[MNG-8069] add failing projects if a project is banned from reactor

[laeubi]

Currently if a multimodule build fails (either fast or at the end), the user gets a message in the log that reads:

"This project has been banned from the build due to previous failures."

this is correct but does not give a hint what has failed and one needs to investigate the build logs to get more details.

This now instead shows as part of the message the actual project that make it impossible to build this one and is the reason for this project being banned.

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[gnodet]

Wouldn't it be better to add the cause when the project is banned rather than trying to reconstruct it later ? I wonder if we should enhance the blacklist() method to be given a cause...

Also, what about providing two slightly different messages, I think it's interesting to know if the project has been skipped because one project has failed (without the fail-at-end flag, do we actually need to display the failing projects for each skipped project, even unrelated ?) or it's actually an upstream project which caused the failure ?

[laeubi]

The problem is that if you have a multimodule build (lets say 300 modules) and use multithreading (so build messages are interleaved), and one of the projects fail in the middle you have a huge logfile full of "banned" messages but you need to find out what/where it actually fails, so the message without any context is quite useless and even if you find the erroneous project its not very helpful. So I though showing it at tat time might be more useful.

Another approach would be to simply not display the message at all, and instead give a summary at the end of build, e.g.

The following projects where not build due to previous failures:
- a (depends on x that failed)
- b
- c (depends on b that was banned)

sadly currently this information is somehow spread across some places and I'm not sure why e.g. a listener was used instead of printing the message directly on blacklist() ...

regarding fae/ff I think we can add such message of course but I didn't wanted to complicate things for a first draft, if you think its usefull I think it is quite easy to add,

[elharo]

I can't quite follow this comment, please rephrase

[elharo]

are eligible