hooks.js warning in console when building

[pikeas]

Describe the bug

$ npm run build --verbose
...
vite v2.1.5 building SSR bundle for production...en Completed in 3ms
'getContext' is not exported by '.svelte/build/hooks.js'leted in 3ms
'getSession' is not exported by '.svelte/build/hooks.js'
'handle' is not exported by '.svelte/build/hooks.js'
✓ 14 modules transformed.
.svelte/output/server/app.js   72.24kb

Happens with the static and node adapters.

Expected behavior
No errors.

Information about your SvelteKit Installation:
All libraries are up-to-date (kit @ .73).

Severity
Annoying and may be indicative of a bug in sveltekit, nothing seems to actually be broken.

Additional context
I'm working to reproduce from a fresh repro. Clues:

// .svelte/build/app.js
import * as user_hooks from "./hooks.js";
...
const hooks = {
	getContext: user_hooks.getContext || (() => ({})),
	getSession: user_hooks.getSession || (() => ({})),
	handle: user_hooks.handle || (({ request, render }) => render(request))
};

// .svelte/output/server/app.js
...
const context = await options.hooks.getContext(incoming) || {};

• .svelte/build/hooks.js exists and is empty.
• There is no usage of context in the project.
• I've blown away .svelte, build, functions, and node_modules, which didn't help.
• The vite output is interleaved - two different processes are fighting to write to stderr simultaneously. This may be an unrelated issue.

[pikeas]

Reproduction:

$ npm init svelte@next
# Typescript, CSS, yes, yes
$ npm install
$ npm run build
> foo@0.0.1 build
> svelte-kit build

vite v2.1.5 building for production...
✓ 18 modules transformed.
.svelte/output/client/_app/manifest.json                              1.28kb
.svelte/output/client/_app/pages/$layout.svelte-542a9f8f.js           0.49kb / brotli: 0.29kb
.svelte/output/client/_app/error.svelte-a4e5c48e.js                   1.11kb / brotli: 0.55kb
.svelte/output/client/_app/assets/start-a8cd1609.css                  0.16kb / brotli: 0.10kb
.svelte/output/client/_app/pages/index.svelte-3c4e948d.js             1.71kb / brotli: 0.75kb
.svelte/output/client/_app/assets/pages/$layout.svelte-164b8506.css   0.13kb / brotli: 0.11kb
.svelte/output/client/_app/assets/pages/index.svelte-107d1063.css     0.71kb / brotli: 0.26kb
.svelte/output/client/_app/chunks/vendor-43f860ae.js                  5.22kb / brotli: 2.03kb
.svelte/output/client/_app/start-42c46b07.js                          16.22kb / brotli: 5.13kb
vite v2.1.5 building SSR bundle for production...
transforming (5) .svelte/build/generated/root.svelte'getContext' is not exported by '.svelte/build/hooks.js'
'getSession' is not exported by '.svelte/build/hooks.js'
'handle' is not exported by '.svelte/build/hooks.js'
✓ 16 modules transformed.
.svelte/output/server/app.js   74.78kb

[frederikhors]

It happens from .73 upwards.

[benmccann]

From Rich:
It looks like get_hooks wasn't unnecessary indirection
vite/rollup balks at the hooks.getContext reference if the user doesn't define it. by passing it into the function we get access to the module record without triggering rollup's persnickitiness

[Conduitry]

The 'unnecessary indirection' refers to the simplification I made in #959 (comment)