Failure to download artifact stores & inspects HTTP response code

When an artifact is unable to be downloaded, Maven 3 caches this result for future reference in the "~/.m2/repo/.../<artifact>.lastUpdated" file. For "not found" situations, it seems that the HTTP code could be used to more granularly re-attempt retrieval rather than just cache the failure.

For example, for any 404, I agree, the result should cache the failure and require a -U to attempt to retrieve it again. However, for 400, 500, 501, 502, 503, 301, 302 (what's the Maven behavior for 3xx today?) I think the resolution engine should try to re-retrieve the artifact each time. With those error codes, it seems more likely a config issue or brief network hiccup, not one of the file being absent from that repo. However, that brief network hiccup has longstanding cache implications in that the file is never attempted to be retrieved again.

http://www.w3.org/Protocols/HTTP/HTRESP.html

I've received this feedback from folks trying out Maven 3 Beta 1 and am just trying to aggregate the comments on their behalf.