Defect #37249: Missing rexml gem causes errors in PUT - Adding the gem manually everything works - Redmine

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Defect #37249

closed

Missing rexml gem causes errors in PUT - Adding the gem manually everything works

Added by Bubi = almost 2 years ago. Updated almost 2 years ago.

Status:

Closed

Priority:

Normal

Assignee:

Marius BĂLTEANU

Category:

Gems support

Target version:

5.0.2

Start date:

Due date:

% Done:

Estimated time:

Resolution:

Fixed

Affected version:

5.0.1

Description

Here the part of the log

App 19843 output: [599f0f62-257a-49a9-bf49-2d9cd67a9566] Started POST "/issues.xml?key=hidden" for hidden at 2022-06-14 14:47:42 +0000
App 19843 output: You don't have rexml installed in your application. Please add it to your Gemfile and run bundle install
App 19843 output: [599f0f62-257a-49a9-bf49-2d9cd67a9566] LoadError (cannot load such file -- rexml/document):
App 19843 output: [599f0f62-257a-49a9-bf49-2d9cd67a9566] zeitwerk (2.6.0) lib/zeitwerk/kernel.rb:35:in `require'

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Updated by Holger Just almost 2 years ago

Status changed from New to Confirmed

rexml used to be a a requirement of Rails as it is used as the default backend of ActiveSupport::XmlMini. This backend is used e.g. when parsing XML payloads of API requests.

In Rails 6.1 the dependency to rexml was removed but the default backend specification still remains.

In Ruby <= 2.7, the rexml library was included in the Ruby standard library. As such, it was still present and available even when not directly required. Starting with Ruby 3.0 however, rexml was converted into a bundled gem. As such, it is necessary to define it as a dependency in bundler (either explicitly or transitive via other dependencies). Now, if Redmine is installed with its test group (which is the default), rexml is installed as transitive dependency to rubocop and is thus available.

However, if bundler is configured with

bundle config --without test

on Ruby >= 3.0, rexml is not installed and is hidden by bundler, even if it's present as a bundled gem in Ruby. This results in ActiveSupport::XmlMini trying to load rexml fir its default backkend and failing.

We have two ways to resolve this:

we could add a strict rexml dependency to the Gemfile, effectively re-introducing the previous rails dependency:
```
gem "rexml", require: false
```
Alternatively, we could switch to a different backend. As Redmine already depends on nokogiri, we could thus switch the XmlMini backend to nokogiri in an initializer, e.g. config/initializers/30-redmine.rb:
```
ActiveSupport::XmlMini.backend = 'Nokogiri'
```
This likely has the added benefit of (much) faster XML parsing and generation.

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Updated by Go MAEDA almost 2 years ago

Holger Just wrote:

we could add a strict rexml dependency to the Gemfile, effectively re-introducing the previous rails dependency:
[...]

Alternatively, we could switch to a different backend. As Redmine already depends on nokogiri, we could thus switch the XmlMini backend to nokogiri in an initializer, e.g. config/initializers/30-redmine.rb:
[...]
This likely has the added benefit of (much) faster XML parsing and generation.

I would prefer the first approach. This is because the fix should be backported to 5.0-stable branch and delivered in 5.0.2, but I think switching a backend to Nokogiri is a somewhat big change for the maintenance release.

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Updated by Go MAEDA almost 2 years ago

Target version set to 5.0.2

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Updated by Go MAEDA almost 2 years ago

Related to Feature #34992: Ruby 3.0 support added

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Updated by Holger Just almost 2 years ago

Go MAEDA wrote:

I would prefer the first approach. This is because the fix should be backported to 5.0-stable branch and delivered in 5.0.2, but I think switching a backend to Nokogiri is a somewhat big change for the maintenance release.

In that case, I would be in favor of adding the rexml gem as a dependency for Ruby >= 3.0 on 5.0-stable only, i.e. to add the following patch in 5.0-stable:

diff --git a/Gemfile b/Gemfile
index cf7a8d78fa..29d639b9a7 100644
--- a/Gemfile
+++ b/Gemfile
@@ -14,6 +14,7 @@ gem 'marcel'
 gem "mail", "~> 2.7.1" 
 gem 'csv', '~> 3.2.0'
 gem 'nokogiri', (Gem.ruby_version < Gem::Version.new('2.6.0') ? '~> 1.12.5' : '~> 1.13.4')
+gem "rexml", require: false if Gem.ruby_version >= Gem::Version.new('3.0')
 gem 'i18n', '~> 1.10.0'
 gem "rbpdf", "~> 1.20.0" 
 gem 'addressable'

For trunk, we should instead opt to set the XmlMini backend to "Nokogiri" and get rid of rexml entirely. This avoids the usage of multiple different XML engines and the associated potential security issues due to different update-policies here.

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