Exclude URLs that already overlap with defaults

[fregante]

This shouldn't happen with https://github.com/fregante/webext-domain-permission-toggle (untested) but it can happen if the user manually adds permissions.

If manifest.json includes:

{
	"permissions": [
		"https://*.github.com/*",
	]
}

And then the extension calls browser.permissions.request('*://*/*'), neither the browser nor webext-dynamic-content-scripts will deduplicate this with existing permissions, so the scripts will be inserted twice.

[fregante]

I think this can be solved by adding preexisting origins (of each content_script) in the exclude_matches prop

webext-dynamic-content-scripts/index.ts

Lines 23 to 29 in 251bf0c

	const registeredScript = chrome.contentScripts.register({
	js: (config.js || []).map(convertPath),
	css: (config.css || []).map(convertPath),
	allFrames: config.all_frames,
	matches: [origin],
	runAt: config.run_at as browser.extensionTypes.RunAt
	});

Would become:

const registeredScript = chrome.contentScripts.register({
	js: (config.js || []).map(convertPath),
	css: (config.css || []).map(convertPath),
	allFrames: config.all_frames,
	matches: [origin],
+	exclude_matches: config.matches,
	runAt: config.run_at as browser.extensionTypes.RunAt
});

[fregante]

Additionally this should ignore whole scripts that are already enabled on <all_urls> or *://*/*.

The implementation is different since register doesn't need to be called at all, but the concept is the same.

If every script is enabled everywhere, it could use console.warn because this module is useless in that case. A warning rather than an error would be useful for cross-browser extensions. Example: refined-github/refined-github#3766