I'm doing some unit testing, and some of the code is checking to see if files exist based on the relative path of the currently-executing script by using the FILE variable. I'm doing something like this:
if File.directory?(File.join(File.dirname(__FILE__),'..','..','directory'))
blah blah blah ...
else
raise "Can't find directory"
end
I'm trying to find a way to make it fail in the unit tests without doing anything drastic. Being able to overwrite the __ FILE __ variable would be easiest, but as far as I can tell, it's impossible.
Any tips?
My tip? Refactor!
I didn't mark this as the real answer, since refactoring would be the best way to go about doing it. However, I did get it to work:
wd = Dir.getwd
# moves us up two directories, also assuming Dir.getwd
# returns a path of the form /folder/folder2/folder3/folder4...
Dir.chdir(wd.scan(/\/.*?(?=[\/]|$)/)[0..-3].join)
...run tests...
Dir.chdir(wd)
I had tried to do it using Dir.chdir('../../'), but when I changed back, File.expand_path(File.dirname(__ FILE __)) resolved to something different than what it was originally.
Programming Ruby 1.9 says on page 330 that __FILE__ is read only. It also describes it as a "execution environment variable".
However, you can define __FILE__ within an instance_eval. I don't think that'd help with your problem.
Related
The latest changesets to Ruby 1.9.2 no longer make the current directory . part of your LOAD_PATH. I have a non-trivial number of Rakefiles that assume that . is part of the LOAD_PATH, so this broke them (they reported "no such file to load" for all require statements that based off the project path). Was there a particular justification for doing this?
As for a fix, adding $: << "." everywhere works, but seems incredibly hacky and I don't want to do that. What's the preferred way to make my Rakefiles 1.9.2+ compatible?
It was deemed a "security" risk.
You can get around it by using absolute paths
File.expand_path(__FILE__) et al
or doing
require './filename' (ironically).
or by using
require_relative 'filename'
or adding an "include" directory
ruby -I . ...
or the same, using irb;
$irb -I .
There's two reasons:
robustness and
security
Both are based on the same underlying principle: in general, you simply cannot know what the current directory is, when your code is run. Which means that, when you require a file and depend on it being in the current directory, you have no way of controlling whether that file will even be there, or whether it is the file that you actually expect to be there.
As others answers point out, it's a security risk because . in your load path refers to the present working directory Dir.pwd, not the directory of the current file being loaded. So whoever is executing your script can change this simply by cding to another directory. Not good!
I've been using full paths constructed from __FILE__ as an alternative.
require File.expand_path(File.join(File.dirname(__FILE__), 'filename'))
Unlike require_relative, this is backward compatible with Ruby 1.8.7.
Use require_relative 'file_to_require'
Throw this in your code to make require_relative work in 1.8.7:
unless Kernel.respond_to?(:require_relative)
module Kernel
def require_relative(path)
require File.join(File.dirname(caller.first), path.to_str)
end
end
end
'.' in your path has long been considered a bad thing in the Unix world (see, for example, http://www.faqs.org/faqs/unix-faq/faq/part2/section-13.html). I assume the Ruby folks have been persuaded of the wisdom of not doing that.
I found this to be a confounding change until I realized a couple of things.
You can set RUBYLIB in your .profile (Unix) and go on with life as you did before:
export RUBYLIB="."
But as mentioned above, it's long been considered unsafe to do so.
For the vast majority of cases you can avoid problems by simply calling your Ruby scripts with a prepended '.' e.g. ./scripts/server.
As Jörg W Mittag pointed out, I think what you want to be using is require_relative so the file you require is relative to the source file of the require declaration and not the current working dir.
Your dependencies should be relative to your rake build file.
I have a chef recipe that looks something like this:
package 'build-essential' do
action :install
end
cmd = Mixlib::ShellOut.new("gcc -dumpversion")
cmd.run_command
gcc_version = cmd.stdout.strip()
If I execute the recipe on a system where gcc is installed, the recipe runs fine without errors. However, if I run the recipe on a system which doesn't have gcc install I get the error 'no such file or directory - gcc'.
I came to know about the chef two-phases stuff when trying to find a solution to my problem. I was expecting the package installation to satisfy the gcc requirement. How can I tell chef that this requirement will be satisfied later and not throw an error at compile time?
I tried the following, but the attribute does not get updated.
Chef::Resource::RubyBlock.send(:include, Chef::Mixin::ShellOut)
ruby_block "gcc_version" do
block do
s = shell_out("gcc -dumpversion")
node.default['gcc_version'] = s.stdout.strip()
end
end
echo "echo #{node[:gcc_version]}" do
command "echo #{node[:gcc_version]}"
end
Any help is appreciated. Thanks.
So okay, a few issues here. First, forget that Chef::Resource::whatever.send(:include trick. Never do it, literally never. In this case, the ShellOut mixin is already available in all the places anyway.
Next, and more importantly, you've still got a two-pass confusion issue. See https://coderanger.net/two-pass/ for details but basically the strings in that echo resource (I assume that said execute originally and you messed up the coping?) get interpolated at compile time. You haven't said what you are trying to do, but you probably need to use the lazy{} helper method.
And last, don't store things in node attributes like that, it's super brittle and hard to work with.
I'm currently testing mercurial hooks on windows and it seems like I cannot access hook variables....
here's hgrc content :
[hooks] prechangegroup = ruby prechangegroup.rb test1 test2 $HG_NODE
I also tried with %HG_NODE%
Here's prechangegroup.rb content
ARGV.each do|a|
puts "Argument: #{a}"
end
It prints out:
Argument: test1
Argument: test2
Argument: $HG_NODE$
Followed by the normal push output...
Any idea? (probably something stupid but, I can't seem to find it)
Thanks
HG_NODE is an environmental variable. You don't have to use it as arguments on the command line. Instead, you should be able to use it as puts ENV['HG_NODE'] (found through search engine as I'm not a ruby guy)
OK, I found a good documentation right on mercurial's website.
http://www.selenic.com/mercurial/hgrc.5.html#hooks
I tried with a variable other than %HG_NODE% like %HG_URL% and the variable worked.
So it probably means that the variable is inaccessible from that hook.
The latest changesets to Ruby 1.9.2 no longer make the current directory . part of your LOAD_PATH. I have a non-trivial number of Rakefiles that assume that . is part of the LOAD_PATH, so this broke them (they reported "no such file to load" for all require statements that based off the project path). Was there a particular justification for doing this?
As for a fix, adding $: << "." everywhere works, but seems incredibly hacky and I don't want to do that. What's the preferred way to make my Rakefiles 1.9.2+ compatible?
It was deemed a "security" risk.
You can get around it by using absolute paths
File.expand_path(__FILE__) et al
or doing
require './filename' (ironically).
or by using
require_relative 'filename'
or adding an "include" directory
ruby -I . ...
or the same, using irb;
$irb -I .
There's two reasons:
robustness and
security
Both are based on the same underlying principle: in general, you simply cannot know what the current directory is, when your code is run. Which means that, when you require a file and depend on it being in the current directory, you have no way of controlling whether that file will even be there, or whether it is the file that you actually expect to be there.
As others answers point out, it's a security risk because . in your load path refers to the present working directory Dir.pwd, not the directory of the current file being loaded. So whoever is executing your script can change this simply by cding to another directory. Not good!
I've been using full paths constructed from __FILE__ as an alternative.
require File.expand_path(File.join(File.dirname(__FILE__), 'filename'))
Unlike require_relative, this is backward compatible with Ruby 1.8.7.
Use require_relative 'file_to_require'
Throw this in your code to make require_relative work in 1.8.7:
unless Kernel.respond_to?(:require_relative)
module Kernel
def require_relative(path)
require File.join(File.dirname(caller.first), path.to_str)
end
end
end
'.' in your path has long been considered a bad thing in the Unix world (see, for example, http://www.faqs.org/faqs/unix-faq/faq/part2/section-13.html). I assume the Ruby folks have been persuaded of the wisdom of not doing that.
I found this to be a confounding change until I realized a couple of things.
You can set RUBYLIB in your .profile (Unix) and go on with life as you did before:
export RUBYLIB="."
But as mentioned above, it's long been considered unsafe to do so.
For the vast majority of cases you can avoid problems by simply calling your Ruby scripts with a prepended '.' e.g. ./scripts/server.
As Jörg W Mittag pointed out, I think what you want to be using is require_relative so the file you require is relative to the source file of the require declaration and not the current working dir.
Your dependencies should be relative to your rake build file.
[I'm just starting with Ruby, but "no question is ever too newbie," so I trudge onwards...]
Every tutorial and book I see goes from Ruby with the interactive shell to Ruby on Rails. I'm not doing Rails (yet), but I don't want to use the interactive shell. I have a class file (first_class.rb) and a Main (main.rb). If I run the main.rb, I of course get the uninitialized constant FirstClass. How do I tell ruby about the first_class.rb?
The easiest way is to put them both in the same file.
However you can also use require, e.g.:
require 'first_class'
You can also use autoload as follows:
autoload :FirstClass, 'first_class'
This code will automatically load first_class.rb as soon as FirstClass is used. Note, however, that the current implementations of autoload are not thread safe (see http://www.ruby-forum.com/topic/174036).
There's another point worth noting: you wouldn't typically use a main file in ruby. If you're writing a command line tool, standard practice would be to place the tool in a bin subdirectory. For normal one-off scripts the main idiom is:
if __FILE__ == $0
# main does here
# `__FILE__` contains the name of the file the statement is contained in
# `$0` contains the name of the script called by the interpreter
#
# if the file was `required`, i.e. is being used as a library
# the code isn't executed.
# if the file is being passed as an argument to the interpreter, it is.
end