createMainWindow walked the entire renderer generation twice before it
could call loadWindowUrl:
const rendererIndex = DEV_SERVER ? null : resolveRendererIndex()
const tornAssets = rendererIndex ? missingRendererAssets(rendererIndex) : []
resolveRendererIndex already computes exactly that list while choosing the
copy — it needs it to decide whether a copy is torn — and then throws it
away. missingRendererAssets is a BFS that readFileSync's every present
chunk whole and regex-scans it for the inline __vite__mapDeps table, so on
a release tree it is not a stat walk: measured against the real
apps/desktop/dist (252 chunks, 28.7 MiB of JS), one walk is 162
readFileSync calls reading 28.23 MiB, 576 existsSync calls, and 56.6 ms
median (min 55.8, 9 reps, warm page cache, darwin-arm64). Both walks run
synchronously on the main thread before the window gets its URL.
Return the list alongside the index. resolveRendererIndexWithMissing()
carries the existing body and hands back { index, missing }; the
path-only resolveRendererIndex() stays as a one-line wrapper so the nine
other call sites are untouched. The primary-window path takes one
resolution.
Semantics are unchanged in every branch: the same candidate is chosen, the
same log lines are emitted, and the missing list always describes the copy
actually returned. The all-copies-torn branch now reuses the first
candidate's list, captured on the first loop iteration, rather than
recomputing it for present[0] — recomputing there would have reintroduced
the second walk in exactly the case that matters most, and using the
loop's last value would have described a bundle we do not load.
Net effect on every primary-window boot: one fewer full walk, so 162 fewer
readFileSync calls, 28.23 MiB less synchronous reading, 288 fewer
existsSync calls, and ~57 ms of main-thread blocking removed before
loadURL. The win lands on packaged and --prod launches; DEV_SERVER skips
the walk entirely, so `vite dev` is unaffected.
John Paul Soliva
ab4bfda360