tycho-dependency-tools:generate-target doesn't respect mirrors

[Frettman]

I have a working Tycho (5.0.2) build that defines a repository like this:

    <repository>
       <id>myrepo</id>
       <url>jar:https://example.com/p2.zip!/</url>
       <layout>p2</layout>
    </repository>

And I have configured a mirror for it in my settings.xml like this:

    <mirror>
      <id>myrepo-mirror</id>
      <url>jar:file:///X:/p2.zip!/</url>
      <layout>p2</layout>
      <mirrorOf>myrepo</mirrorOf>
      <mirrorOfLayouts>p2</mirrorOfLayouts>
    </mirror>

And I have confirmed that the build works with the mirror and fails without the mirror. However, when running
mvn tycho-dependency-tools:generate-target on the project, the goal fails because it can't access https://example.com/p2.zip, which means that it's not considering the mirror.

[Frettman]

This may be related: When I specify the build target via a target file, the normal Tycho build also does not consider the mirror for the jar:https://example.com/p2.zip!/ URL. When I use https://example.com/p2.zip (which wouldn't work anyway, but for the sake of experimentation) I can see in the console output that it explicitly uses the mirror instead.

[laeubi]

Don't use jar: with p2, this is extremely inefficient because it needs to download the whole jar for every attempt to read a single file from it.

[merks]

Yes, remote zips are horrible! I wonder if you specify https://example.com/p2.zip -> file:///X:/p2.zip for mirroring if that works because only this URI is used to transfer the entire zip file, once per artifact, so redirecting that might well work and will then be not so horrible to use a local jar...

[Frettman]

I wonder if you specify https://example.com/p2.zip -> file:///X:/p2.zip for mirroring if that works because only this URI is used to transfer the entire zip file, once per artifact, so redirecting that might well work and will then be not so horrible to use a local jar...

Just to make sure that I understand you correctly:

The repo URL is still jar:https://example.com/p2.zip!/, but the mirror is configured as:

<mirror>
  <id>myrepo-mirror2</id>
  <url>file:///X:/p2.zip</url>
  <layout>p2</layout>
  <mirrorOf>https://example.com/p2.zip</mirrorOf>
  <mirrorOfLayouts>p2</mirrorOfLayouts>
</mirror>

If that's what you meant: Unfortunately doesn't work; it still fails to access https://example.com/p2.zip.

Even if jar: does weird stuff and shouldn't be used (it also doesn't support credentials), I would have assumed that the whole URL is replaced before someone even tries to resolve it. So it would have weird if that worked.

Anyway, instead of using a mirror, I have the repository URL in a property now. That seems to work so far.