[BUG] Install pop-up screen is not working on Brave/Brave Beta/Brave Nightly

[meidoqt]

Problem Description

The install pop-up screen is not appearing when clicking "Install" on Greasyfork, or any other user script site.

I have to copy the user-script .js url, and manually paste it in Link Import for every single script.

Reproduction Steps

1. Use Brave
2. Click "Install" on https://openuserjs.org/scripts/qsniyg/Image_Max_URL, or any other user script.
3. Nothing happens

ScriptCat Version

v1.3.2

Operating System and Browser Information

Windows 11 | Brave 1.92.120 (Official Build) beta (64-bit)

Additional Information (Optional)

No response

[CodFrm]

I was able to reproduce this on Brave with ScriptCat v1.3.2.

The issue does not seem to be caused by the OpenUserJS/GreasyFork page click handler itself. In v1.3.2, ScriptCat relies on a declarativeNetRequest redirect rule to intercept .user.js main-frame requests and redirect them to:

chrome-extension://<extension-id>/src/install.html?url=...

On Brave, the DNR session rules are installed correctly, but the redirect from a downloadable .user.js navigation to the extension install page does not reliably complete. The same kind of DNR rule can redirect to a normal web page, but redirecting to the extension page fails in this flow. As a result, Brave treats the .user.js request as a download/navigation instead of opening ScriptCat’s install screen.

I also verified that chrome.webNavigation.onBeforeNavigate can observe the .user.js navigation in Brave and provides a valid tabId. When using that event to call:

chrome.tabs.update(tabId, { url: chrome.runtime.getURL("src/install.html?url=...") })

the install page opens correctly.

This looks related to the kind of browser-specific behavior we discussed in #1491. I am not saying this is a Chromium-wide restriction, since DNR redirecting to extension pages is still a supported API and #1491 also suggested that the behavior can differ between Chromium-based browsers. But it does show that relying only on DNR redirecting directly to an extension page is fragile in some Chromium forks.

[cyfung1031]

1.8x no issue
1.92 reproducible

macOS.

Chromium Fork issue.

[cyfung1031]

Filed in brave/brave-browser#56457

@CodFrm You can use this skill for similar GitHub issues if there are source code in the external Github repo.
SKILL.md

[cyfung1031]

@CodFrm I think the user base for ScriptCat is large enough. Just let people put pressure on Brave to fix it. Don't always add fixes to ScriptCat to cover external issues.

[LzNOHentai]

Windows
Brave 1.91.175 （正式版本） （64 位）
Chromium: 149.0.7827.155

复现。原来是Brave的问题，不知道那边会不会修了。

[cyfung1031]

@meidoqt @LzNOHentai

I don't want to change ScriptCat in order to fix the Brave-only issue. This is a bug that Brave should fix.
Chrome/Chromium and Helium are not affected.
The Chromium-fork bug due to Enforce webRequestBlocking for non-webview requests

For temporary workaround, install this script in ScriptCat.

// ==UserScript==
// @name         Brave DNR Compatibility Fix for ScriptCat on Chrome 149+
// @namespace    https://docs.scriptcat.org/
// @version      0.1.0
// @description  Works around Brave’s DNR-related extension access restrictions caused by Chrome 149+ enhanced security changes, restoring ScriptCat userscript installation handling.
// @author       ScriptCat
// @match        https://scriptcat.org/*
// @match        https://greasyfork.org/*
// @match        https://sleazyfork.org/*
// @match        https://openuserjs.org/*
// @icon         https://scriptcat.org/favicon.ico
// @grant        GM_openInTab
// @inject-into  content
// ==/UserScript==

(() => {
    "use strict";
    if (
        typeof GM === "undefined" ||
        typeof CSS === "undefined" ||
        typeof browser === "undefined" ||
        GM?.info?.scriptHandler !== "ScriptCat" ||
        !CSS.supports?.("image-rendering: crisp-edges") ||
        typeof mozInnerScreenX === "number" ||
        !GM.info.userAgentData?.brands?.some((e) => +e?.version >= 149)
    ) return;
    // eslint-disable-next-line
    const installPageURL = `chrome-extension://${browser.runtime.id}/src/install.html`;
    const handler = (event) => {
        event.preventDefault();
        event.stopImmediatePropagation();
        event.stopPropagation();
        GM_openInTab(`${installPageURL}?url=${event.currentTarget.href}`);
    };
    new MutationObserver(() => {
        for (const link of document.querySelectorAll('a[href$=".user.js"]:not([brave-issue-56457])')) {
            link.setAttribute("brave-issue-56457", "");
            link.addEventListener("click", handler, true);
        }
    }).observe(document.documentElement, {
        childList: true,
        subtree: true
    });
})();