MariaDB (and MySQL) is released in different versions with different behaviors. For backwards compatibility this can be managed with the sql_mode option.

Following you can find behavior differences which cannot be changed by this option. This can cause a regression in an existing application. There is no workaround available. The application needs to be adapted.

Queries with aggregated date types

For a database instance of MariaDB-10...

If you use webpacker in your Rails application, and you have completely disabled Sprockets, you might get the following error when trying to deploy: Rails assets manifest file not found. This happens inside the deploy:assets:backup_manifest task.

This task comes from capistrano-rails. It is build for Sprockets and does not work with Webpacker out of the box.

Solution

Configure capistrano-rails to work with Webpacker

Alternative

If you are using capistrano-rails, but...

Capistrano automatically logs each (successful) deployment into a file on your application servers.

It is located at the root of your server's project folder, i.e. the parent of releases and current, like so:

/var/www/your-project$ ls
current
log
releases
repo
revisions.log  <---  here
shared

Each line in that file contains the deployed branch, commit, release ID, and username (was read from the deploying user's machine):

$ tail -n3 revisions.log 
Branch master (at da45511bea63002ac2ff002d1692e09d0dd7cb88) deployed as rel...

General hints on the DOM

• the root of the DOM is document
• custom elements inherit from HTMLElement. They need a - (dash) in their name, e.g. <notification-box>.
• event listeners don't have event delegation à la .on('click', cssSelector, handler)

Comparison

Sometimes, due to git or other "accidents", important files get deleted or overwritten.

At a state when even Ctrl+Z doesn't work anymore, you maybe can rescue your files with RubyMines "Local History"-Feature!

To do this try the following:

• If the file got deleted, recreate a new empty file with the same name on the exact same place
• Open that file in the editor
• Go to RubyMine and click on VCS -> Local History -> Show History
• In the now open window, you should see all greater changes made to the File, even before it got deleted/temp...

Line-height and vertical-align are simple CSS properties. So simple that most of us are convinced to fully understand how they work and how to use them. But it’s not. They really are complex, maybe the hardest ones, as they have a major role in the creation of one of the less-known feature of CSS: inline formatting context.

For example, line-height can be set as a length or a unitless value 1, but the default is normal. OK, but what normal is? We often read that it is (or should be) 1, or maybe 1.2, even the CSS spec is unclear on that...

Inspecting the source of an email does not always reveal the plain HTML source, but some encoded byte mess. In order to inspect the HTML anyways, you can use a little trick:

While composing a message, select all (Ctrl + A), then navigate to Insert > HTML on the message window.

If you need to inspect a received message, hit "Reply" to turn it into composition mode.

git apply allows you to apply a diff onto your HEAD. Most often you can achieve the same result with a rebase & merge.

Example:

master                commit1 - commit3
feature-branch                \ commit2 - commit4

git checkout feature-branch
git reset --hard commit3
git diff ..commit4 | git apply

master                commit1 - commit3
feature-branch                          \ Unstaged commit 2 & 4

You can also [create a patch and apply it afterwards](https://makandracards.com/makandra/2521-git-how-to...

The goal is to get Jasmine specs running in a Rails project using Webpacker, with the browser based test runner. Should be easily adaptable to a pure Webpack setup.

Step 1: Install Jasmine

yarn add jasmine-core

Step 2: Add two separate packs

Since we do not want to mix Jasmine into our regular Javascript, we will create two additional packs. The first only contains Jasmine and the test runner. The second will contain our normal application code and the specs themselves.

We cannot...

If rspec hangs with no output and you dont get a backtrace neither with --backtrace nor by just killing it with crtl-c,
you can put the following in your spec/spec_helper.rb:

puts "rspec pid: #{Process.pid}"

trap 'USR1' do
  threads = Thread.list

  puts
  puts "=" * 80
  puts "Received USR1 signal; printing all #{threads.count} thread backtraces."

  threads.each do |thr|
    description = thr == Thread.main ? "Main thread" : thr.inspect
    puts
    puts "#{description} backtrace: "
    puts thr.backtrace.join("\n")
  end

...

In Ruby on Rails, all objects have a useful blank? method. It returns true for nil but also for empty strings or empty arrays. There is also a universal method present? which returns true for all values that are not blank?.

In JavaScript you need to roll your own implementation of blank? and present?.

If your application uses [Unpoly](...

The gem json fails to install for Ruby 2.5 if you use a version equal or below 1.8.3.

Run bundle update json --conservative to solve this issue.

The backtrace you will encounter looks like this:

Building native extensions. This could take a while...
ERROR:  Error installing json:
	ERROR: Failed to build gem native extension.

    current directory: /home/user/.rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/json-1.8.3/ext/json/ext/generator
/home/user/.rbenv/versions/2.5.3/bin/ruby -I /home/user/.rbenv/versions/2.5.3/lib/ruby/si...

Katapult was an endeavor to dramatically speed up starting a new Rails application. However, it turned out to save less time than expected, while requiring more time for maintenance than anticipated. Since its benefits fell too low, we have decided to not continue developing Katapult.

You can still use Katapult for generating ready-to-run applications with model CRUD, authentication and all of Katapult's features, but the rapid development of the web will quickly render the generated code antiquated. Nevertheless, its architecture may remai...

When you need to check a value for presence, don't rely on JavaScript since it considers 0 or "0" false. Also don't rely on LoDash's _.isEmpty:

if ('0') { ... } // false
if (0) { ... } // false

^
if (!.isEmpty('0')) { ... } // true (= good)
if (!.isEmpty(0)) { ... } // false (= not good)

This is because isEmpty it is only meant for objects with a length.

While the name implies that it's meant only for collections, you probably still want something like isBlank or `is...

Rails guide that covers PostgreSQL-specific column types and usages for Active Record.

You should especially keep in mind the special datatypes that PostgreSQL offers. \
Types like json and array take away a lot of the pain that you had on MySQL projects.

Example use cases for array are tags or storing foreign keys (instead of a join model). You can even index them.

Travis changed their default distribution from Ubuntu 14.04 (trusty) to 16.04 (precise). This might break your test setup for new builds.

You can solve this issue by freezing your test distribution in the .travis.yml to Ubuntu 14.04 until you have the time to solve all the issues you will have in 16.04:

dist: trusty

Error details

Here are few indicators that you ran into this issue:

Connection to the PostgreSQL database does not work anymore

Your travis-ci builds might have started failing on the usual

psql -c...

The issue in this card can occur if the node_modules directory is checked into your Git repository. We usually recommend to exclude node_modules from version control.

In any case you should document which version of node to use in your project in a .nvmrc file.

I saw a strange behaviour after we introduced webpack in one of our projects and finally found out the reason: The person who committed the files used a node version that is older than mine.

Every time I wanted to run my rai...

Cucumber up to version 2 had a neat feature called Step Argument Transforms which was dropped in favor of Cucumber 3 ParameterTypes. While I strongly encourage you to drop your legacy Transforms when upgrading to Cucumber 3, it might not always be possible due to their different design.
This is a guide on how to keep the exact same functionality of your old Transforms while writing them in the style of new `Paramet...

When installing a gem you can use version comparators like >= or ~>. That way it is possible to fetch the latest version of Bundler 1 with this command:

gem install bundler -v '~>1'

How to install bundler for Ruby < 2.3 is a common usecase where you might need Bundler 1.

If you get requests with values for formats like this:

{:locale=>[:de], :formats=>["../../../../../../../../../../etc/services{{"], :variants=>[], :handlers=>[:erb, :builder, :raw, :ruby, :coffee, :haml]}

or fails like this:

Invalid query parameters: invalid %-encoding (../../../../../../../../../etc/passwd%%0000.html)

Someone tries to exploit CVE-2019-5418.
If you use the latest Rails (or latest Rails LTS) you're...