[MRESOLVER-555] Existence check should lax the repository update policy

[jira-importer]

Tamas Cservenak opened MRESOLVER-555 and commented

Maybe only when update policy is "never".

Order of events:

• attempt a build with not-yet-released-artifact (for example resolver in maven)
• as it is not in central, build will fail, and central URL will be "cached" as 404 for given artifact
• fix, rinse, repeat, add staging repository, rebuild
• build will pass ok, as staging repository will have the artifact, it is cached to local repository (from staging repository)
• later, staging repository is dropped, release promoted to central.
• rebuild: here, Resolver will nag that "artifact is present but not available", which is true: it was cached from staging repository
• it will go try to see is it available in central (existence check), but: central has 404 cached (see step 1), and in this case update policy is being obeyed, that is "never"
• due "never" update policy existence check will fail, and build will fail

Now, IMO, for "existence check" Resolver should lax the policy ONLY if it is "never" maybe? As from this situation only escape route is build with -U that will reset local repository state and build will pass.

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Issue Links:

• MNG-8076 when jar in local repository from other repository id, should not reject but check if it is also available in current repository id context

[jira-importer]

Tamas Cservenak commented

This is wrong. This cannot happen in all cases... 

Simply put, Resolver has no notion of "wandering artifacts", but it does try hard to enforce error policy ("cache 404"). 

I think the proper solution would be to be able to assign org.eclipse.aether.resolution.ResolutionErrorPolicy not only session-wide, but to a RemoteRepository (code change in Resolver but also code change in Maven). As then, solution would be:

• super POM states "do not cache 404 for Central", but
• do cache as today (per session level)

Also with this exposed, any organization could set/configure whatever setup they have, like "by the book" setup of staging suite that ends up in releases repo...

Ideas welcome.