Add Bundler 2.4 to documentation

Including release blog post and What's new page.

source/blog/2023-01-31-bundler-v2-4.html.markdown

@@ -0,0 +1,167 @@
+---
+title: "Bundler v2.4: new resolver, gems with Rust extensions, and more"
+date: 2023-01-31 14:43 UTC
+tags:
+author: David Rodríguez
+author_url: https://github.com/deivid-rodriguez
+category: release
+---
+
+2022 has been a busy year for the Bundler team, and we're glad to present
+several improvements that we hope will make our users happy :)
+
+## A better, PubGrub based, resolver
+
+Bundler now uses the most advanced algorithm to resolve versions, PubGrub.
+Kudos to Natalie Weizenbaum for [inventing
+it](https://nex3.medium.com/pubgrub-2fb6470504f) and to John Hawthorn for
+[porting it to Ruby](https://github.com/jhawthorn/pub_grub)!
+
+Our previous resolver, [Molinillo](https://github.com/CocoaPods/Molinillo), worked pretty well, but it really got in the
+middle when it didn't.
+
+This may sound familiar for some:
+
+~~~
+$ bundle
+Fetching gem metadata from https://rubygems.org/............
+Resolving dependencies....................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................^C
+$ # Ok, that was enough waiting
+~~~
+
+Our new resolver, PubGrub, is usually much faster, because it learns from the
+resolution conflicts it finds during the resolution process to avoid redoing the
+same work over and over again. You can find more about this "conflict-driven
+clause learning" techniques in its [presentation blog
+post](https://nex3.medium.com/pubgrub-2fb6470504f) back from 2018.
+
+Molinillo sometimes took too long to resolve because it would try the same
+things, backtrack, and run into the same conflicts over and over again, having
+to traverse very inefficiently a huge search space. But that was a relatively
+rare case in the real world.
+
+What's probably more common is specifying version requirements in your Gemfile,
+that can't be all satisfied at the same time. This is when the version solving
+problem does not have a solution, and when it becomes crucial to explain to users
+_why_, so that they can fix their set of version requirements to become
+solvable.
+
+Molinillo run into trouble here, and in cases with many moving parts, like
+upgrading Rails for example, it could end up printing a lot of conflicts, not
+easy to understand and solve. This is an old example from a public ticket:
+
+~~~
+Bundler could not find compatible versions for gem "actionpack":
+  In Gemfile:
+    inherited_resources (= 1.6.0) was resolved to 1.6.0, which depends on
+      actionpack (>= 3.2, < 5)
+
+    rails (= 4.2.0) was resolved to 4.2.0, which depends on
+      actionpack (= 4.2.0)
+
+Bundler could not find compatible versions for gem "activesupport":
+  In Gemfile:
+    inherited_resources (= 1.6.0) was resolved to 1.6.0, which depends on
+      has_scope (~> 0.6.0.rc) was resolved to 0.6.0, which depends on
+        activesupport (>= 3.2, < 5)
+
+    rails (= 4.2.0) was resolved to 4.2.0, which depends on
+      activesupport (= 4.2.0)
+
+Bundler could not find compatible versions for gem "railties":
+  In Gemfile:
+    inherited_resources (= 1.6.0) was resolved to 1.6.0, which depends on
+      railties (>= 3.2, < 5)
+
+    rails (= 4.2.0) was resolved to 4.2.0, which depends on
+      railties (= 4.2.0)
+
+    inherited_resources (= 1.6.0) was resolved to 1.6.0, which depends on
+      responders was resolved to 1.1.2, which depends on
+        railties (>= 3.2, < 4.2)
+~~~
+
+Not easy to know what to do about it.
+
+With PubGrub, you should now get human-readable explanations of failures. The
+most complex cases may are still, well... complex. But explanations should
+always make sense and point to the root cause of resolution failures.
+
+Here's an example from our test suite:
+
+~~~
+Because every version of c depends on a < 1
+  and every version of b depends on a >= 2,
+  every version of c is incompatible with b >= 0.
+So, because Gemfile depends on b >= 0
+  and Gemfile depends on c >= 0,
+  version solving has failed.
+~~~
+
+We tried to make this migration as backwards-compatible as possible, but
+there's a chance of experiencing some different solutions to the ones found by
+Molinillo, since the version solving problem does not have unique solutions.
+Please report any issues you find with the new resolver.
+
+
+### Easily generate gems with Rust extensions using `bundle gem`
+
+It's now easier than ever to get started using Rust inside your gems. Check out
+[this blog post](rust-gem-skeleton.html) to learn how to generate a gem with all
+the boilerplate necessary with just a few commands.
+
+### Faster git sources
+
+In the Bundler world, it's common to point to git repositories when there's
+no version released to rubygems.org that includes the changes that you need.
+This works fine, but it can get slow and use a lot of disk space when dealing
+with very big repositories.
+
+We have improved the way we clone these repositories to be faster and use less
+disk space. For example, something like
+
+```ruby
+gem "rails", github: "rails/rails"
+```
+
+in your Gemfile could previously take ~30s and use up to 1Gb of disk space,
+because we would clone the full Rails repository, which has a large history.
+
+Now we just clone what's strictly necessary for Bundler to work, resulting in
+big disk space savings, and much faster bundling.
+
+### New CLI features
+
+We added a few small CLI features, such as a new `--pre` flag to `bundle update`
+and `bundle lock` to explicitly opt-in to prereleases of selected (of all) gems
+without having to explictly change your Gemfile with pre-release requirements
+such as `>= 7.1.0.beta`.
+
+### Some minor breaking changes
+
+We took new year's release to move on and get rid of some stuff that was causing
+maintenance burden for us:
+
+* Ruby 2.3, 2.4, and 2.5 are no longer supported.
+* RubyGems 2.5, 2.6, and 2.7 are no longer supported.
+
+In general, this support drop should not break anything because RubyGems should
+be able to choose the latest supported Bundler on the Ruby version that you're
+using. But there are still some old RubyGems out there that don't have this
+feature, and the `gem install bundler` command could break there. We have
+warned using Bundler on those old rubies for a year now, so we believe it's time
+to move on.
+
+We also completely removed a controversial (mis-)feature from the Bundler code
+base, where Bundler would automatically acquire sudo permissions when not having
+the proper access rights. A great majority of users considered this feature harmful and
+hardly useful, so we decided to get rid of it.
+
+### And bug fixes
+
+As always, we continue to smooth the experience of using Bundler, so that it
+gets the job done and does not get in the middle other than that. And we're also
+shipping a bunch of bug fixes to keep moving towards that goal.
+
+That's all from the Bundler team. Have a happy new year, and enjoy using Bundler
+2.4! 🎉

source/v2.4/whats_new.html.md

@@ -1,4 +1,35 @@
 # What's New in v2.4
 
-As always, a detailed list of every change is provided in
+The [Bundler 2.4 announcement](/blog/2022/12/22/bundler-v2-4.html)
+includes context and a more detailed explanation of the changes in this version. This is a summary of the biggest changes. As always, a detailed list of every change is provided in
 [the changelog](https://github.com/rubygems/rubygems/blob/3.4/bundler/CHANGELOG.md).
+
+### A new PubGrub based resolver
+
+Bundler now uses [pub_grub](https://github.com/jhawthorn/pub_grub) under the
+hood to resolve versions. The most advance algorithm to approach the version
+solving problem! 💪
+
+### Generate gems with Rust extensions
+
+`bundle gem` now supports Rust! Pass the `--ext=rust` flag to generate a gem
+with a Rust extension.
+
+### Faster git sources in Gemfile
+
+Git sources in Gemfile now work faster and use less disk space.
+
+### Old Ruby and RubyGems no longer supported
+
+Support for Ruby 2.3, 2.4, and 2.5, and RubyGems 2.5, 2.6, and 2.7 has been dropped.
+
+### No more auto-sudo
+
+Bundler no longer tries to use `sudo` to upgrade privileges under any circumstances.
+
+### Other improvements
+
+Bundler 2.4 also includes other improvements like a new `--pre` flag
+to `bundle lock` and `bundle update` to explicitly opt-in to prereleases.
+
+<a href="https://github.com/rubygems/rubygems/blob/3.4/bundler/CHANGELOG.md" class="btn btn-primary">Full 2.4 changelog</a>