When deleting a user with associated roles, a PG::NotNullViolation is logged.

Started DELETE "/users/5-manager" for 127.0.0.1 at 2014-03-12 11:14:16 +0000
Processing by UsersController#destroy as HTML
  Parameters: {"authenticity_token"=>"wzjXWaEKXmEYUJ6ROjqfRjWmyUJzUzbcnppgD9PtJ90=", "id"=>"5-manager"}
  User Load (1.0ms)  SELECT "users".* FROM "users" WHERE "users"."id" = $1 LIMIT 1  [["id", 1]]
Setting current user thread-local variable to admin
  User Load (0.5ms)  SELECT "users".* FROM "users" WHERE "users"."id" = $1 ORDER BY firstname LIMIT 1  [["id", "5-manager"]]
   (0.2ms)  BEGIN
  TaxableTaxonomy Load (0.4ms)  SELECT "taxable_taxonomies".* FROM "taxable_taxonomies" WHERE "taxable_taxonomies"."taxable_id" = 5 AND "taxable_taxonomies"."taxable_type" = 'User'
  CACHE (0.0ms)  SELECT "taxable_taxonomies".* FROM "taxable_taxonomies" WHERE "taxable_taxonomies"."taxable_id" = 5 AND "taxable_taxonomies"."taxable_type" = 'User'
  User Load (0.6ms)  SELECT "users".* FROM "users" WHERE "users"."id" = 5 ORDER BY firstname LIMIT 1
   (0.5ms)  SELECT MAX("audits"."version") AS max_id FROM "audits" WHERE "audits"."auditable_id" = 5 AND "audits"."auditable_type" = 'User'
  SQL (1.4ms)  INSERT INTO "audits" ("action", "associated_id", "associated_name", "associated_type", "auditable_id", "auditable_name", "auditable_type", "audited_changes", "comment", "created_at", "remote_address", "user_id", "user_type", "username", "version") VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11, $12, $13, $14, $15) RETURNING "id"  [["action", "destroy"], ["associated_id", nil], ["associated_name", nil], ["associated_type", nil], ["auditable_id", 5], ["auditable_name", "Manager "], ["auditable_type", "User"], ["audited_changes", "---\nlogin: manager\nfirstname: Manager\nlastname: ''\nmail: manager@localhost\nadmin: false\nauth_source_id: 1\ndomains_andor: or\nhostgroups_andor: or\nfacts_andor: or\nfilter_on_owner: false\ncompute_resources_andor: or\norganizations_andor: or\nlocations_andor: or\nsubscribe_to_all_hostgroups: \nlocale: \navatar_hash: \n"], ["comment", nil], ["created_at", Wed, 12 Mar 2014 11:14:16 UTC +00:00], ["remote_address", "127.0.0.1"], ["user_id", nil], ["user_type", nil], ["username", "Admin User"], ["version", 2]]
  Host::Managed Load (1.1ms)  SELECT "hosts".* FROM "hosts" WHERE "hosts"."type" IN ('Host::Managed') AND "hosts"."owner_id" = 5 AND "hosts"."owner_type" = 'User'
  Hostgroup Load (1.4ms)  SELECT "hostgroups".* FROM "hostgroups" INNER JOIN "user_hostgroups" ON "hostgroups"."id" = "user_hostgroups"."hostgroup_id" WHERE "user_hostgroups"."user_id" = 5 ORDER BY hostgroups.title
  UsergroupMember Load (0.3ms)  SELECT "usergroup_members".* FROM "usergroup_members" WHERE "usergroup_members"."member_id" = 5 AND "usergroup_members"."member_type" = 'User'
  UserRole Load (0.2ms)  SELECT "user_roles".* FROM "user_roles" WHERE "user_roles"."owner_id" = 5 AND "user_roles"."owner_type" = 'User'
  CachedUserRole Load (0.3ms)  SELECT "cached_user_roles".* FROM "cached_user_roles" WHERE "cached_user_roles"."user_role_id" = 61
  SQL (0.6ms)  DELETE FROM "cached_user_roles" WHERE "cached_user_roles"."id" = $1  [["id", 21]]
  SQL (0.4ms)  DELETE FROM "user_roles" WHERE "user_roles"."id" = $1  [["id", 61]]
  CachedUserRole Load (0.3ms)  SELECT "cached_user_roles".* FROM "cached_user_roles" WHERE "cached_user_roles"."user_role_id" = 63
  SQL (0.2ms)  DELETE FROM "cached_user_roles" WHERE "cached_user_roles"."id" = $1  [["id", 22]]
  SQL (0.2ms)  DELETE FROM "user_roles" WHERE "user_roles"."id" = $1  [["id", 63]]
  CachedUserRole Load (0.3ms)  SELECT "cached_user_roles".* FROM "cached_user_roles" WHERE "cached_user_roles"."user_role_id" = 64
  SQL (0.2ms)  DELETE FROM "cached_user_roles" WHERE "cached_user_roles"."id" = $1  [["id", 23]]
  SQL (0.2ms)  DELETE FROM "user_roles" WHERE "user_roles"."id" = $1  [["id", 64]]
  Role Load (0.4ms)  SELECT "roles".* FROM "roles" INNER JOIN "user_roles" ON "roles"."id" = "user_roles"."role_id" WHERE "user_roles"."owner_id" = 5 AND "user_roles"."owner_type" = 'User'
  CachedUserRole Load (0.4ms)  SELECT "cached_user_roles".* FROM "cached_user_roles" WHERE "cached_user_roles"."user_id" = 5
  UserHostgroup Load (0.3ms)  SELECT "user_hostgroups".* FROM "user_hostgroups" WHERE "user_hostgroups"."user_id" = 5
  UserFact Load (0.3ms)  SELECT "user_facts".* FROM "user_facts" WHERE "user_facts"."user_id" = 5
  Domain Load (0.4ms)  SELECT "domains".* FROM "domains" INNER JOIN "user_domains" ON "domains"."id" = "user_domains"."domain_id" WHERE "user_domains"."user_id" = 5 ORDER BY domains.name
  ComputeResource Load (0.4ms)  SELECT "compute_resources".* FROM "compute_resources" INNER JOIN "user_compute_resources" ON "compute_resources"."id" = "user_compute_resources"."compute_resource_id" WHERE "user_compute_resources"."user_id" = 5 ORDER BY compute_resources.name
  Notice Load (0.4ms)  SELECT "notices".* FROM "notices" INNER JOIN "user_notices" ON "notices"."id" = "user_notices"."notice_id" WHERE "user_notices"."user_id" = 5
  SQL (1.2ms)  DELETE FROM "users" WHERE "users"."id" = $1  [["id", 5]]
   (4.4ms)  COMMIT
  Role Load (0.4ms)  SELECT "roles".* FROM "roles" WHERE "roles"."name" = 'Anonymous' LIMIT 1
   (0.1ms)  BEGIN
  UserRole Exists (0.4ms)  SELECT 1 AS one FROM "user_roles" WHERE ("user_roles"."owner_id" = 5 AND "user_roles"."role_id" = 8 AND "user_roles"."owner_type" = 'User') LIMIT 1
  SQL (0.8ms)  INSERT INTO "user_roles" ("owner_id", "owner_type", "role_id") VALUES ($1, $2, $3) RETURNING "id"  [["owner_id", 5], ["owner_type", "User"], ["role_id", 8]]
  User Load (0.9ms)  SELECT "users".* FROM "users" WHERE "users"."id" = 5 ORDER BY firstname LIMIT 1
  SQL (1.2ms)  INSERT INTO "cached_user_roles" ("created_at", "role_id", "updated_at", "user_id", "user_role_id") VALUES ($1, $2, $3, $4, $5) RETURNING "id"  [["created_at", Wed, 12 Mar 2014 11:14:16 UTC +00:00], ["role_id", 8], ["updated_at", Wed, 12 Mar 2014 11:14:16 UTC +00:00], ["user_id", nil], ["user_role_id", 91]]
PG::NotNullViolation: ERROR:  null value in column "user_id" violates not-null constraint
: INSERT INTO "cached_user_roles" ("created_at", "role_id", "updated_at", "user_id", "user_role_id") VALUES ($1, $2, $3, $4, $5) RETURNING "id" 
   (0.1ms)  ROLLBACK
PG::NotNullViolation: ERROR:  null value in column "user_id" violates not-null constraint
: INSERT INTO "cached_user_roles" ("created_at", "role_id", "updated_at", "user_id", "user_role_id") VALUES ($1, $2, $3, $4, $5) RETURNING "id" 
Redirected to http://0.0.0.0:3000/users
Completed 302 Found in 354.6ms (ActiveRecord: 38.0ms)

(https://bugzilla.redhat.com/show_bug.cgi?id=1075550)