@wordpress/scripts doesn't detect render PHP files without a restart

[aurooba]

Description

If you have @wordpress/scripts running with the start script, and add a "render": "file:./render.php" to your block.json file, the script doesn't detect it. But if you end the process and restart it, then it does.

It's very possible I'm just missing something, but I can't figure out why this is happening! I don't recall it being an issue before.

Step-by-step reproduction instructions

1. Create a new block plugin with npx @wordpress/create-block todo-list
2. Run npm run start
3. Add a render.php file in the src folder
4. Add "render": "file:./render.php" to your block.json file.
5. See that the render.php never makes it to the build folder
6. Kill the script in your terminal
7. Run npm run start again.
8. See that the render.php now appears in your build folder

Screenshots, screen recording, code snippet

block.json

{
	"$schema": "https://schemas.wp.org/trunk/block.json",
	"apiVersion": 2,
	"name": "create-block/todo-list",
	"version": "0.1.0",
	"title": "Todo List",
	"category": "widgets",
	"icon": "smiley",
	"description": "Example block scaffolded with Create Block tool.",
	"supports": {
		"html": false
	},
	"textdomain": "todo-list",
	"editorScript": "file:./index.js",
	"editorStyle": "file:./index.css",
	"style": "file:./style-index.css",
	"render": "file:./render.php"
}

render.php

<?php
echo 'Hello World!';

Screenshot of the src folder

Environment info

• WordPress 6.2

Please confirm that you have searched existing issues in the repo.

Yes

Please confirm that you have tested with all plugins deactivated except Gutenberg.

Yes

[gziolo]

Thank you for opening this issue, @aurooba. I haven’t tested it yet but I’m quite sure that the issue exists based on the following findings in the code.

There is a single place in the webpack config that collects all paths for all render occurrences in existing block.json files:

gutenberg/packages/scripts/config/webpack.config.js

Line 42 in c475dcb

const renderPaths = getRenderPropPaths();

It never gets recalculated in the watch mode, so it doesn't have a chance to detect a new file when processing inside the copy plugin:

https://github.com/WordPress/gutenberg/blob/c475dcb3ffee7627a8e1d2f13f364a7a9b195a61/packages/scripts/config/webpack.config.js#L273L283

[aurooba]

@gziolo That makes sense. I can take a look at this later this week and help fix it. I've been diving into the wp-scripts code to understand it better overall, so I've started to get a good handle on it.

[gziolo]

I can take a look at this later this week and help fix it. I've been diving into the wp-scripts code to understand it better overall, so I've started to get a good handle on it.

Fantastic! 😀

[gziolo]

Fixed with #50939.

[gziolo]

I opened a follow-up #51162 with some performance optimization to the webpack configuration for detecting render PHP files.