[XDebug Bridge] Fetch all array keys when inspecting an array

[adamziel]

Motivation for the change, related issues

Fixes two problems:

• Fetches all the array keys when inspecting arrays. property_get XDebug command is paginated and before this PR, we'd only see a subset of all the array keys. With this PR, we see all the keys. This will be a problem on huge arrays so we'll need to bucket keys into group of 1000 in a follow-up PR.
• Supports actually browsing superglobals, e.g. $_SERVER. Before this PR, you'd only see another nested superglobal (see the screenshot below).

As for the latter, I'm not too happy about the solution – we're reaching for the nested XDebug .property.property when it's available. I expect that will lead us astray in some scenarios, e.g. when browsing arrays that have nested arrays. That being said, I couldn't easily break it so let's get it in and continue iterating:

const responseProps =
	response.property?.property ?? response.property;

Testing instructions

Run nx run php-wasm-cli:dev --xdebug --devtools xdebug.php before and after this PR. Confirm you see the following results:

Before

After ($_SERVER is still duplicated – let's fix that separately)

[mho22]

I think I found a way to avoid having that duplicate array inside itself. When paginating, the last element is the element itself with :

{
  '$': {
    name: '$_ENV',
    fullname: '$_ENV',
    type: 'array',
    children: '1',
    numchildren: '86',
    page: '3',
    pagesize: '32'
  }
}

So instead of injecting the object itself again in the array, let's check if the current page is actually '0' and add it. Do nothing otherwise.

xdebug-cdp-bridge.ts on line 795

	// Use same depth/context as parent
	this.objectHandles.set(childObjectId, {
		type: 'property',
		depth: depth,
		contextId: contextId,
		fullname: prop.$.fullname || name,
	});

+	if (prop.$.page == 0) {
		currentProps.push({
			name: prop.$.key || name,
			value: {
				type: 'object',
				className: className,
				description: className,
				objectId: childObjectId,
			},
			writable: false,
			configurable: false,
			enumerable: true,
		});
+	}
} else { 

[mho22]

@adamziel would you like me to take over this pull request?

[adamziel]

@mho22 yes please, thank you!

[mho22]

I think your solution is great :

const responseProps =
	response.property?.property ?? response.property;

Based on my findings in a previous comment, it seems like the last element of an array is the array itself without its property property. I will try to find a nested array example to be sure it works as expected.

I will also try to add multiple tests to cover what has been added in this pull request.