[Bug] Unable to access redirected JSON Schema URL

Reproducible in vscode.dev or in VS Code Desktop?

• Not reproducible in vscode.dev or VS Code Desktop

Reproducible in the monaco editor playground?

• Not reproducible in the monaco editor playground

Monaco Editor Playground Link

No response

Monaco Editor Playground Code

var jsonCode = [
	"{",
	'    "$schema": "https://schemas.wp.org/trunk/theme.json",',
	"}"
].join("\n");
var modelUri = monaco.Uri.parse("a://b/foo.json"); // a made up unique URI for our model
var model = monaco.editor.createModel(jsonCode, "json", modelUri);

monaco.languages.json.jsonDefaults.setDiagnosticsOptions( {
	validate: true,
	allowComments: false,
	enableSchemaRequest: true,
} );

monaco.editor.create(document.getElementById("container"), {
	model: model,
});

Reproduction Steps

• Switch Example in Monaco Editor Playground to "Configure Json Defaults".
• Paste the code.

Actual (Problematic) Behavior

Editor says "Unable to load schema from 'https://schemas.wp.org/trunk/theme.json': Failed to fetch."

Expected Behavior

Read the JSON Schema URL and validation should work.

Additional Context

This may not be a bug, but it seems like it's not correctly reading JSON Schema URLs with 301 redirects applied.

The schema URL I tested is https://schemas.wp.org/trunk/theme.json, which redirects to https://raw.githubusercontent.com/WordPress/gutenberg/trunk/schemas/json/theme.json.

You can check the redirect trace results with https://wheregoes.com/trace/2024102008/.

• The same problem can be reproduced with vscode.dev.
• Works correctly in VS Code Desktop

❌ URL before being redirected

✅ URL after being redirected

Start with the Configure Json Defaults playground example and the JSON diagnostics path enabled by enableSchemaRequest. Reproduce the failure with the schemas.wp.org URL, compare it with the redirected raw.githubusercontent.com URL, and verify that the original URL loads and validation works after the fix.