I've seen similar questions regarding this error, but all of them rails-related. I'm not using rails; I'm working on a local rake task that reads from a yaml file and then does stuff with the data. I'd rather not install bundler for this (the solutions for the similar rails issues suggest prepending with bundle exec), since this script is simple and thus shouldn't need it.
Here's the simplified code, (which gets the same error as the code I'm working on):
require 'FileUtils'
require 'yaml'
SOME_FILE = "#{Dir.pwd}/some_file.yaml"
task default: :foo
task :foo do
bar = File.open(SOME_FILE) { |yf| YAML::load( yf ) }
bar.each {|k,v| puts k}
end
And here's the list of errors:
/Users/jpalmieri/.rbenv/versions/2.0.0-p353/lib/ruby/2.0.0/FileUtils.rb:93: warning: already initialized constant FileUtils::OPT_TABLE
/Users/jpalmieri/.rbenv/versions/2.0.0-p353/lib/ruby/2.0.0/fileutils.rb:93: warning: previous definition of OPT_TABLE was here
/Users/jpalmieri/.rbenv/versions/2.0.0-p353/lib/ruby/2.0.0/FileUtils.rb:1272: warning: already initialized constant FileUtils::Entry_::S_IF_DOOR
/Users/jpalmieri/.rbenv/versions/2.0.0-p353/lib/ruby/2.0.0/fileutils.rb:1272: warning: previous definition of S_IF_DOOR was here
/Users/jpalmieri/.rbenv/versions/2.0.0-p353/lib/ruby/2.0.0/FileUtils.rb:1535: warning: already initialized constant FileUtils::Entry_::DIRECTORY_TERM
/Users/jpalmieri/.rbenv/versions/2.0.0-p353/lib/ruby/2.0.0/fileutils.rb:1535: warning: previous definition of DIRECTORY_TERM was here
/Users/jpalmieri/.rbenv/versions/2.0.0-p353/lib/ruby/2.0.0/FileUtils.rb:1537: warning: already initialized constant FileUtils::Entry_::SYSCASE
/Users/jpalmieri/.rbenv/versions/2.0.0-p353/lib/ruby/2.0.0/fileutils.rb:1537: warning: previous definition of SYSCASE was here
/Users/jpalmieri/.rbenv/versions/2.0.0-p353/lib/ruby/2.0.0/FileUtils.rb:1656: warning: already initialized constant FileUtils::LOW_METHODS
/Users/jpalmieri/.rbenv/versions/2.0.0-p353/lib/ruby/2.0.0/fileutils.rb:1656: warning: previous definition of LOW_METHODS was here
/Users/jpalmieri/.rbenv/versions/2.0.0-p353/lib/ruby/2.0.0/FileUtils.rb:1662: warning: already initialized constant FileUtils::METHODS
/Users/jpalmieri/.rbenv/versions/2.0.0-p353/lib/ruby/2.0.0/fileutils.rb:1662: warning: previous definition of METHODS was here
The script will run fine despite the warnings; the above code would puts the keys as expected, right after the warnings.
This warning shows up when I write require 'FileUtils'. If I write require 'fileutils' (all lower case) warning disappears.
This link may be helpful explaining the behavior. I think in essence ruby thinks FileUtils and fileutils are different modules, therefore imports it twice. Then the redeclaration of constants give warning messages.
Wanted to answer this clearly (two years after it was asked) in case anyone wanders in here.
First, note that require in Ruby does not load a Module, as in the object FileUtils that is in memory. It loads the file "fileutils.rb" from your hard drive. The ".rb" is omitted by convention but you could write require 'fileutils.rb'.
The purpose of require in Ruby is to load a file only once, as opposed to load which will reload the file every time it is used. The way require avoids loading a file multiple times is by recording the filename argument and skipping it if it if that filename is passed again.
When you first require a file, Ruby responds with true to indicate that it was loaded. If you require the same file again it will return false to indicate that it was already loaded:
> require 'fileutils'
=> true
> require 'fileutils'
=> false
Since the filename stored by require is case-sensitive, but the actual file lookup is not, fileutils.rb will still be found if you use caps in the name:
> require 'FileUtils'
=> true
But if something in your Ruby program already loaded that file without caps (in your case "yaml.rb" probably requires "fileutils" as well) you will reload the file and may see warnings:
> require 'fileutils'
=> true
> require 'FileUtils'
/bin/ruby/lib/ruby/2.3.0/FileUtils.rb:96: warning: already initialized constant FileUtils::OPT_TABLE
etc.
By convention Ruby files should be named in lowercase with underscores, e.g. "my_class.rb", so you would always use require 'my_class'.
Things get a little trickier if you are requiring using absolute or relative paths, e.g. require 'special_classes/my_class'. I suggest reading about require_relative and the Ruby load path ($LOAD_PATH).
I solved this similar issue when I list my gem items which named "fileutils" has two versions
fileutils (1.1.0, default: 1.0.2)
then I run
sudo gem uninstall fileutils -v 1.1.0
and solved
I found that these warnings don't appear and the script runs perfectly if I simply comment out or remove line 1 of my original code (require 'FileUtils'). Although I haven't browsed the code for Rake, it must already include FileUtils (which makes sense).
For the sake of completeness, here is my revised code (note that I removed the require 'FileUtils' line:
require 'yaml'
SOME_FILE = "#{Dir.pwd}/some_file.yaml"
task default: :foo
task :foo do
bar = File.open(SOME_FILE) { |yf| YAML::load( yf ) }
bar.each {|k,v| puts k}
end
I was having the same issue with Travis and the problem was that I forgot to use bundle exec rake db:setup instead of rake db:setup. Hope it helps someone :)
Related
What is the difference between require_relative and require in Ruby?
Just look at the docs:
require_relative complements the builtin method require by allowing you to load a file that is relative to the file containing the require_relative statement.
For example, if you have unit test classes in the "test" directory, and data for them under the test "test/data" directory, then you might use a line like this in a test case:
require_relative "data/customer_data_1"
require_relative is a convenient subset of require
require_relative('path')
equals:
require(File.expand_path('path', File.dirname(__FILE__)))
if __FILE__ is defined, or it raises LoadError otherwise.
This implies that:
require_relative 'a' and require_relative './a' require relative to the current file (__FILE__).
This is what you want to use when requiring inside your library, since you don't want the result to depend on the current directory of the caller.
eval('require_relative("a.rb")') raises LoadError because __FILE__ is not defined inside eval.
This is why you can't use require_relative in RSpec tests, which get evaled.
The following operations are only possible with require:
require './a.rb' requires relative to the current directory
require 'a.rb' uses the search path ($LOAD_PATH) to require. It does not find files relative to current directory or path.
This is not possible with require_relative because the docs say that path search only happens when "the filename does not resolve to an absolute path" (i.e. starts with / or ./ or ../), which is always the case for File.expand_path.
The following operation is possible with both, but you will want to use require as it is shorter and more efficient:
require '/a.rb' and require_relative '/a.rb' both require the absolute path.
Reading the source
When the docs are not clear, I recommend that you take a look at the sources (toggle source in the docs). In some cases, it helps to understand what is going on.
require:
VALUE rb_f_require(VALUE obj, VALUE fname) {
return rb_require_safe(fname, rb_safe_level());
}
require_relative:
VALUE rb_f_require_relative(VALUE obj, VALUE fname) {
VALUE base = rb_current_realfilepath();
if (NIL_P(base)) {
rb_loaderror("cannot infer basepath");
}
base = rb_file_dirname(base);
return rb_require_safe(rb_file_absolute_path(fname, base), rb_safe_level());
}
This allows us to conclude that
require_relative('path')
is the same as:
require(File.expand_path('path', File.dirname(__FILE__)))
because:
rb_file_absolute_path =~ File.expand_path
rb_file_dirname1 =~ File.dirname
rb_current_realfilepath =~ __FILE__
Summary
Use require for installed gems
Use require_relative for local files
require uses your $LOAD_PATH to find the files.
require_relative uses the current location of the file using the statement
require
Require relies on you having installed (e.g. gem install [package]) a package somewhere on your system for that functionality.
When using require you can use the "./" format for a file in the current directory, e.g. require "./my_file" but that is not a common or recommended practice and you should use require_relative instead.
require_relative
This simply means include the file 'relative to the location of the file with the require_relative statement'. I generally recommend that files should be "within" the current directory tree as opposed to "up", e.g. don't use
require_relative '../../../filename'
(up 3 directory levels) within the file system because that tends to create unnecessary and brittle dependencies. However in some cases if you are already 'deep' within a directory tree then "up and down" another directory tree branch may be necessary. More simply perhaps, don't use require_relative for files outside of this repository (assuming you are using git which is largely a de-facto standard at this point, late 2018).
Note that require_relative uses the current directory of the file with the require_relative statement (so not necessarily your current directory that you are using the command from). This keeps the require_relative path "stable" as it always be relative to the file requiring it in the same way.
From Ruby API:
require_relative complements the
builtin method require by allowing you
to load a file that is relative to the
file containing the require_relative
statement.
When you use require to load a file,
you are usually accessing
functionality that has been properly
installed, and made accessible, in
your system. require does not offer a
good solution for loading files within
the project’s code. This may be useful
during a development phase, for
accessing test data, or even for
accessing files that are "locked" away
inside a project, not intended for
outside use.
For example, if you have unit test
classes in the "test" directory, and
data for them under the test
"test/data" directory, then you might
use a line like this in a test case:
require_relative "data/customer_data_1"
Since neither
"test" nor "test/data" are likely to
be in Ruby’s library path (and for
good reason), a normal require won’t
find them. require_relative is a good
solution for this particular problem.
You may include or omit the extension
(.rb or .so) of the file you are
loading.
path must respond to to_str.
You can find the documentation at http://extensions.rubyforge.org/rdoc/classes/Kernel.html
The top answers are correct, but deeply technical. For those newer to Ruby:
require_relative will most likely be used to bring in code from another file that you wrote.
for example, what if you have data in ~/my-project/data.rb and you want to include that in ~/my-project/solution.rb? in solution.rb you would add require_relative 'data'.
it is important to note these files do not need to be in the same directory. require_relative '../../folder1/folder2/data' is also valid.
require will most likely be used to bring in code from a library someone else wrote.
for example, what if you want to use one of the helper functions provided in the active_support library? you'll need to install the gem with gem install activesupport and then in the file require 'active_support'.
require 'active_support/all'
"FooBar".underscore
Said differently--
require_relative requires a file specifically pointed to relative to the file that calls it.
require requires a file included in the $LOAD_PATH.
I just saw the RSpec's code has some comment on require_relative being O(1) constant and require being O(N) linear. So probably the difference is that require_relative is the preferred one than require.
I want to add that when using Windows you can use require './1.rb' if the script is run local or from a mapped network drive but when run from an UNC \\servername\sharename\folder path you need to use require_relative './1.rb'.
I don't mingle in the discussion which to use for other reasons.
absolute path
require './app/example_file.rb'
shortened name
require_relative 'example_file'
I'm building a Ruby gem that includes a module that's meant to monkey-patch the Hash class to add a new method. I'm following this guide to try to do it neatly: http://www.justinweiss.com/articles/3-ways-to-monkey-patch-without-making-a-mess/
I've placed the module in lib/core_extensions/hash/prune.rb, and the module is declared as such:
module CoreExtensions
module Hash
module Prune
##
# Removes all pairs from the Hash for which the value is nil. Destructive!
def prune!
self.reject! { |_, v| v.nil? }
end
end
end
end
And in order to make the monkey patch take effect, I'm calling this within the main gem file:
Hash.include(CoreExtensions::Hash::Prune)
But after building the gem and trying to require it in an irb console, I get the following error: NameError: uninitialized constant Gem::CoreExtensions (Gem is a placeholder name).
I made sure to include the prune.rb file in my gemspec's files array: s.files = ['lib/gem.rb', 'lib/core_extensions/hash/prune.rb'], so I'm not sure why it can't detect the file and its modules. Can anyone help me figure this out?
Thank you!
EDIT: In case it will help anyone else - I tried to require the module file using require 'lib/core_extensions/hash/prune' but received 'cannot load such file' errors. Sticking ./ in front of the path fixed it.
I want to write spec for my rubocop custom cop. This gem has handy helpers defined here. I want to require it. How to achieve what?
I've tried to use Gem.find_files, and this gives me ability to require any file in that gem, but only under lib directory.
For example:
# this requires ...gems/rubocop-0.29.1/lib/rubocop/formatter/formatter_set.rb
require Gem.find_files('rubocop/formatter/formatter_set.rb').first
# but I need ...gems/rubocop-0.29.1/spec/support/cop_helper.rb
The following describes why I need it. I have spec/rubocop/my_custom_cop_spec.rb
require 'spec_helper'
require ? # What I should I write?
RSpec.describe RuboCop::Cop::Style::MyCustomCop do
it 'some test' do
inspect_source(cop, 'method(arg1, arg2)') # This helper I want to use from rubocop spec helpers
end
end
When I try plain require:
require 'rubocop/spec/support/cop_helper'
I receive error:
/home/user/.gem/ruby/2.0.0/gems/activesupport-4.2.0/lib/active_support/dependencies.rb:274
:in `require': cannot load such file -- rubocop/spec/support/cop_helper
I found a solution that I think is a little more syntactically elegant:
gem_dir = Gem::Specification.find_by_name("my_gem").gem_dir
require "#{gem_dir}/spec"
I was so blinded, I already have path to file and able to get relative from it.
require 'pathname'
rubocop_path = Pathname.new(Gem.find_files('rubocop.rb').first).dirname
rubocop_path # => ...gems/rubocop-0.29.1/lib
require "#{rubocop_path}/../spec/support/cop_helper.rb"
You can see everything in the file structure at github.com/ddd1600/simple_angel
I'm getting alot of errors while trying to create a ruby application (soon to be a gem) "the correct way", viz. by thoroughly dividing the logic into classes and "loader files" and all of that. Point is, I know how to do this code the simpler way, without obeying OO principles, but I want to do it "correctly".
So, first of all, the file structure is as follows---
root folder = ~/Develop/simple_angel
inside /simple_angel
- /lib
- Gemfile
- Rakefile
- simple_angel.gemspec
inside /lib
- simple_angel.rb
- /simple_angel
inside /lib/simple_angel
- company.rb
- search.rb
- version.rb
But, here are some basics.
Here is what I'm calling to run this program from the terminal (PATH when running is ~/Develop/simple_angel)
ruby -Ilib lib/simple_angel/search.rb
Here is search.rb
#these 'requires' are supposed to be loaded in lib/simple_angel.rb, so here I show
#them commented out
#
#require 'rubygems'
#require 'httparty'
#require 'json'
#require 'company'
module SimpleAngel
class Search
SEARCH_URL = "http://api.angel.co/1/startups"
def search(user_input)
response = HTTParty.get("#{SEARCH_URL}/#{user_input}")
parsed_response = JSON.parse(response.body)
Company.new(parsed_response)
end
end
s = SimpleAngel::Search.new
s = Search.new
x = s.search(6702)
p x
end
Here is the "loader" file, lib/simple_angel.rb (PS: what is a more formal title for this sort of file?)
require 'httparty'
require 'json'
require 'simple_angel/search'
require 'simple_angel/version'
require 'simple_angel/company'
module SimpleAngel
end
Lastly, when I (again), run "ruby -Ilib lib/simple_angel/search.rb" (with all of search.rb's 'requires' commented out (^&^), this is my error message:
[ddouglas#coders:~/Develop/simple_angel on master]
% ruby -Ilib lib/simple_angel/search.rb
lib/simple_angel/search.rb:15:in `search': uninitialized constant SimpleAngel::Search::HTTParty (NameError)
from lib/simple_angel/search.rb:24:in `<module:SimpleAngel>'
from lib/simple_angel/search.rb:8:in `<main>'
^&^ - now that we're all up to speed here, I might as well include the error that happened when I left search.rb's "requires" in place
% ruby -Ilib lib/simple_angel/search.rb ✹
/usr/lib/ruby/1.9.1/rubygems/custom_require.rb:36:in `require': cannot load such file -- company (LoadError)
from /usr/lib/ruby/1.9.1/rubygems/custom_require.rb:36:in `require'
from lib/simple_angel/search.rb:6:in `<main>'
I can't say I understand the point the class is trying to make regarding splitting up your files.
The first error (uninitialized constant SimpleAngel::Search::HTTParty) is because from within SimpleAngel::Search, you call HTTParty. Try changing that to ::HTTParty to specify the root namespace.
The big picture issue, looking back on this issue, was that I probably just needed to activate my /lib folder within rails via this addition to config/application.rb
config.autoload_paths += Dir["#{config.root}/lib/**/"]
from there, code can be directly loaded via the file_name.rb => FileName class system from anywhere within rails
I am having a perplexing problem. I want to call one ruby script from another.
With this in mind, I create a testscript.rb and executed it, it contains this code,
require './paypal.rb'
puts paypal['L_AMT0']
This code returns a number, which is my paypal balance. It relies on a paypal.rb file which uses the ruby-paypal gem. When I do ruby testscript.rb I get the output of my paypal balance, which means it is working properly. This tells me that my method for calling one RB from another is okay, since, in the above scenario, testscript.rb is getting a variable that is returned from paypal.rb.
Using this same logic, I inserted the above code into another program which is called SiriProxy. It is a ruby program. I need it to get my paypal balance.
So Inside that program, I did a require paypal.rb, it failed because it could not find it, so I set an absolute path in require which fixed it.
However, when SiriProxy (the other ruby rb giving me an issue) trys to run puts paypal['L_AMT0'] it results in an error and ends the program.
This is the error,
[Info - Plugin Manager] Say: Checking Paypal Balance
/home/siriproxy/.rvm/gems/ruby-1.9.3-p194#SiriProxy/gems/siriproxy-0.3.0/plugins/siriproxy-example/lib/siriproxy-example.rb:47:in `block in <class:Example>': undefined local variable or method `paypal' for #<SiriProxy::Plugin::Example:0x931a228> (NameError)
from /home/siriproxy/.rvm/gems/ruby-1.9.3-p194#SiriProxy/bundler/gems/cora-1edcfb9073d5/lib/cora/plugin.rb:47:in `instance_exec'
from /home/siriproxy/.rvm/gems/ruby-1.9.3-p194#SiriProxy/bundler/gems/cora-1edcfb9073d5/lib/cora/plugin.rb:47:in `block (2 levels) in process'
In the above output it appears the issue is it does not understand "paypal", as seen here:
undefined local variable or method `paypal'
However, I do not understand why, since in testscript.rb I do the exact same thing and it works.
Can anyone help? Thank you.
Seems like #CodeGnome is right.
From the Kernel documentation:
require(name) → true or false
Loads the given name, returning true if successful and false if the
feature is already loaded.
require_relative(string) → true or false
Ruby tries to load the library named string relative to the requiring
file’s path. If the file’s path cannot be determined a LoadError is
raised. If a file is loaded true is returned and false otherwise.
Loading Files from the Current Directory
I don't know anything about your library or its internals, but it looks like your require statement may be wrong. If you want to load a file from the current directory in Ruby 1.9.3, you should use:
require_relative 'paypal'
Bundler and Gems
If it's a gem that you've installed as part of a bundle (e.g. the gem is defined in a Gemfile), then providing a path in your require statement is wrong. Instead, you need to require the bundled gem as follows:
require 'bundler/setup'
require 'paypal'