• Try to avoid versioning problems by keeping Ruby and all your gems up to date. See Staying up to date


Ruby is a great language in many ways, but the one thing that mars the experience of working with Ruby is the fact that you’ll often find yourself having to halt development work while you fix confusing Gemfile errors such as “Your Ruby version is 2.6.3, but your Gemfile specified 2.6.5” or .”Could not find gem ‘bundler (~> 1.1)’, which is required by gem ‘middleman-core (= 3.3.7)’, in any of the sources.”

I can’t decide whether I should be proud or ashamed of the fact that for a long time, my reaction to these errors was to google them and then blindly follow the advice I found until things were working again. Proud, because I was focused and pragmatic - I had a goal in mind and didn’t want to be distracted by the rabbithole of researching exactly what was going on. Ashamed, because I was doing the equivalent of hitting it with a hammer until it worked - rather than getting a proper understanding and therefore the ability to find long term solutions and be confident that I wouldn’t find myself back in the same situation at some unpredictable point in the future.

If you look at my Jekyll troubleshooting page, you’ll see that I was simply recording error messages and solutions, with not much idea of what was actually going on or which actions were the ones that actually fixed my problems, and not much understanding of why things got fixed when they did.

So today I have put aside a whole day to dive in and get to grips once and for all with what the hell is going on with my Gemfile.

Useful resources

Overview of versioning problems that can happen with Ruby projects

There are two possible sources of version woes when working Ruby:

  1. Problems with versions of the gems (aka packages) your Ruby project is using.
  2. Problems with the version of Ruby your project is using.

These can sometimes be related - eg your project may depend on a particular gem that itself is dependent on a particular version of Ruby. Generally though, the two areas are handled by different means:

  1. You can simply have gems manually installed on your system, using gem commands. But most Ruby projects use bundler to manage gem versions. This leads to the use of a file called Gemfile, which will itself specify your Ruby version (in different ways depending on which Ruby version management system you’re using).
  2. There are various different tools available to manage differing versions of Ruby between projects.

What gems are / how gems work

You can use the gem command to use the RubyGems software to find and install gems on your system. First you have to have RubyGems installed, but Ruby 1.9 and newer ships with RubyGems built-in. Every time you install a gem using gem install, it will download the gem from and install it on your system. It will also download and install any dependencies that the original gem relies on, and so on for any dependencies of dependencies.

A gem is a Ruby software package. Each gem contains a packaged Ruby application or library. More concretely, it’s a zip file containing a bunch of ruby files and/or dynamic library files that can be imported by your code, along with some metadata.

You can install gems using the gem install command, and there are lots of other useful gem commands (eg gem list to see what’s installed - more here) but this on its own does not allow you to control which gems are used by which projects. That’s where bundler comes in.

More on gems here

Staying up to date

  • See also Different versions of Ruby
  • NB: You should aim to always keep your Ruby version at the most stable version (in Jan 2021 this is 3.0.0).
    • To find the latest stable version, go here.
  • For advice on how to keep ALL your dependencies (ie gems as well as Ruby itself) up to date, see this article - which also gives advice on how to automate the process. GitHub’s dependabot will also help with this.
  • …or follow this simple approach (there are some notes here re when I did this on 1/3/21 - see commits cd73da4 to d9548ea):
      1. Make sure all dependabot PRs are acted on (instructions here)
      1. Make sure dependabot security alerts are also acted upon (not the same as PRs) (they happen when PRs are not possible - see how dependabot works) (instructions here)
      1. Run bundle-audit weekly or monthly and act on all recommendations (instructions here)
      1. Make sure your main technologies are up to date (for this site, that’s Ruby and Jekyll)
      1. Run bundle outdated at regular intervals and then run bundle update [gem-name] one at a time on each of the outdated gems, with a separate commit for each gem (fixing any related deprecation warnings in the same commit) (more detail here)

Acting on security recommendations with bundle audit

  • Install bundle-audit (if not done already)
    • gem install bundle-audit (or add to Gemfile)
  • Run bundle-audit on command line
  • Act on recommendations ONE AT A TIME, with a separate commit for each one and testing as you go.
    • eg if rack is listed as a vulnerability, run bundle update rack
    • or if you are advised to remove a gem altogether:
      • Search the code for all references (and remove them)
      • Then remove the gem from Gemfile
      • See commits bcdd478 and ccac302 for an example

Updating from dependabot branches

  • See also How dependabot works
  • Actions you can take:
    • If dependabot branches are failing in Travis:
      • Check / Google error messages in Travis
      • Switch locally to the dependabot branch
        • eg git checkout dependabot/bundler/activesupport-
      • Make any changes designed to fix deployment errors
        • eg see commit 15802e3
        • this was when I’d fixed some deployment problems in the main branch but they weren’t in the dependabot branch, so I copied them to the dependabot branch for experimentation
      • Push the branch to the remote, and check the build log in Travis to see if it’s fixed the problems
      • IMPORTANT: Test locally. Does the site still work?
      • If all is fine, merge the dependabot branch (in, visit Pull Requests at the top of the repo)
        • If GitHub says there are merge conflicts:
          • Merge the main branch into the dependabot branch locally (git merge main or git merge master) and fix conflicts there before merging
      • IMPORTANT: Test the deployed site too!
      • DON’T FORGET: If you merged the PR at, you won’t have the updated main branch locally until you run git pull (or git pull --rebase)

Acting on dependabot alerts

  • See also How dependabot works
  • Dependabot alerts live on the main front page in GitHub
  • or visit Security Dependabot alerts
  • They require a little more attention - see details in GitHub
  • You may have to remove a gem altogether:
    • Search the code for all references (and remove them)
    • Then remove the gem from Gemfile
    • See commits bcdd478 and ccac302 for an example

How dependabot works

  • See also Updating from dependabot branches
  • Dependabot is a free service offered by GitHub - you can enable it there
  • !! It does NOT necessarily catch all critical security updates. It’s worth using bundle-audit as well
    • gem install bundle-audit (or add to Gemfile) then run bundle-audit
    • although be aware that dependabot creates security alerts as a separate process to its main PRs - see below
  • Dependabot identifies dependency updates and creates pull requests suggesting you update your dependencies.
    • If you don’t merge the pull requests, they are not merged into your code base.
    • The PRs create new branches and automatically trigger Travis deploys (or whatever CI integration you’re using). This is why you sometimes get failed builds that mention dependabot - it’s because Travis is trying to build the PR branch.
    • It will actually trigger TWO Travis builds I think - one for what would happen if you built the dependabot branch as-is (“branch”), and one for if you built the branch merged into the main branch (“pull request”)
      • If you click through to the PR in GitHub, you’ll see something like “all checks have passed”
      • Then you can click “Show all checks” and you’ll see see two Travis builds - one for “branch” and one for “pull request”
      • If you click Details on the right, it will take you through to Travis
    • I think maybe every time you push new changes, the PR branch is automatically updated and Travis runs another build? Or it just keeps re-running them at regular intervals?
    • Sometimes the PRs are closed automatically - for instance if you run a bundle update yourself and your dependencies are updated, so dependabot detects that the PR is no longer needed. Or because you make changes to your Gemfile so that the dependency that dependabot is trying to update is no longer even a dependency of your project.
    • As well as PRs, there are also dependabot alerts
    • These happen when PRs can’t be created - for instance because conflicting dependencies prevent an update to a non-vulnerable version
    • These will live on the main front page in GitHub
    • or visit Security Dependabot alerts

Different versions of Ruby

Mac (OSX) and Linux

  • The below notes are now probably out of date.
  • The three main Ruby version management systems for Mac OSX and Linux (including WSL on Windows, but NOT vanilla Windows via GitBash) are:
    • chruby
      • This is what I’m currently using, via my Ubuntu system on Windows (NOT Ubuntu 16.04 (just because Ubuntu is the one I keep up to date and has everything in ~/.bashrc))
      • To list Ruby versions currently installed, just enter chruby at the command prompt.
      • To switch to a new version of Ruby do the following:
        • If the new version not already installed:
          • Cmd: ruby-install ruby 2.6.5
          • Restart your shell by typing exit and then restarting.
        • Then run cmd chruby ruby-2.6.5 to switch to the new version. You can also put this command into your ~/.bashrc to effectively make that version your default, but remember to edit it when you upgrade Ruby!
      • More on chruby here and here
    • rvm
    • rbenv
    • Here is a brief discussion / comparison of all three.
  • No matter which system you use, the file .ruby-version can be used to specify your Ruby version. This is then referred to in Gemfile like this: ruby"../.ruby-version", __FILE__)).strip


If you’re coding Ruby in Windows, you’ll be using RubyInstaller. More here. But that doesn’t seem to allow you to switch between Ruby versions.

The solution is to either use WSL or WSL2 to run a Linux subsystem on your Windows machine, or use something like pik or URU, which are separate Ruby version managers for Windows.

Basic package management from RubyGems

  • Even without bundler you get some package management - via rubygems.rb.
    • The basic gem command is defined by RubyGems
  • Your $LOAD_PATH Ruby environment variable (only accessible to Ruby) holds the paths that Ruby searches when looking for gems (eg when executing load and require commands).
    • You can see all your Ruby environment variables by running gem environment on the command line.
    • NB When rubygems.rb is loaded, it replaces the default require with a new version that also searches installed gems as well as searching $LOAD_PATH - and updates $LOAD_PATH on the fly to add the directory/ies specified by the installed gem.
      • Actually I’m not sure it does update $LOAD_PATH any more. When I tested this with irb by running puts $LOAD_PATH.grep(/json/) and then require('json') and then puts $LOAD_PATH.grep(/json/) again, I didn’t get the effect described in this article.
      • rubygems.rb gets loaded when you run irb. It also gets loaded when you run any Ruby program, as long as you are using Ruby v1.9 or later. Otherwise you have to specifically add it into your app using require 'rubygems'
    • Be aware that if you’re building your own gem, there’s a lot of good practice to make sure you don’t cause problems with $LOAD_PATH More on this here.
    • Gems are installed by running the gem install command
      • You can see where they are installed by running gem environment and checking the setting for INSTALLATION DIRECTORY.
      • Installing a gem means downloading its code from (if you have that configured as your gem source - you can check that via gem environment) and compiling any C code into dlls.
      • If you use bundler and have a Gemfile instead of using gem install, then when you run bundle install it does the same as gem install, and makes sure the specified version is installed. You could replicate this by manually running gem install for all the relevant gems and their versions (but probably wouldn’t want to).
        • Installing a specific version of a gem means that its directories are added to $LOAD_PATH and its activation is recorded. You can’t simultaneously activate two versions of the same gem.
    • Questions:
      • Is the change to $LOAD_PATH made by Rubygems require temporary or permanent?
        • See above. I suspect it’s not even true any more, but I’m pretty sure that when it was it was only temporary.
      • If you can’t simultaneously activate two versions of the same gem, does this mean you can’t simultaneously have two Ruby programs running that use different versions of the same gem?
        • I think the answer to that is yes - if you use a bundle exec command for each programme, then it just means bundler will load the correct version when starting the relevant piece of software. Once it’s running, the correct version is loaded into memory and everything continues happily?
  • When you use require to load a file, it will update the $LOADED_FEATURES Ruby environment variable.
    • It will also execute all the code in required gem - which might involve requiring other gems, and will mean that various methods (and maybe some global variables) get defined.
  • The difference with require (as opposed to load) is that it will not load the same code twice (it will return false instead).
    • Also, you can use require_relative to search in the same location as the file containing the require command (instead of searching $LOAD_PATH).
  • You can test this via irb with the following series of commands (create a file foo.rb in the current directory):
  • You might have to hunt through the long list of output, but foo.rb will be in there somewhere (quite likely at the end, in fact).


NB: Try to avoid versioning problems by keeping Ruby and all your gems up to date. See Staying up to date.

  • Run bundle init to create a brand new Gemfile.
  • bundler is itself a gem, which has to be installed like other gems (gem install bundler).
  • bundler is a gem package manager.
    • Interestingly RubyGems is also a package manager - the default one you’re using if you don’t have a Gemfile (and are therefore not using bundler), and you have Ruby v1.9 or higher… or you have require 'rubygems' in your project.
    • Most people use bundler though (which itself uses rubygems).
  • Once you have it installed, you can use Gemfile to specify your dependencies and (if you want) make broad (or specific) specifications about their versions.
    • Then when you run bundle install, bundler will install everything specified in your Gemfile AND all the dependencies of those gems, and their dependencies… all the way up the dependency tree.
    • Once it’s done, it creates Gemfile.lock which lists the exact version currently installed for every gem and every dependency.
    • You should check Gemfile.lock into source control so that you know exactly what versions of gems you are using for each commit. The exception to this is when you’re building a library - in which case you only commit Gemfile. The reason for this is that your library could end up being just one link in a dependency chain, and other versions may be required of upstream or downstream dependencies (I think).
  • In your Gemfile, this is the notation used to express version preferences:
    • ~> 1.1 means version 1.1 or later, but only if it’s prefixed 1.1. So 1.1.5 would be installed, but 1.2 would not.
      • Like this: gem "redcarpet", "~> 3.4"
    • >= 1.1 would mean version 1.1 or later, including 1.2, 1.3 and even 7.2.
      • Like this: gem "redcarpet", ">= 3.4"
    • 1.1 specifies an exact version (not recommended)
      • Like this: gem "redcarpet", "3.4"
  • If you use bundler and have a Gemfile instead of using gem install, then when you run bundle install it does the same as gem install, and makes sure the specified version is installed. You could replicate this by manually running gem install for all the relevant gems and their versions (but probably wouldn’t want to).
  • Putting bundle exec before a command, e.g. bundle exec rspec, ensures that require will load the version of a gem specified in your Gemfile.lock as opposed to the most recent version.
  • If you’re using bundler, then you should add these two lines to the first file your application loads:
require 'rubygems'
require 'bundler/setup'
  • (If you’re using Ruby 1.9 or later then you don’t actually need the first line)
  • What bundler/setup does is alter your $LOAD_PATH so that only the gems in your Gemfile are put into $LOAD_PATH.
    • This is useful because if you had installed a gem on your machine using gem install, and then required it in your code, but hadn’t added it to your Gemfile, then anybody else downloading your code would get errors. This way you will also get the same errors, and that will remind you to add the gem to your Gemfile.
    • More here and here.
  • You can use Bundler.require(:default) as shorthand to require everything in your Gemfile.
  • Bundler will not update dependencies of dependencies if it means the resulting gem will be a version incompatible with another gem that also depends on it.
  • Question:
    • Why didn’t bundler/setup work in server.rb when I removed omniauth but left the require statement in server.rb?
    • In commit ccac302 I made the relevant changes to server.rb, because in the previous commit I’d removed omniauth from Gemfile, and everything went fine locally… but when I deployed to hroku I got server errors saying there was a require statement for ominauth but no gem.
    • I assumed this was because I hadn’t done the bundler/setup thing, but when I experimented locally by adding bundler/setup but leaving the require ijn place, everything still worked fine locally - when I would have expected to see the same error I saw in heroku.
    • The original place I learnt about bundler/setup was here

Useful Bundler commands

  • Update all gems: bundle update (exercise caution though)
    • The documentation on bundle update is quite good but you have to read it thoroughly and carefully!
    • bundle update won’t update beyond Gemfile versions, and you can use major and minor to specify version details (see documentation), or you can change versions in Gemfile and run bundle install. If you don’t run bundle update and just run bundle install a second time after having already run it once, you won’t get newer versions of gems even if they exist - it will just use whatever is in Gemfile.lock and won’t update anything. bundle update with no qualifiers will update everything, but won’t go beyond the versions specified in Gemfile.
  • Update multiple gems: bundle update gem1 gem2 gem3
    • This can be very useful if you’re trying to update one gem and keep getting errors about other related gems relying on different versions of each other - just update them all at once.
  • Update one gem (and its dependencies): bundle update gem-name
    • To update it to a particular version, specify the version in Gemfile and then run bundle install
    • ~> 1.2.1 means version 1.2.1 or later, but only if it’s prefixed 1.2. So 1.2.5 would be installed, but 1.3 would not.
      • Like this: gem "redcarpet", "~> 3.4"
    • >= 1.1 would mean version 1.1 or later, including 1.2, 1.3 and even 7.2.
      • Like this: gem "redcarpet", ">= 3.4"
    • 1.1 specifies an exact version (not recommended)
      • Like this: gem "redcarpet", "3.4"
  • Find out which gems are outdated: bundle outdated
  • Find out which gems have security vulnerabilities: Use bundle-audit: gem install bundle-audit (or add to Gemfile) then run bundle-audit

Errors / problems you might see

Trouble getting Ruby working on a 2022 Macbook

  • (Seen by me when trying to get set up for the Made Tech Academy, Feb 2022)
  • Getting Ruby working on a 2022 Macbook
  • “I followed the step in this article in my laptop to check my rbconfig, and found that the system ruby v.2.6.8 provided by Apple is indeed "host_cpu"=>"x86_64" , while the ruby v.2.6.9 that I installed via rbenv is "host_cpu"=>"aarch64" (=arm64). So perhaps some problem in apple’s default settings maybe…?”

“Your XXX version is a.b.c, but your Gemfile specified d.e.f”

(See also Conflicting Ruby versions below.)

  • Example:
    • Your Ruby version is 2.6.3, but your Gemfile specified 2.6.5
  • Explanation
    • Your installed version of Ruby is 2.6.3, but your Gemfile has specified that this project requires a different version.
    • This can happen on remote deployment platforms (eg Heroku) if you have pushed Gemfile but not Gemfile.lock (see below)
    • You might not find anything in your Gemfile which obviously specifies a Ruby version. Instead you might see something like this:
      • ruby"../.ruby-version", __FILE__)).strip
      • This indicates that you have a separate file called .ruby-version which tells you which version of Ruby your project is expecting
      • In my case my Gemfile and my .ruby-version are both in the same folder, so I don’t know why the path (../) specifies that the file is in the parent folder.
  • Solutions:
    • To find out which version of Ruby you have installed, type this at the command line: ruby --version
    • If this happens in Heroku, make sure you have checked in your Gemfile.lock as well as your Gemfile
    • Install the correct version of Ruby: ruby-install ruby 2.6.5
      • Note then when I had this problem, this wasn’t enough - I also had to run gem install bundler and then bundle install - see questions below
    • You might try using chruby, but when I did this it didn’t seem to work (see questions below):
      • Add stuff to ~/.bash_profile and .ruby-version as per
      • Cmd: which ruby
      • Cmd: chruby_use /Users/clarey/.rubies/ruby-2.6.5/
  • Questions:
    • Why did I also have to run gem install bundler and then bundle install?
    • What’s all that chruby stuff?
    • Why does Heroku need Gemfile.lock as well as Gemfile?

Conflicting Ruby versions

  • Example:
    • I got various errors about Ruby versions when I first set this site up.
  • Solutions:
    • I originally fixed the project at Ruby version 2.6.5 by adding a .ruby-version file and referring to it in Gemfile. But then my system version of Ruby got updated to 2.7.2 (probably because of academny-related Ruby stuff) and things got screwy again. Currently I can’t run jekyll serve because I get the error “Your Ruby version is 2.7.2, but your Gemfile specified 2.6.5”.
  • Questions
    • How can I stop this problem from recurring every time I update Ruby?
    • How can I keep Ruby up to date and avoid security weaknesses dur to not keeping Ruby and other dependencies up to date?
    • Are the following all equivalent alternatives to .ruby-version?
      • chruby
      • rvm
      • rbenv
  • Experiments:
    • Use .ruby-version to update the version of Ruby being used by this site.
    • Go back to Ruby version 2.6.5 system-wide. Check my other Ruby projects (academy stuff) aren’t broken by this.
    • Find a way of having more than one version of Ruby installed - so that this project can be fixed at a different version.
    • Once I have the Ruby version sorted, run jekyll serve to try and understand what all the mingw stuff is about. Or just use a previously-committed Gemfile.lock that contains the mingw stuff.
    • Update the Ruby version and then try to fix the formatting issue where the search box moves from right to left.

`warn_for_outdated_bundler_version’: You must use Bundler 2 or greater with this lockfile.

  • Explanation:
    • Presumably this comes from the “BUNDLED WITH” section at the bottom of Gemfile.lock (see questions below).
  • Solution:
    • gem install bundler
  • Questions:
    • Presumably you could also be more specific and run something like gem install bundler -v 2.0?
    • What’s the difference between having a version specified in Gemfile and having it specified in Gemfile.lock? The lock file tends to have a lot more version specifications than Gemfile, and Heroku complains if it doesn’t have a lock file checked in.
    • There’s no reference to bundler in Gemfile, but it does say “BUNDLED WITH” and a version number at the bottom of Gemfile.lock. Presumably this is where the error comes from?

“Could not find gem ‘YYY (~> a.b)’, which is required by gem ‘ZZZ (= c.d.e)’, in any of the sources.”

  • Example:
    • Could not find gem 'bundler (~> 1.1)', which is required by gem 'middleman-core (= 3.3.7)', in any of the sources.
  • Explanation:
    • It can’t find a particular version (~> 1.1) of a particular gem (bundler), because another gem (middleman-core, currently at version 3.3.7)) has specified that it is dependent on the missing gem.
    • ~> 1.1 means version 1.1 or later, but only if it’s prefixed 1.1. So 1.1.5 would be installed, but 1.2 would not.
    • >= 1.1 would mean version 1.1 or later, including 1.2, 1.3 and even 7.2.
  • Solution:
    • Install the correct version of bundler and then reinstall middleman:
      • Cmd: gem install bundler -v 1.15
      • Cmd: bundle _1.15_ install
      • Cmd: gem install middleman
  • Questions:
    • Those actions above are just what I did before things started working again - doesn’t mean they were the correct or best solution. So…
      • Did I really need to reinstall middleman?
      • What’s the difference between the first and second lines?

“can’t find gem bundler (>= 0.a) with executable bundle (Gem::GemNotFoundException)”

  • Example:
    • “/home/travis/.rvm/rubies/ruby-2.5.1/lib/ruby/2.5.0/rubygems.rb:308:in activate_bin_path’ /home/travis/.rvm/rubies/ruby-2.5.1/lib/ruby/2.5.0/rubygems.rb:289:infind_spec_for_exe’: can’t find gem bundler (>= 0.a) with executable bundle (Gem::GemNotFoundException)”
  • Explanation:
    • This happened to me when deploying on Travis. If you look closely, you’ll see it was in a Travis Ruby 2.5.1 directory. This seemed to come from the fact that I had rvm version 2.5.1 specified in .travis.yml.
  • Solution:
    • I changed the rvm section of .travis.yml to match .ruby-version.
      • Something that confused me is that this section is not specifying the version of rvm, it’s specifying the version of Ruby.
  • Example:
    • Running jekyll serve on my Windows machine (for this website) results in Windows-related dependencies being added to your Gemfile.lock (gems like eventmachine (1.2.7-x64-mingw32) are added, and a new x64-mingw32 entry is added in the PLATFORMS section at the bottom), which then causes Heroku to complain that your Gemfile.lock was created by Windows.
  • Explanation:
    • Maybe jekyll serve picks up on local platform settings and installs the relevant gems?
  • Solutions:
    • My main workaround is that I either manually remove all those mingw32 entries or I just don’t check in the altered version of Gemfile.lock.
    • Instead, could fix Gemfile.lock by running the bundle command in Ubuntu and then pushing the resulting Gemfile.lock up to the server?
  • Questions:
    • What’s actually happening here? And is there a better solution?

“cannot load such file”

  • You might need to run bundle install
    • If that doesn’t work, it might mean that you have not added the specified gem to your Gemfile.
    • For instance if you get “cannot load such file – rspec/core/rake_task”, then try adding gem 'rspec' to your Gemfile.
  • If you get “command not found: bundle” then you might need to install Bundler: sudo gem install bundler
    • !! The password it wants is your laptop password

Things you might do to fix a problem

gem install bundler

  • Example:
    • gem install bundler
    • Note that this is typically folowed by bundle install
  • Explanation:
    • bundler is a gem package manager
  • Questions:
    • Presumably bundler is itself a gem?
    • How does it know about versions of gems? Does it rely on Gemfile?
    • Will Gemfile work if you don’t have bundler installed, or is Gemfile proprietary to bundler?
    • Can you manage gems using other systems, or do you have to have bundler?

bundle install

  • Example:
    • bundle install
  • Explanation:
    • This installs all the gems specified in your Gemfile
  • Gotchas:
    • Note that in Ubuntu 16 on Windows (using WSL), when I ran the bundle command to install rake, I had to add some permissions: sudo chown -R claresudbery:claresudbery /home/claresudbery/.bundle
  • Questions:
    • Locally or globally?
    • Presumably you need bundler installed?
    • Can you have a functioning Gemfile without having bundler installed?
    • What does it mean to say that gems are installed?

bundle update

  • Example:
    • bundle update
  • Explanation:
    • Sometimes when you run bundle install, you get a message saying you need to run bundle update first. In this case you should… run bundle update first!
    • But be aware that bundle update will ignore Gemfile.lock and update ALL dependencies, which can have unexpected results.
      • A less aggressive approach is to run bundle update on a specific package, like this: bundle update rack-cache. Then only that package and its dependencies will be updated.
      • However, bundler will not update the dependency of an updated gem if it means the resulting dependency will be a version incompatible with another gem that also depends on it.
  • Questions:
    • What does bundle update do?
    • Why does it sometimes need running before bundle install?

gem update

  • Example:
    • gem update
    • (Note that in Linux on Windows, I first had to run sudo chown -R claresudbery /var/lib/gems/2.5.0/ to avoid permissions errors)
  • Explanation:
    • ???
  • Questions:
    • Is this the equivalent of bundle install if you don’t have bundler installed?
    • I used this command on Linux in Windows. Is that relevant?

gem install XXX

  • Example:
    • gem install middleman
  • Explanation:
    • You’re installing the specific gem called middleman
  • Questions:
    • Presumably because you haven’t specified a version, you will get the latest release?

gem install XXX -v a.b

  • Example:
    • gem install bundler -v 1.15
  • Explanation:
    • You’re installing a specific version (1.15) of a specific gem (bundler)

gem install XXX YYY

  • Example:
    • gem install bundler jekyll
  • Explanation:
    • You’re installing two gems at once (bundler and jekyll)
  • Questions

bundle a.b install

  • Example:
    • bundle _1.15_ install
  • Explanation:
    • ???
  • Questions:
    • Is this something that only works on the version of bundler - because it’s using the bundle command to update itself - or if would this work on any gem, and in this case the gem in question is bundle?
      • I suspect the former, because I don’t think there is a gem called bundle - the gem (if it even counts as a gem?) is called bundler. I could be wrong though.

bundle exec xxx

  • Example:
    • bundle exec jekyll build
  • Explanation:
    • You’re prefixing command-line operations with bundle exec
  • Questions:
    • Is this so that everything you run will only use gems that have been installed using bundler?
    • Does it mean you make sure you only use the gem versions specified locally for that project?
    • Does it only work for command line operations?
    • Does it only work when the things you are running on the command kine are themsleves gems?- If you get the error

Use chruby to manage your Ruby versions

  • See also Different versions of Ruby in this doc.

  • Example:
    • Add stuff to ~/.bash_profile and .ruby-version as per
    • Cmd: which ruby
    • Cmd: chruby_use /Users/clarey/.rubies/ruby-2.6.5/
  • Another example:
    • Cmd: brew install chruby
    • Cmd: source /usr/local/share/chruby/
    • Cmd: source /usr/local/share/chruby/
  • Explanation:
    • You’re using chruby to manage which version of Ruby is used by this project
  • Questions:
    • Does this mean that different projects can use different versions of Ruby?
    • What’s the difference between the two examples above?
    • What are the other tools that can be used to manage Ruby versions - eg rvm?
    • How come Travis appears to rely on rvm (hence the section in .travis.yml used to specify your Ruby version) even though I’m not? Presumably this is because Travis is using rvm locally on its own servers?

Use ruby-install to specify a Ruby version

  • See also Different versions of Ruby in this doc.

  • Example:
    • Cmd: brew install ruby-install
    • Cmd: ruby-install ruby 2.6.5
  • Explanation:
    • ruby-install is what you use to install Ruby. In this case you’re specifying a particular version
    • Note that you might not have brew installed on your system.
      • If you’re in Windows, I think you have to use a dedicated installer.
      • If you’re on a Mac or Linux, I think yarn is one of the alternatives to brew?
      • If you’re on Linux, the equivalent to brew install is often (always?) sudo apt-get install
      • Fwiw personally I like using brew when I’m on a Mac - it allows me to have a brew script which I can use to set up a new Mac with all my preferred software.
  • Questions:
    • If you don’t specify a version, will you get the latest stable release?
    • Are there other Ruby installation tools available other than ruby-install?
    • Can you have old versions of Ruby hanging around on your system?
      • I think there will be folders somewhere in your operating system that have particular versions in their names?

To do

  • Answer the questions in this doc
  • Update the academy gems presentation with any extra useful stuff I’ve learnt and documented here
  • Update clare-wiki
    • update Ruby version
    • Update gems
      • one at a time (see article below) - run bundle outdated and then bundle update gem-name on each of the outdated gems.
    • see this article - which also gives advice on how to automate the process.
      • try getting bummr working?
  • Fix problems with martin fowler
    • I made a change to class-too-large.xml which I didn’t push to the remote repo because I wasn’t able to test it locally.
      • There’s a backup in Dropbox at Desktop\Current\refactoring
      • If you run work and then rs you get the following error: “C:/Ruby27-x64/lib/ruby/gems/2.7.0/gems/bundler-1.17.3/lib/bundler/spec_set.rb:91:in `block in materialize’: Could not find ffi-1.11.2-x64-mingw32 in any of the sources (Bundler::GemNotFound)”
      • I’m pretty sure this is because it’s trying to use Ruby 2.7.0 (check out the folder in the path in the error message), and maybe the last time I ran it I was on Ruby 2.6.5?
        • I tried running everything in Linux (Ubuntu - not 16.04) instead, because that way I could use chruby to switch Ruby versions
        • I got as far as installing the required version of Ruby, but then when I tried to run bundle install I got the error “/usr/lib/ruby/2.5.0/rubygems.rb:284:in `find_spec_for_exe’: Could not find ‘bundler’ (1.17.3) required by your /mnt/c/development/sudbery-mfcom/Gemfile.lock. (Gem::GemNotFoundException)”
        • When I tried to install the correct version of bundler using gem install bundler -v 1.17.3, I got the error “Unable to require openssl, install OpenSSL and rebuild ruby (preferred) or use non-HTTPS sources” (I found this on stackoverflow, but didn’t have time to investigate further).
        • When I tried bundle _1.17.3_ install, I just got the same error as before (“Could not find ‘bundler’ (1.17.3)”)
        • I tried pulling latest changes from remote but that didn’t help either.
    • Once I get this working I need to test it locally before pushing it to the remote.
  • Answer unanswered questions in this doc
  • Update to WSL 2 on my machine