segment prop is initially incorrect on client-side layout for server-rendered error pages

[jarrodldavis]

When hydrating the client-side app from a server-side rendered error page, the segment prop provided to _layout.svelte is incorrect (for me, it's undefined).

The issue appears to be here:

sapper/runtime/src/app/app.ts

Lines 134 to 150 in 49f8b2c

	const props = {
	error,
	status,
	session,
	level0: {
	props: root_preloaded
	},
	level1: {
	props: {
	status,
	error
	},
	component: ErrorComponent
	},
	segments: preloaded
	}

which is vastly different than the normal logic used to create the props.segments array:

sapper/runtime/src/app/app.ts

Lines 259 to 263 in 49f8b2c

	const segments = page.path.split('/').filter(Boolean);
	let redirect: Redirect = null;
	const props = { error: null, status: 200, segments: [segments[0]] };

sapper/runtime/src/app/app.ts

Lines 291 to 293 in 49f8b2c

	branch = await Promise.all(route.parts.map(async (part, i) => {
	props.segments[l] = segments[i + 1]; // TODO make this less confusing
	if (!part) return null;

preloaded appears to be, as the name suggests, the results of invocations of preload functions, as appropriate, for components rendered server side and serialized to the client.

[t-heuser]

Same for me in a freshly installed sapper environment.

[ajbouh]

I've been working getting sapper to compile with TypeScript in strict mode and also came across this surprising assignment.

I haven't been able to find any documentation about what the contract for segments is, so it's been a challenge to fix it. Does anyone subscribed to this issue have any suggestions?

[pngwn]

Segment might not be around for much longer: #824

[pngwn]

Oh hey, it was that issue's birthday yesterday.

[lmf-git]

Happy birthday. Getting this error on fresh install for zero reason. :)