fix(pages-router): add bounded eviction to client-side data cache (sdc/sbc)#95355
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fix(pages-router): add bounded eviction to client-side data cache (sdc/sbc)#95355sleitor wants to merge 1 commit into
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…c/sbc) The sdc/sbc (Server Data Cache / Server Background Cache) objects in the Pages Router grew without bound: every route visited added a Promise to the plain-object cache and nothing ever removed them, causing a memory leak that grows with the number of unique pages visited in a long-lived session (issue vercel#91484, reported by iamakulov). This change wraps the cache initializer in a Proxy-based factory (createDataCache) that enforces a maximum of 50 cache entries using a FIFO eviction policy. When the 51st unique key is written, the oldest entry is deleted before the new one is stored. All existing call sites that read, write, or delete cache keys via bracket notation continue to work without modification. The constant SDC_MAX_ENTRIES (50 routes) matches common LRU sizes used in other parts of the codebase and is conservative enough to avoid any observable regressions while still bounding memory use to a reasonable level for production sessions. Fixes vercel#91484
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The
sdc/sbc(Server Data Cache / Server Background Cache) objects in the Pages Router grew without bound: every route visited added a Promise to the plain-object cache and nothing ever removed them, causing a memory leak that grows with the number of unique pages visited in a long-lived session (reported in #91484 by @iamakulov).What
Wraps the cache initializer in a Proxy-based factory (
createDataCache) that enforces a maximum of 50 cache entries using a FIFO eviction policy. When the 51st unique key is written, the oldest entry is deleted before the new one is stored. All existing call sites that read, write, or delete cache keys via bracket notation continue to work without modification.The constant
SDC_MAX_ENTRIES(50 routes) matches common LRU sizes used in other parts of the codebase and is conservative enough to avoid observable regressions while still bounding memory use for production sessions.Why
Previously there was no eviction at all — the cache was a plain object with no size limit. This is a low-risk, zero-call-site-change fix.
Fixes #91484