Watcher does not rebuild when file in subdirectory is written atomically

[WhyNotHugo]

Describe the bug

When I edit file src/composables/usePhotoStore.ts, npm exec -- vite build --watch --mode development doesn't rebuild.

If I edit src/main.ts, a rebuild is triggerd.

I narrowed this down to a minimal reproducer. This only happens when atomically writing (e.g.: write to new file, then replace) a file in a subdirectory.

Reproduction

https://paste.sr.ht/~whynothugo/52c200f2edc65bee7da6893134afa1cc7e8ce873

Steps to reproduce

Use reproducer above or:

• Run npm exec -- vite build --watch
• Edit file in nested directory with vim (which does atomic writes)

System Info

# npx envinfo --system --npmPackages '{vite,@vitejs/*,rollup,rolldown}' --binaries --browsers
Need to install the following packages:
envinfo@7.21.0
Ok to proceed? (y) y

  System:
    OS: Linux 7.1 Alpine Linux
    CPU: (24) x64 13th Gen Intel(R) Core(TM) i7-13700K
    Memory: 22.13 GB / 62.54 GB
    Container: Yes
    Shell: Unknown - /bin/sh
  Binaries:
    Node: 24.16.0 - /usr/local/bin/node
    Yarn: 1.22.22 - /usr/local/bin/yarn
    npm: 11.13.0 - /usr/local/bin/npm
  npmPackages:
    @vitejs/plugin-vue: ^6.0.8 => 6.0.8 
    vite: ^8.2.1 => 8.2.1

Used Package Manager

npm

Logs

No response

Validations

• Follow our Code of Conduct
• Read the Contributing Guidelines.
• Read the docs.
• Check that there isn't already an issue that reports the same bug to avoid creating a duplicate.
• Make sure this is a Vite issue and not a framework-specific issue. For example, if it's a Vue SFC related bug, it should likely be reported to vuejs/core instead.
• Check that this is a concrete bug. For Q&A open a GitHub Discussion or join our Discord Chat Server.
• The provided reproduction is a minimal reproducible example of the bug.

[santhiprakash]

Could not reproduce this on vite 8.2.1, on either glibc or musl/Alpine.

Reproduction matrix (all runs: vite build --watch --mode development, entry src/main.ts importing src/composables/usePhotoStore.ts):

write pattern	depth-1 (src/main.ts)	depth-2 (src/composables/usePhotoStore.ts)
in-place write	rebuild	rebuild
atomic write (write temp file, rename over original)	rebuild	rebuild
vim-style (rename original to *.ts~, create new file, unlink backup)	—	rebuild

Environments tested:

• Ubuntu (glibc), Node 22.22, kernel 6.17
• node:24-alpine container (musl), Node 24.19, kernel 6.17 — closest to your setup apart from the kernel (your envinfo reports Linux 7.1)

One case does match the symptom: when the edited file is not reachable from the entry (not part of the module graph), an atomic write in a subdirectory does not trigger a rebuild. That looks like expected behavior — in vite 8 build --watch delegates watching to rolldown's native watcher over the module graph (the chokidar options are only used for usePolling/interval via convertToWatcherOptions), so a file nothing imports is not watched.

The paste link in the issue body returns 404 for me, so I can't check the minimal reproducer directly. Two questions that would pin this down:

1. In the minimal reproducer, is src/composables/usePhotoStore.ts imported (directly or transitively) from the entry?
2. If yes — does it still fail for you when the atomic write targets the imported file specifically?

If it persists with the file imported, the kernel version may be the remaining variable (7.1 here vs 6.17 in my tests), since rename-event delivery comes from the native (inotify-based) watcher.

[WhyNotHugo]

I can't explain why the reproducer returns 404 for you; it (still) works fine here. Pasting it inline here:

#!/bin/sh
# Reproducer for "Watcher does not rebuild when file in subdirectory is written atomically"
# Tested only on Alpine Linux
set -eu
dir=$(mktemp -d)
echo "working in $dir"
cd "$dir"

echo '{ "name": "repro", "type": "module" }' > package.json
npm install --no-audit --no-fund vite@8.2.1 >/dev/null
mkdir -p src/sub
echo 'export default { build: { rollupOptions: { input: ["src/main.ts"] } } };' > vite.config.mjs

# single module, so the watcher registers only the src/ directory
echo 'console.log(0);' > src/main.ts

./node_modules/.bin/vite build --watch >vite.log 2>&1 &
pid=$!
trap 'kill $pid 2>/dev/null' EXIT
until grep -q 'built in' vite.log; do sleep 1; done

builds() { grep -c 'built in' vite.log || true; }
wait_builds() { i=0; while [ "$(builds)" -lt "$1" ] && [ "$i" -lt 20 ]; do sleep 1; i=$((i+1)); done; }

# introduce a module in a subdirectory while the watcher runs.
# src/ already has a watch handle, so src/sub is skipped and dep.ts gets a
# fragile per-file watch.
echo 'export const x = 1;' > src/sub/dep.ts
echo 'import { x } from "./sub/dep"; console.log(x);' > src/main.ts
wait_builds 2

# sanity check: an in-place edit of dep.ts triggers a rebuild
echo 'export const x = 2;' > src/sub/dep.ts
wait_builds 3
[ "$(builds)" -ge 3 ] || { echo "setup broken: in-place edit did not rebuild"; exit 1; }

# replace dep.ts by rename, preserving content (simulate editor atomic save)
mv src/sub/dep.ts dep.tmp && cp dep.tmp src/sub/dep.ts && rm dep.tmp
sleep 3
before=$(builds)

# this edit should trigger a rebuild but never does
echo 'export const x = 3;' > src/sub/dep.ts
sleep 3

echo "source now:  $(cat src/sub/dep.ts)"
echo "bundle has:  $(grep -ho 'console.log(.)' "dist/assets/$(ls -t dist/assets | head -1)")"
if [ "$(builds)" -gt "$before" ]; then
  echo "NOT reproduced: edit after replace-by-rename triggered a rebuild"
  exit 1
else
  echo "BUG reproduced: edit after replace-by-rename triggered no rebuild"
fi

[WhyNotHugo]

In the minimal reproducer, is src/composables/usePhotoStore.ts imported (directly or transitively) from the entry?

In my original reproducer: yes. The whole point of the issue is that I see stale builds. In the minimal reproducer files have different names, but it's also part of the build.

If yes — does it still fail for you when the atomic write targets the imported file specifically?

Correct.