[plugin-vue] should not inject HMR code if the server is started with hmr: false

[haoqunjiang]

Describe the bug

Currently, @vitejs/plugin-vue only checks for the existence of options.devServer (which is a ViteDevServer instance) to decide whether to inject HMR code, regardless of the actual configuration of the server.

Meanwhile, there's a server option that can disable HMR completely:

vite/packages/vite/src/node/server/index.ts

Line 74 in e2b3628

hmr?: HmrOptions | boolean

and it is respected in the core vite server:

vite/packages/vite/src/node/server/index.ts

Lines 370 to 380 in e2b3628

	if (serverConfig.hmr !== false) {
	try {
	await handleHMRUpdate(file, server)
	} catch (err) {
	ws.send({
	type: 'error',
	err: prepareError(err)
	})
	}
	}
	})

but never checked in plugin-vue:

vite/packages/plugin-vue/src/main.ts

Lines 116 to 136 in e2b3628

	// HMR
	if (devServer && !ssr && !isProduction) {
	output.push(`_sfc_main.__hmrId = ${JSON.stringify(descriptor.id)}`)
	output.push(
	`typeof __VUE_HMR_RUNTIME__ !== 'undefined' && ` +
	`__VUE_HMR_RUNTIME__.createRecord(_sfc_main.__hmrId, _sfc_main)`
	)
	// check if the template is the only thing that changed
	if (prevDescriptor && isOnlyTemplateChanged(prevDescriptor, descriptor)) {
	output.push(`export const _rerender_only = true`)
	}
	output.push(
	`import.meta.hot.accept(({ default: updated, _rerender_only }) => {`,
	` if (_rerender_only) {`,
	` __VUE_HMR_RUNTIME__.rerender(updated.__hmrId, updated.render)`,
	` } else {`,
	` __VUE_HMR_RUNTIME__.reload(updated.__hmrId, updated)`,
	` }`,
	`})`
	)
	}

vite/packages/plugin-vue/src/template.ts

Lines 23 to 27 in e2b3628

	if (options.devServer && !ssr && !options.isProduction) {
	returnCode += `\nimport.meta.hot.accept(({ render }) => {
	__VUE_HMR_RUNTIME__.rerender(${JSON.stringify(descriptor.id)}, render)
	})`
	}

This causes problems as I'm working on vite-jest.
I need the transpiled code to run in the Node.js environment, which doesn't support import.meta.hot. But because of this bug, I can't disable HMR completely in Vue projects.

Reproduction

N/A

System Info

Output of npx envinfo --system --npmPackages vite,@vitejs/plugin-vue --binaries --browsers:

  System:
    OS: macOS 11.2.3
    CPU: (8) x64 Intel(R) Core(TM) i7-6820HQ CPU @ 2.70GHz
    Memory: 131.21 MB / 16.00 GB
    Shell: 5.8 - /bin/zsh
  Binaries:
    Node: 15.12.0 - ~/n/bin/node
    Yarn: 1.22.10 - /usr/local/bin/yarn
    npm: 7.6.3 - ~/n/bin/npm
  Browsers:
    Chrome: 89.0.4389.90
    Chrome Canary: 91.0.4463.0
    Firefox: 85.0
    Firefox Developer Edition: 86.0
    Safari: 14.0.3

Used package manager: pnpm

---

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