Build a Vite application with vite build

[tricknotes]

Command#build drove every build through ember build. In a Vite-based project that command is on its way out. Its own help text says so:

Vestigial command in Vite-based projects. Use the build script from package.json instead.

It now declares only --environment, --suppress-sizes and --output-path, and refuses --watch and --watcher rather than forwarding them (lib/commands/build.js). The blueprint's own script is "build": "vite build" (ember-app-blueprint).

So build a Vite application with vite build. Command#build picks the command from the blueprint, and the two builders sit side by side so what each one needs stays visible.

The flags

Was	Is	Why
--environment	--mode	Same value, from the same build_environment
--output-path	--outDir	The directory Rails serves the application from
—	--emptyOutDir	Required to keep the behaviour we have: the output directory lies outside the Ember application, and Vite leaves stale files there unless asked
--silent	--logLevel error	Quiets the progress output while leaving errors visible

--emptyOutDir is not an improvement, it is parity. Dropping a STALE.txt into the output directory and rebuilding:

Command	STALE.txt
ember build --output-path	removed
vite build --outDir --emptyOutDir	removed
vite build --outDir	left behind

Why not run the build script through a package manager

The gem has to pass --outDir, and forwarding flags to a package.json script is not portable. Measured against the same application, with the command each package manager actually ran:

Command	Ran	Result
npm run build -- <flags>	vite build --outDir … --mode … --emptyOutDir	builds where asked
npm run build <flags>	vite build /tmp/out development	exits 1 — npm eats the flags and passes the values positionally
pnpm build <flags>	vite build --outDir … --mode … --emptyOutDir	builds where asked
pnpm run build -- <flags>	vite build -- --outDir … --mode …	exits 0 and writes to dist — the separator reaches the script

npm needs --, pnpm must not have it, and the pnpm failure is silent. Calling vite directly avoids the whole question, and keeps the DependencyError that PathSet#vite raises when the executable is missing.

Verification

Against the sandbox application (ember-cli 7.2.0, vite 8.2.2):

• rake ember:compile exits 0, running
  …/node_modules/.bin/vite build --mode 'development' --outDir '…/tmp/ember-cli/apps/frontend' --emptyOutDir
• The output is byte-for-byte the same set of files as ember build --environment development --output-path produced — diff of the two file listings, with content hashes normalised, is empty
• The Embroider compat prebuild still runs (Built project successfully. Stored in ".../tmp/compat-prebuild")
• A production build (--mode production) writes index.html plus every asset it references

Tests

• bin/rspec spec/lib/ember_cli/command_spec.rb — 14 examples, 0 failures, including three for the Vite build
• bin/rspec spec/lib — 2 failures, both (app_spec.rb:192, app_spec.rb:200) failing identically on main; they need node_modules installed to find the ember binary

ember test is untouched: it is not vestigial in a Vite project and still works, so rake ember:test keeps running it. The blueprint has begun moving that to testem ci directly, which is worth its own look later.

🤖 Generated with Claude Code