gem install won't work with multiple sources if one is unavailable

[klauern]

Copied verbatim from issue #29170:

With the Amazon outage, one of the sources I had added outside of rubygems was down (http://rubygems.torquebox.org).
For me, this wasn't a big issue, since it hosts only a few gems that I use and I don't need updated that often. However,
when trying to install a gem or update gems, it would shut down entirely, not being able to find specs.4.8.gz for that
one source. So in effect, gem update was borked because one source wasn't available, regardless of the status of
all others.

Can this just display a warning or something saying something like "can't search ${borked gem server source},
skipping this one" and still try to update, install, etc., from any and all other sources listed?

[jrochkind]

Wonder if this is related to problem I just had, where couldn't install --pre gems until I REMOVED the 'old' gem sources from my default sources. Had to remove the old guys: http://gems.rubyforge.org/ http://gems.rubyonrails.org http://gems.github.com

I gather these are no longer to be used, but one woudln't expect having em in there anyway (along with http://rubygems.org) would prevent installation of gems that are present on http://rubygems.org. But my experience was that ordinarily it did not prevent installation, but it mysteriously DID when trying to install pre-release gem. Wonder if one of those repo's somehow represents as an 'outage' causing behavior noted in this ticket, but somehow only when installing --pre? At any rate, it was certainly confusing to figure out.

[klauern]

I found that if I do the following steps I can reproduce the error on v1.8.5 of Rubygems:

1. gem server on one prompt
2. gem source -a http://localhost:8808 on another prompt
3. gem update same as step 2
4. Ctrl+C the gem server terminal from step 1
5. gem update from terminal on step 2

then you get a nice exception for most gem commands:

$ gem update
Updating installed gems
Updating middleman
ERROR:  While executing gem ... (Gem::DependencyError)
    Unable to resolve dependencies: middleman requires compass (= 0.11.2)

klauer@klauer-iMac ~
$ gem source -r http://localhost:8808
http://localhost:8808 removed from sources

klauer@klauer-iMac ~
$ gem update
Updating installed gems
Updating middleman
Fetching: padrino-core-0.9.29.gem (100%)
...

[klauern]

Now, I was also finding this when running a geminabox server, so I can rule out any confusion about running a gem server locally, too.

[davetron5000]

Confirmed that this is an issue with 1.8.24.

gem sources
*** CURRENT SOURCES ***

http://rubygems.org/
http://geminabox.whatever.net/

geminabox.whatever.net is only available when I'm on my company's VPN, so a ping will know the IP address, presumably from having cached it before, but the host is unreachable until I connect to the VPN

[evanphx]

The error, of erroring out when any source is missing, is fixed. The other issue, of timing out a source, is a separate issue.