OpenID authentication fails to deal with multiple OpenIDs for same email

[hlapp]

When logging in to traitdb-dev with one of my OpenIDs, I get the exception pasted below. This is likely because I probably already have an account, created earlier by logging in with Google.

The bug here is that I get the exception rather than a meaningful suggestion of what I should do instead. The desired enhancement is that the auth system is capable of handling multiple OpenIDs for the same email address. Associating additional OpenIDs to an email may be restricted to having to be logged in already. At the very least, it should be possible to change an associated OpenID to another one.

ActiveRecord::RecordNotUnique in Users::OmniauthCallbacksController#open_id
PG::UniqueViolation: ERROR: duplicate key value violates unique constraint "users_pkey" : INSERT INTO "users" ("created_at", "email", "encrypted_password", "updated_at") VALUES ($1, $2, $3, $4) RETURNING "id"

app/models/user.rb:17:in find_for_open_id' app/controllers/users/omniauth_callbacks_controller.rb:4:inopen_id'

Parameters:

{"openid.response_nonce"=>"2013-12-11T17:54:14ZcMXuEf",
 "openid.ns.sreg"=>"http://openid.net/extensions/sreg/1.1",
 "openid.signed"=>"assoc_handle,
ax.count.ext0,
ax.count.ext1,
ax.count.ext2,
ax.count.ext3,
ax.count.ext4,
ax.count.ext5,
ax.count.ext6,
ax.count.ext7,
ax.count.ext8,
ax.mode,
ax.type.ext0,
ax.type.ext1,
ax.type.ext2,
ax.type.ext3,
ax.type.ext4,
ax.type.ext5,
ax.type.ext6,
ax.type.ext7,
ax.type.ext8,
claimed_id,
identity,
mode,
ns,
ns.ax,
ns.sreg,
op_endpoint,
response_nonce,
return_to,
signed,
sreg.email,
sreg.fullname,
sreg.postcode",
 "openid.sreg.email"=>"[email protected]",
 "openid.op_endpoint"=>"http://www.myopenid.com/server",
 "openid.ax.type.ext8"=>"http://axschema.org/media/image/aspect11",
 "openid.ax.type.ext4"=>"http://axschema.org/namePerson/friendly",
 "openid.ax.type.ext5"=>"http://axschema.org/contact/city/home",
 "openid.identity"=>"http://username.myopenid.com/",
 "openid.ax.type.ext7"=>"http://axschema.org/contact/web/default",
 "openid.ax.type.ext0"=>"http://axschema.org/contact/email",
 "openid.ax.type.ext1"=>"http://axschema.org/namePerson",
 "openid.ax.type.ext2"=>"http://axschema.org/namePerson/first",
 "openid.ax.type.ext3"=>"http://axschema.org/namePerson/last",
 "openid.sig"=>"XXXXXX",
 "openid.return_to"=>"http://traitdb-dev.nescent.org/users/auth/open_id/callback?_method=post",
 "openid.ax.mode"=>"fetch_response",
 "openid.claimed_id"=>"http://username.myopenid.com/",
 "openid.ns.ax"=>"http://openid.net/srv/ax/1.0",
 "openid.mode"=>"id_res",
 "openid.ax.type.ext6"=>"http://axschema.org/contact/state/home",
 "openid.ax.count.ext0"=>"0",
 "openid.ax.count.ext1"=>"0",
 "openid.ax.count.ext2"=>"0",
 "openid.ax.count.ext3"=>"0",
 "openid.ax.count.ext4"=>"0",
 "openid.ax.count.ext5"=>"0",
 "openid.ax.count.ext6"=>"0",
 "openid.ns"=>"http://specs.openid.net/auth/2.0",
 "openid.ax.count.ext8"=>"0",
 "openid.ax.count.ext7"=>"0",
 "openid.sreg.fullname"=>"First Last",
 "openid.sreg.postcode"=>"12345",
 "openid.assoc_handle"=>"{HMAC-SHA1}{XXXXXX}"}