Workspace Templates: show error when fetching templates from Github

[chrisrueger]

In this PR

This PR is about error handling the following two wizards:

This shows an ErrorDialog the UI when there are problems fetching from Github. The error message also includes a hint to https://bnd.bndtools.org/instructions/connection-settings.html because sometimes you have a ~/.m2/settings.xml with some credentials which can lead to "Bad Credentials" http errors from the Github API, but before this fix you had no idea what was going on, because the UI was blank and the existance of ~/.m2/settings.xml is easily forgotten

The message reads (wording improvements welcome):

Failed to load from template loader (Load workspace templates from GitHub repositories) See Error Log for stack trace:
java.io.IOException: Error (HTTP 520) - no response: TaggedData [tag=, code=520, modified=Thu Jan 01 00:59:59 CET
1970, url=https://api.github.com/repos/bndtools/bndtools.workspace.min, state=OTHER] (Check https://bnd.bndtools.org/instructions/connection-settings.html in case of connection or authentication errors.)

Eclipse Error Log tab:

At least now you see that something is wrong and also get some information.
Before this it was completely unknown, since the list of templates just appeared empty.

Last but not least, I added the same ErrorDialog also to the (new) Template Fragment Wizard... which can suffer from the same HTTP connection problems. Now the user sees an error dialog too and knows what's going on

[chrisrueger]

@peterkir could you have a look and see what the output is in your error case with the incorrect credentials in ~/.m2/settings.xml

[chrisrueger]

Build error seems to be because of a http error e.g. when accessing stuff from https://download.eclipse.org/ they seem to have maintanance https://www.eclipsestatus.io/

I will retry later

[peterkir]

Still seeing no error message inside the client when pressing next button on "Setup Bnd Workspace" page.

The empty template is coming

inside the error log the following error message/exception is coming.

2025-01-28 08:44:45,926 [Worker-8: Executing the early startup extensions] INFO  a.b.c.settings.ConnectionSettings - [ConnectionSettings] Read from file: C:\Users\peter\.m2\settings.xml (See https://bnd.bndtools.org/instructions/connection-settings.html for more information)
2025-01-28 08:45:18,679 [HttpClient,https://api.github.com/repos/bndtools/bndtools.workspace.min] INFO  a.bnd.build.LoggingProgressPlugin - Download https://api.github.com/repos/bndtools/bndtools.workspace.min
2025-01-28 08:45:19,206 [Progress Runner] ERROR org.eclipse.equinox.logger - Failed to load from template loader: Load workspace templates from GitHub repositories
org.osgi.util.promise.FailedPromisesException: java.io.IOException: java.lang.NullPointerException: Cannot invoke "java.io.InputStream.available()" because "in" is null
	at org.osgi.util.promise.PromiseFactory$All.run(PromiseFactory.java:362)
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1144)
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:642)
	at java.base/java.lang.Thread.run(Thread.java:1583)
Caused by: java.io.IOException: java.lang.NullPointerException: Cannot invoke "java.io.InputStream.available()" because "in" is null
	at org.bndtools.templating.jgit.Cache.download(Cache.java:58)
	at org.bndtools.templating.jgit.GitHub.lambda$0(GitHub.java:32)
	at org.osgi.util.promise.DeferredPromiseImpl$Submit.run(DeferredPromiseImpl.java:755)
	... 3 common frames omitted
Caused by: java.lang.NullPointerException: Cannot invoke "java.io.InputStream.available()" because "in" is null
	at aQute.lib.io.ByteBufferOutputStream.write(ByteBufferOutputStream.java:77)
	at aQute.lib.io.IO.copy(IO.java:410)
	at aQute.lib.io.IO.read(IO.java:733)
	at org.bndtools.templating.jgit.Cache.download(Cache.java:31)
	... 5 common frames omitted

[chrisrueger]

Caused by: java.io.IOException: java.lang.NullPointerException: Cannot invoke "java.io.InputStream.available()" because "in" is null
	at org.bndtools.templating.jgit.Cache.download(Cache.java:58)

@peterkir I believe you are not using the code of this PR. The line Cache.java:58 in the stacktrace does not do this in this PR:

I actually tried to handle the null inputstream in line 32 and line 50

[peterkir]

[peterkir]

Thx. Error message is highly appreciated