Ruby on rails 3.1 rake db：种子导致堆栈级别太深，为什么？

当我尝试运行rake db:seed--trace时，我得到以下错误：

rake aborted!
    stack level too deep

详情如下:

/home/sam/.rvm/rubies/ruby-1.9.3-p0/bin/ruby -e $stdout.sync=true;$stderr.sync=true;load($0=ARGV.shift) /home/sam/.rvm/gems/ruby-1.9.3-p0@dcaclab/bin/rake db:seed --trace
/home/sam/.rvm/gems/ruby-1.9.3-p0@global/gems/rake-0.9.2.2/lib/rake/version.rb:2: warning: already initialized constant VERSION
/home/sam/.rvm/gems/ruby-1.9.3-p0@global/gems/rake-0.9.2.2/lib/rake/version.rb:5: warning: already initialized constant MAJOR
/home/sam/.rvm/gems/ruby-1.9.3-p0@global/gems/rake-0.9.2.2/lib/rake/version.rb:5: warning: already initialized constant MINOR
/home/sam/.rvm/gems/ruby-1.9.3-p0@global/gems/rake-0.9.2.2/lib/rake/version.rb:5: warning: already initialized constant BUILD
/home/sam/.rvm/gems/ruby-1.9.3-p0@global/gems/rake-0.9.2.2/lib/rake/version.rb:5: warning: already initialized constant PATCH
/home/sam/.rvm/gems/ruby-1.9.3-p0@global/gems/rake-0.9.2.2/lib/rake/version.rb:6: warning: already initialized constant NUMBERS
/home/sam/.rvm/gems/ruby-1.9.3-p0@global/gems/rake-0.9.2.2/lib/rake.rb:27: warning: already initialized constant RAKEVERSION
/home/sam/.rvm/gems/ruby-1.9.3-p0@global/gems/rake-0.9.2.2/lib/rake/early_time.rb:17: warning: already initialized constant EARLY
/home/sam/.rvm/gems/ruby-1.9.3-p0@global/gems/rake-0.9.2.2/lib/rake/alt_system.rb:32: warning: already initialized constant WINDOWS
/home/sam/.rvm/gems/ruby-1.9.3-p0@global/gems/rake-0.9.2.2/lib/rake/application.rb:31: warning: already initialized constant DEFAULT_RAKEFILES
WARNING: Possible conflict with Rake extension: String#ext already exists
WARNING: Possible conflict with Rake extension: String#pathmap already exists
/home/sam/.rvm/gems/ruby-1.9.3-p0@global/gems/rake-0.9.2.2/lib/rake/task_arguments.rb:77: warning: already initialized constant EMPTY_TASK_ARGS
/home/sam/.rvm/gems/ruby-1.9.3-p0@global/gems/rake-0.9.2.2/lib/rake/invocation_chain.rb:49: warning: already initialized constant EMPTY
/home/sam/.rvm/gems/ruby-1.9.3-p0@global/gems/rake-0.9.2.2/lib/rake/file_utils.rb:9: warning: already initialized constant RUBY
/home/sam/.rvm/gems/ruby-1.9.3-p0@global/gems/rake-0.9.2.2/lib/rake/file_utils.rb:86: warning: already initialized constant LN_SUPPORTED
/home/sam/.rvm/gems/ruby-1.9.3-p0@global/gems/rake-0.9.2.2/lib/rake/file_utils_ext.rb:16: warning: already initialized constant DEFAULT
/home/sam/.rvm/gems/ruby-1.9.3-p0@global/gems/rake-0.9.2.2/lib/rake/dsl_definition.rb:150: warning: already initialized constant DeprecatedCommands
/home/sam/.rvm/gems/ruby-1.9.3-p0@global/gems/rake-0.9.2.2/lib/rake/file_list.rb:44: warning: already initialized constant ARRAY_METHODS
/home/sam/.rvm/gems/ruby-1.9.3-p0@global/gems/rake-0.9.2.2/lib/rake/file_list.rb:47: warning: already initialized constant MUST_DEFINE
/home/sam/.rvm/gems/ruby-1.9.3-p0@global/gems/rake-0.9.2.2/lib/rake/file_list.rb:51: warning: already initialized constant MUST_NOT_DEFINE
/home/sam/.rvm/gems/ruby-1.9.3-p0@global/gems/rake-0.9.2.2/lib/rake/file_list.rb:55: warning: already initialized constant SPECIAL_RETURN
/home/sam/.rvm/gems/ruby-1.9.3-p0@global/gems/rake-0.9.2.2/lib/rake/file_list.rb:61: warning: already initialized constant DELEGATING_METHODS
/home/sam/.rvm/gems/ruby-1.9.3-p0@global/gems/rake-0.9.2.2/lib/rake/file_list.rb:364: warning: already initialized constant DEFAULT_IGNORE_PATTERNS
/home/sam/.rvm/gems/ruby-1.9.3-p0@global/gems/rake-0.9.2.2/lib/rake/file_list.rb:370: warning: already initialized constant DEFAULT_IGNORE_PROCS
/home/sam/.rvm/gems/ruby-1.9.3-p0@global/gems/rake-0.9.2.2/lib/rake.rb:68: warning: already initialized constant FileList
/home/sam/.rvm/gems/ruby-1.9.3-p0@global/gems/rake-0.9.2.2/lib/rake.rb:69: warning: already initialized constant RakeFileUtils
rake aborted!
stack level too deep
/home/sam/.rvm/gems/ruby-1.9.3-p0@dcaclab/gems/rake-0.9.2.2/lib/rake/rake_module.rb:25

Process finished with exit code 1

---

有什么想法吗？

它可以与空的db/seeds.rb一起工作吗？如果是，请显示该文件。即使种子为空，我也有相同的错误。rb