Support for multicast DNS

[grizeldi]

": can't open git-upload-pack" error after trying to interact with a HTTP remote

Describe the bug
Every time I try to do anything with a HTTP remote (pull, push, fetch...), the operation fails with an error popup, with the text as described in the title. All of the operations work just fine when done from the CLI git. My remote doesn't support HTTPS or SSH, so I couldn't test if any of those works as it should with the same remote.

To Reproduce
Steps to reproduce the behavior:

1. Open a local repository that has a HTTP remote
2. Try any of the operations that interact with the remote (tested with pull and clone)
3. See the error popup

Expected behavior
The operation was supposed to complete as if done via CLI git.

Desktop (please complete the following information):

• OS: Ubuntu 20.04 LTS
• Version 1.0.1 from flathub

[JetpackDuba]

Have you checked for the issues mentioned here? Have you tried with other remotes?

[grizeldi]

I have tried setting the sslVerify to false to no avail. Github remotes seem to work fine.
Another thing that might be worth mentioning is that the remote is using a .local address resolved through mDNS.

[grizeldi]

Update, I tried looking up the remote's IP address and cloning by the actual IP instead of the .local URL seems to work fine. So it's an issue with the way the DNS lookups are done and probably something to do with an upstream library. Should I close this issue?

[JetpackDuba]

That's quite an exotic of a setup. I may try to create a similar setup but not soon, as I want to release 1.1 and I'm quite busy until the end of january.

Can you please run flatpak run com.jetpackduba.Gitnuro and paste the output after getting the error? I may have to somehow tell JGit how to handle such connection, not really sure.

[grizeldi]

Yeah, no worries. I am aware it's a rather exotic setup :)

The relevant part of the output when started from the terminal:

org.eclipse.jgit.api.errors.TransportException: http://carbon.local/user/repo.git: cannot open git-upload-pack
	at org.eclipse.jgit.api.FetchCommand.call(FetchCommand.java:224)
	at org.eclipse.jgit.api.PullCommand.call(PullCommand.java:266)
	at app.git.RemoteOperationsManager$pull$2.invokeSuspend(RemoteOperationsManager.kt:32)
	at app.git.RemoteOperationsManager$pull$2.invoke(RemoteOperationsManager.kt)
	at app.git.RemoteOperationsManager$pull$2.invoke(RemoteOperationsManager.kt)
	at kotlinx.coroutines.intrinsics.UndispatchedKt.startUndispatchedOrReturn(Undispatched.kt:89)
	at kotlinx.coroutines.BuildersKt__Builders_commonKt.withContext(Builders.common.kt:165)
	at kotlinx.coroutines.BuildersKt.withContext(Unknown Source)
	at app.git.RemoteOperationsManager.pull(RemoteOperationsManager.kt:24)
	at app.viewmodels.MenuViewModel$pull$1.invokeSuspend(MenuViewModel.kt:17)
	at app.viewmodels.MenuViewModel$pull$1.invoke(MenuViewModel.kt)
	at app.viewmodels.MenuViewModel$pull$1.invoke(MenuViewModel.kt)
	at app.git.TabState$safeProcessing$1$2.invokeSuspend(TabState.kt:68)
	at app.git.TabState$safeProcessing$1$2.invoke(TabState.kt)
	at app.git.TabState$safeProcessing$1$2.invoke(TabState.kt)
	at app.extensions.StateManagementUtilsKt.delayedStateChange(StateManagementUtils.kt:21)
	at app.git.TabState$safeProcessing$1.invokeSuspend(TabState.kt:62)
	at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt:33)
	at kotlinx.coroutines.DispatchedTask.run(DispatchedTask.kt:106)
	at kotlinx.coroutines.scheduling.CoroutineScheduler.runSafely(CoroutineScheduler.kt:571)
	at kotlinx.coroutines.scheduling.CoroutineScheduler$Worker.executeTask(CoroutineScheduler.kt:750)
	at kotlinx.coroutines.scheduling.CoroutineScheduler$Worker.runWorker(CoroutineScheduler.kt:678)
	at kotlinx.coroutines.scheduling.CoroutineScheduler$Worker.run(CoroutineScheduler.kt:665)
Caused by: org.eclipse.jgit.errors.TransportException: http://carbon.local/user/repo.git: cannot open git-upload-pack
	at org.eclipse.jgit.transport.TransportHttp.connect(TransportHttp.java:749)
	at org.eclipse.jgit.transport.TransportHttp.openFetch(TransportHttp.java:465)
	at org.eclipse.jgit.transport.FetchProcess.executeImp(FetchProcess.java:151)
	at org.eclipse.jgit.transport.FetchProcess.execute(FetchProcess.java:103)
	at org.eclipse.jgit.transport.Transport.fetch(Transport.java:1321)
	at org.eclipse.jgit.api.FetchCommand.call(FetchCommand.java:213)
	... 22 more
Caused by: java.net.UnknownHostException: carbon.local
	at java.base/sun.nio.ch.NioSocketImpl.connect(NioSocketImpl.java:567)
	at java.base/java.net.Socket.connect(Socket.java:633)
	at java.base/sun.net.NetworkClient.doConnect(NetworkClient.java:178)
	at java.base/sun.net.www.http.HttpClient.openServer(HttpClient.java:498)
	at java.base/sun.net.www.http.HttpClient.openServer(HttpClient.java:603)
	at java.base/sun.net.www.http.HttpClient.<init>(HttpClient.java:246)
	at java.base/sun.net.www.http.HttpClient.New(HttpClient.java:351)
	at java.base/sun.net.www.http.HttpClient.New(HttpClient.java:373)
	at java.base/sun.net.www.protocol.http.HttpURLConnection.getNewHttpClient(HttpURLConnection.java:1309)
	at java.base/sun.net.www.protocol.http.HttpURLConnection.plainConnect0(HttpURLConnection.java:1287)
	at java.base/sun.net.www.protocol.http.HttpURLConnection.plainConnect(HttpURLConnection.java:1128)
	at java.base/sun.net.www.protocol.http.HttpURLConnection.connect(HttpURLConnection.java:1057)
	at java.base/sun.net.www.protocol.http.HttpURLConnection.getInputStream0(HttpURLConnection.java:1665)
	at java.base/sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1589)
	at java.base/java.net.HttpURLConnection.getResponseCode(HttpURLConnection.java:529)
	at org.eclipse.jgit.transport.http.JDKHttpConnection.getResponseCode(JDKHttpConnection.java:85)
	at org.eclipse.jgit.util.HttpSupport.response(HttpSupport.java:205)
	at org.eclipse.jgit.transport.TransportHttp.connect(TransportHttp.java:654)
	... 27 more
LastError flow: Error(date=1664748369237, exception=org.eclipse.jgit.api.errors.TransportException: http://carbon.local/user/repo.git: cannot open git-upload-pack, message=http://carbon.local/user/repo.git: cannot open git-upload-pack)

It does indeed seem like the mDNS lookup doesn't work.

[JetpackDuba]

Yeah, after a bit of research I've found that apparently mDNS lookup is not build-in in any Java/Kotlin SDK 😞

I'll have to search for a lib to do it in a future release.

I'll edit the issue as this is a new feature. If using the IP directly is an option, I'd stick with that as a workaround until I can add support for it.

[grizeldi]

The remote I'm using sadly auto redirects to the .local address, so I just went back to CLI git.

If this was a more permanent setup, I'd set up a DNS server, but it's a rather ad hoc setup that will only be used for a week, so I can't be bothered.

[grizeldi]

I'm in a similar situation again and I figured out that as a workaround, manually adding the .local domain into /etc/hosts file makes gitnuro work as intended.

[JetpackDuba]

Sorry for the late response, I completly missed the notification. Thanks for the feedback, I'll add it to the readme.

I've been looking more into it but I don't think there is much I can do aside from documenting your workaround, since it would require diving into JGit internals, something I don't really want to do in case I also use alternative Git libraries such as libgit2 (Not planned for now but it may happen in the future) and it may require a lot of effort for such a particular use case.

I'll close it for now. If someone is willing to implement it in the future, we can reopen it.