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WorldWideTelescope / wwt-windows-client

WorldWide Telescope Windows Application
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Possible caching bug in UWP build #150

Closed pkgw closed 4 years ago

pkgw commented 4 years ago

I've been checking out the Windows client codebase to understand the web calls that it makes since it would be pretty bad to break those as I work on the web infrastructure! I noticed something that worries me.

When the Windows client logs in, it does the update checks and gets the data version from the server. If the data version has changed, it sets DataSetManager.DataFresh = False.

From what I see, that variable is only used in in DataSetManager.DownloadFile(), so that seems to be the core routine where the Windows client decides that it needs to refresh its data.

But the DataFresh flag is only referenced on the #if !WINDOWS_UWP branch of the code (line 149). On the WINDOWS_UWP side, it seems to unconditionally download the file, with a try/catch that looks like it will fire if the file exists. The DataFresh flag isn't referenced.

So my worry is that, if I'm understanding the pieces correctly, UWP clients won't update their data caches when told to by the server, because as far as I can tell that information is only propagated through the DataFresh flag.

astrojonathan commented 4 years ago

UWP client does not do much caching, it acts more like the web client and downloads files ignoring fresh state. We don't ship any "built" projects yet on UWP, it is experimental in nature right now, so its not impacting end users.

pkgw commented 4 years ago

OK that is good to know. I had misunderstood the broad context and had thought that the 6.0 Windows client was UWP based, so I was worried that this issue would have a much bigger impact.

philrosenfield commented 4 years ago

Can this be closed?

pkgw commented 4 years ago

Looks like there's a potential issue here, but unlikely to cause problems in practice — I'll go ahead and close it.