fix(core): sync windows metadata across all windows, closes #5571

[amrbashir]

What kind of change does this PR introduce?

• Bugfix
• Feature
• Docs
• New Binding issue #___
• Code style update
• Refactor
• Build-related changes
• Other, please describe:

Does this PR introduce a breaking change?

• Yes, and the changes were approved in issue #___
• No

Checklist

• When resolving issues, they are referenced in the PR's title (e.g fix: remove a typo, closes #___, #___)
• A change file is added if any packages will require a version bump due to this PR per the instructions in the readme.
• I have added a convincing reason for adding this feature, if necessary

Other information

[FabianLars]

Tested on Windows.

[lucasfernog]

Unfortunately this does not fix the sync issue completely. The main issue is that we use an initialization script to set the windows metadata (the init script is static and the metadata is dynamic). I started working on a fix for this when the issue was raised, I'll check if it doesn't introduce a breaking change (last time I thought it would).

An easy way to test is run the API example, create a second window, close the main window, and then reload the page of the second window. The metadata will contain the main label.

[lucasfernog]

Ahh I remembered why I didn't finish my own work, it uses the custom protocol to inject the metadata so it needs the dev server proxy to work on dev :(

[lucasfernog]

Let's try this solution for now then :(

[FabianLars]

Disabling page reloads is a common request anyway :D

Can't we use the normal IPC instead of a custom protocol?

[lucasfernog]

We can but if we use it, there'll be a small delay where you'll see a wrong list of labels.

[lucasfernog]

Works on Windows, but it doesn't work on Linux. It seems like the first eval() call is lost on Linux, probably because the window isn't loaded yet. (i'll merge this anyway if we can't figure it out, it might be some webkit2gtk race condition).

[lucasfernog]

Ok it gives me this error: Err(Error { domain: WebKitJavascriptError, code: 699, message: "undefined:1:40: TypeError: undefined is not an object (evaluating 'window.__TAURI_METADATA__.__windows = [\"A\",\"B\"].map(function (label) { return { label: label } })')" }).

It makes sense, but if I change the script to set window.x = 5, the variable isn't there when the app loads.

[lucasfernog]

I'll push a possible wry fix and let the wry gods decide.

[lucasfernog]

Aaand I had to do the same on macOS. Maybe this is more workarounds than we should have? cc @amrbashir @wusyong (see tauri-apps/wry#815).

[amrbashir]

I think it is fine to queue the eval() scripts until the page loads as most users will expect full access to the window object.