Startup snapshots for compiled executables (bun build --snapshot) - #37225

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claude/lowmem-cc

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Commits on Aug 7, 2026

Commits on Aug 8, 2026

SNAPSHOT.md: CC cut-point comparison (plain 262 / pre-dispatch 265 / hermetic late cut 48 MB idle)
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SNAPSHOT.md: late cut + hydrate v0 = 56 MB idle
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image: keepTimers — armed timers survive the snapshot and are re-based onto the restoring process's monotonic clock (late-cut apps own timers); test
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image: rebuild the isolated spawnSync event loop after restore (it wrapped the builder's kqueue fd: every spawnSync returned status 1 with no output); hold the JSLock through the 'restore' emit; test
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SNAPSHOT.md: late cut + hydrate v1 runs a real turn at 76 MB idle; runtime bugs it surfaced
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image restore: fresh randomness and time bases per process — reseed Math.random, drop the WebCrypto entropy cache, epoch the fast-random seed, restart origin_timer; chdir through any JS wrapper and…
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image restore prelude: drop the tty _refreshSize call (materializing the tty stream before 'restore' broke stdin under a pty); size refresh stays app-side until done natively
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restore prelude: process.chdir('.') through any installed wrapper (no require in that scope; '.' is the launcher's cwd)
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image restore: flush the getaddrinfo cache (answers came from the builder's network); fetch's build-time guard honors BUN_IMAGE_IO_WARN via the shared helper; test
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misctools/cc-image-demo.sh: plain vs image side-by-side with a real turn; record current numbers (165 vs 276 MB idle once post-mount managers run)
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image: extern-library fixups on Darwin (per-segment table, compacted; shared-cache libs rebased by cache delta without dlopen; cache UUID identity) so images survive reboots; name the offending lib…
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image restore: deliver hangups for dead fds from the event loop after 'restore' (not during adopt); re-arm stdio polls on the re-seated fds; close the dns_sd shared connection at snapshot; test
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image: --compile-image embeds the zstd frame and inflates it into the image cache on first launch; compiled executables not building keep their early heap above image space (an inflating launch cra…
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image: pages are frozen in the builder (MI_THREADID_FROZEN, frees dropped on the existing slow path) instead of a per-free filter — stock fast path; fixup scan runs before the pages are written; li…
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image: envGate snapshot option — the image records the build-time state of the variables the app names and is declined by launches whose environment differs in any of them; test
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mimalloc: hole-sweep state moves from __thread variables onto the swept tld — with the Darwin zone override, a new thread's first malloc that collected a purged page touched a TLV, dyld allocated t…
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mimalloc: frozen image pages are skipped by collect/hole sweeps and removed from the abandoned maps at freeze; the sweep guard looks only at owned pages (an abandoned page may name a theap whose th…
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SNAPSHOT.md: end-of-day state, honest numbers, the day's bug list
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heap image: tests move to test/js/bun/heap-image (test/js/bun/image belongs to the image API and had been overwritten); mimalloc gets generic MI_HEAP_IMAGE_HOST_FN / MI_HEAP_IMAGE_BUILD_ENV hooks t…
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Revert "WIP: bundler prototype: lazy module init (BUN_BUNDLER_LAZY_INIT)"
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docs: --compile-image
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SNAPSHOT.md: fair merge-bar numbers
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heap image: BunMemDebug.cpp becomes HeapImage.{h,cpp} (build + restore) and HeapImageTooling.cpp (attribution commands, compiled only with BUN_HEAPIMAGE_TOOLING=1); clang-formatted
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heap image: plain bun only takes part when asked to via the environment (the previous commit's message described this gate; this is it)
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heap image tooling: enable allocation sampling after restore under BUN_MEMDEBUG; gc command prints the arena maps and live-outside-image bytes; SNAPSHOT.md: where the restored process's memory actu…
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node:tls: bundled root certificates are built once as static strings — no per-call decoding of the bundle and no refcount traffic on them (in a heap image, that traffic was dirtying one page per ce…
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SNAPSHOT.md: the bimodal idle is the claude.ai MCP connectors
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run_command: comment no longer refers to a removed image mode
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mimalloc: pin to oven-sh/mimalloc#13 and stop vendoring the fork's files on this branch — the branch now builds from the download exactly like main does
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Merge origin/main into claude/lowmem-cc
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Revert "node:tls: bundled root certificates are built once as static strings — no per-call decoding of the bundle and no refcount traffic on them (in a heap image, that traffic was dirtying one pag…
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SNAPSHOT.md: note the reverted root-cert experiment
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WebKit: pin to oven-sh/WebKit#397's preview artifact so the branch builds without a local WebKit; SNAPSHOT.md: shipping state
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heap image: remove the experiment knobs from the product path (immortal-refcount mode/range, NOFREEZE, NOFRESHHEAP, FRESHARENA, FIXUPS_DATAONLY, NO_CPU_REPROBE, ZSTD, EVAL, TRACE_EXIT) and four dea…
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Remove working notes and an abandoned experiment patch from the branch
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