stale off → pin the chosen behaviour.

- internal/virtual/engine.go:552 — a lookup error now routes a member with `serve_stale` off into the stale path: it serves a leftover warm copy (from a past toggle) up to maxStaleAge, and a cold fetch stores a new copy for it → state this explicitly as intended, or on error with no existing copy call `fetch(ctx)` directly without storing. - internal/virtual/engine_stale_test.go:331 — only the warm-copy case is covered; add a lookup-error case for a cold member (blocks, no stale copy retained or retained as intended) and for a member with `serve_stale` off → pin the chosen behaviour.

unkin-agent added 1 commit 2026-10-25 19:16:20 +11:00

Create virtual member stale copies only after a successful serve_stale lookup f1fd1a442c

unkin-agent commented 2026-10-25 19:20:15 +11:00

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• internal/virtual/engine_stale_test.go:332 — TestServeStaleLookupErrorKeepsCopy cannot tell "served copy + background refresh" from "blocking direct fetch that leaves the copy alone": fetch returns constant content and calls is never checked, so the repomd equality and the copy-still-present assertion hold either way → use a blocking/changing fetch (as TestServeStaleMemberDoesNotBlockMerge does) and assert the merge returns without waiting, or assert the post-refresh copy is newer.
• nit: internal/virtual/engine.go:565 — the lookup-error-with-in-flight-placeholder path (prev != nil, prev.m == nil) falls through to the direct fetch but has no test → add one.

- internal/virtual/engine_stale_test.go:332 — TestServeStaleLookupErrorKeepsCopy cannot tell "served copy + background refresh" from "blocking direct fetch that leaves the copy alone": fetch returns constant content and calls is never checked, so the repomd equality and the copy-still-present assertion hold either way → use a blocking/changing fetch (as TestServeStaleMemberDoesNotBlockMerge does) and assert the merge returns without waiting, or assert the post-refresh copy is newer. - nit: internal/virtual/engine.go:565 — the lookup-error-with-in-flight-placeholder path (prev != nil, prev.m == nil) falls through to the direct fetch but has no test → add one.

unkin-agent added 1 commit 2026-10-25 19:23:17 +11:00

Prove lookup-error stale serving and cold-fetch isolation in tests b54eb5fe2f

unkin-agent commented 2026-10-25 19:26:24 +11:00

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No findings.

No findings.

benvin merged commit f5d30cc96e into master 2026-10-25 20:24:20 +11:00

benvin deleted branch benvin/stale-keep-on-lookup-error 2026-10-25 20:24:21 +11:00

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Reference: unkin/artifactapi#171