Fix #4429: dev server entry detection

[moeriki]

↪️ Pull Request

Fixes #4429.

💻 Examples

Before the entry detection served the first index.html bundle it found.

This would yield a 404 when running any other html file.

parcel serve test.html

I updated the logic, as suggested, to serve any single HTML entry.

🚨 Test instructions

I didn't see any tests for the dev server. Let me know if or where I can do so.

✔️ PR Todo

• Added/updated unit tests for this change
• Filled out test instructions (In case there aren't any unit tests)
• Included links to related issues/PRs

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[moeriki]

I wasn't sure on how to use the bundleGraph. If there is a better way than to use getBundles() I will gladly update.

[DeMoorJasper]

Would be nice to get a test for this.

[mischnic]

Suggested change

	bundle.filePath.endsWith('.html'),
	bundle.type === '.html',

[moeriki]

I will check all your comments and add a few tests.

But now I'm looking at existing tests I broke.

It seems all html bundles have isEntry: true although the tests in question run with a single entry filepath: bundler('/integration/html/index.html'). Would it be possible there is something else going wrong there?

[mischnic]

It seems all html bundles have isEntry: true although the tests in question run with a single entry filepath

isEntry mostly means: no hash.

For example:
https://parcel2-repl.now.sh/#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

generates this bundle graph (a & b are "CLI entries", c is merely linked from a):

But I think the entry_file / entry_specifier part isn't exposed at the moment

[moeriki]

I see.

if there are 2 or more html bundles: 404 (because of the ambiguity, maybe the error page should state this as well)

Per suggest I updated logic from "serve first index.html" to "serve any single HTML bundle".

The problem is there are two tests failing with multiple HTML bundles where it serves a 404 now instead of the first index.html as before.

https://github.com/parcel-bundler/parcel/blob/v2/packages/core/integration-tests/test/server.js#L135
https://github.com/parcel-bundler/parcel/blob/v2/packages/core/integration-tests/test/server.js#L391

Both use the fixtures at integration/html/ which contain both index.html and other.html. I hoped isEntry would filter out the other, but it doesn't. Not sure how to filter this correctly.