tl;dr

git checkout is the swiss army of git commands. If you prefer a semantically more meaningful command for restoring tasks, use git restore instead.

With this command you can ...

• ... do unstaging - git restore --staged
• ... discard staged changes - git restore --staged --worktree
• ... discard unstaged changes - git restore
• ... restore deleted files - git restore
• ... restore historic versions - git restore --source
• ... recreate merge conflicts - git restore --merge
• ... specifiy...

Use case

You have uncommited changes (you can always check by using git status), which you want to discard.

Context

Now there are several options to discard these depending on your exact situation.
The headlines will differentiate the cases whether the files are staged or unstaged.

1. Staged and unstaged changes
2. [Staged changes](https://makandracards.com/makandra/516559-git-commands-to-discard-local-changes#s...

tl;dr

In RubyMine you can use find and replace with capture groups (.*?) and backreferences $1 (if you have several groups: $[Capture-Group ID]).
Named captures (?<text>.*) are also supported.

Examples

Replace double quotes with single quotes

If you want to replace double quotes with single quotes, replacing every " with a ' is prone to errors. Regular expressions can help you out here.

1. Open find and replace
2. Activate the regex mode (click on the .* icon next to the "find" field).
3. Fill in f...

The robots.txt file and <meta name="robots"> HTML tag can be used to control the behavior of search engine crawlers. Both have different effects.

robots.txt

Marking a URL path as "disallowed" in robots.txt tells crawlers to not access that path.

robots.txt is not a guarantee for exclusion from search engine results.

A "disallowed" URL might be known from an external link, and can still be displayed for a matching search.
Example: even if /admin is disallowed in robots.txt, `/admin/som...

A memory leak is an unintentional, uncontrolled, and unending increase in memory usage. No matter how small, eventually, a leak will cause your process to run out of memory and crash.

If you have learned about a memory leak, looking at the number of Ruby objects by type can help you track it down:

> pp ObjectSpace.count_objects
{:TOTAL=>77855,
 :FREE=>4526,
 :T_OBJECT=>373,
 :T_CLASS=>708,
 :T_MODULE=>44,
 :T_FLOAT=>4,
 :T_STRING=>65685,
 :T_REGEXP=>137,
 :T_ARRAY=>984,
 :T_HASH=>87,
 :T_STRUCT=>12,
 :T_BIGNUM=>2,
 :T_FILE=>3,
 :T_D...

For Rails models where only one of multiple attributes may be filled out at the same time, there is no built-in validation.

I've seen different solutions in the wild, each with different downsides:

• Private method referenced via validate: works, but is barely portable and clutters the model.
• Multiple presence validations with "if other is blank" each: looks pretty, but is incorrect as it allows both values to be filled in; also the error messages for a blank record are misleading.

Here is a third option: Write a custom validator to ...

Note

Use yarn dedupe in Yarn v2+: https://yarnpkg.com/cli/dedupe

This package only works with Yarn v1. Yarn v2 supports package deduplication natively!

A duplicate package is when two dependencies are resolved to a different version, even when a single version matches the range specified in the dependencies. See the Deduplication strategies section for a few examples.

Yarn is stupid, so it can happen that there are several version of the same package in your bundle, although one would fulf...

Recently we detected a memory leak in one of our applications. Hunting it down, we found that the memory leak was located in Rails' #prepend_view_path. It occurs when the instance method prepend_view_path is called in each request, which is a common thing in a multi-tenant application.

On top of leaking memory, it also causes a performance hit, since templates rendered using the prepended view path will not be cached and compiled anew on each request.

This is not a new memory leak. It was [first reported in in 2014](https://github.com/...

The linked content includes a few design patterns implemented with Ruby on Rails.

What is the card indented to achieve?

• You can use the pattern names for code reviews, so all parties know with only a few words which change is requested. Example: "Please use a form object here"
• You can learn about new code patterns
• You should read the sections "Advantages of using design patterns" and "Disadvantages of using design patterns in a wrong way", since design patterns do not replace good code

Included Design Patterns: Service, Value objec...

These are the results of the "personal tech stack survey". I've included only the most popular mentions, maybe it can help you find one or two useful tools for your own usage.

Desktop environment

pie title Desktop environment
    "Gnome" : 16
    "i3": 2
    "sway": 2
    "awesome": 1
    "bspwm": 1
    "mate": 1
    "xfce": 1

Gnome dominates (unsuprising, it's the Ubuntu default), but quite a few people use tiling window managers, most popular i3 and the mostly i3-compatible [sway](https://swaywm....

You can use the code below to check whether the browser can make connections to the current site:

await isOnline() // resolves to true or false

The code

The isOnline() function below checks if you can make real requests by re-fetching your site's favicon. If the favicon cannot be downloaded within 6 seconds, it considers your connection to be offline.

async function isOnline({ path, timeout } = {}) {
  if (!navigator.onLine) return false

  path ||= document.querySelect...

I recently wanted to add a model for address information but also wanted to add a unique index to those fields that is case-insensitive.
The model looked like this:

create_table :shop_locations do |t|
  t.string :street
  t.string :house_number
  t.string :zip_code
  t.string :city
  t.belongs_to :shop
end

But how to solve the uniqueness problem?

Another day, another undocumented Rails feature!

This time, it’s that ActiveRecord::Base.connection.add_index supports an undocumented option to pass a string argument as the v...

It might sometimes be useful to check whether your Rails application accesses the file system unnecessarily, for example if your file system access is slow because it goes over the network.

The culprit might be a library like carrierwave that checks file existence or modification times, whereas your application could determine all this from your database.

Introducing strace

One option it to use strace for this, which logs all system calls performed by a process.

To do this, start your rails server using something like

DISA...

Testing file download links in an end-to-end test can be painful, especially with Selenium.

The attached download_helpers.rb provides a download_link method for your Capybara tests. It returns a hash describing the download's response:

details = download_link('Download report')
details[:disposition]  # => 'attachment' or 'inline'
details[:filename]     # => 'report.txt'
details[:text]         # => file content as string
details[:content_type] # => 'text/plain'

Features

Compared to [other approaches](...

While verifying doubles in RSpec is a good default, it is limited in the amount of methods it actually is able to verify.

The background is that RSpec can't verify dynamically defined methods, which is a known issue for the usage of helper_method and also the reason why [RSpec >= 3.6](http://rspec.info/blog/2017/05/rspec-3-6-has-been-rel...

Code quality can be measured in four levels:

0. (Working code)
1. Reliable code (minimum)
2. Readable code (ok for short-lived code)
3. Changeable code (standard level)

The code quality of a project directly impacts its maintainability.

Generally you should aim for level 3. If the code will stay for less than a few months, it may stay at level 2. Never go below level 1.

0. Working code

You have implemented that feature and it works. Congrats! You have reached level zero, which means three levels of code quality lie ahead.

First, m...

tl;dr
You can use attribute? as shorthanded version of attribute.present?, except for numeric attributes and associations.

Technical Details

attribute? is generated for all attributes and not only for boolean attributes.

These methods are using #query_attribute under the hood. For more details you can see ActiveRecord::AttributeMethods::Query.

In most circumstances query_attribute is working like attribute.present?. If your attribute is responding to :zero? then you have to be aware that `query_attri...

When you need information about a gem (like version(s) or install path(s)), you can use the gem binary from the command line, or the Gem API inside a ruby process at runtime.

gem binary (in a terminal)

You can get some information about a gem by running gem info <gem name> in your terminal.

Example:

$ gem info irb

*** LOCAL GEMS ***

irb (1.4.1, 1.3.5)
    Author: Keiju ISHITSUKA
    Homepage: https://github.com/ruby/irb
    Licenses: Ruby, BSD-2-Clause
    Installed at (1.4.1): /home/arne/.rbenv/versions/3.0.3/lib/ruby/g...

Redis.current will be removed without replacement in redis-rb 5.0.
Version 4.6.0 adds deprecation warnings for Redis.current and Redis.current=:

`Redis.current=` is deprecated and will be removed in 5.0.

If your application still uses Redis.current, you can only fix it by no longer using it. Here is how.

Redis.new when you need it

You can easily instantiate a Redis client when you need it.

There is probably already a constant like REDIS_URL that you use to configure Sidekiq or similar. So just use that one.

``...

While we are used to run our JavaScript tests on a test page within our Browser, it's also possible to run them on the command line with NodeJS. I think that's actually the most common way to run JS tests.

Given a Vue project that uses Jest (via vue-cli-service) with the following package.json:

{
  "scripts": {
    "test": "vue-cli-service test:unit --testMatch='**/tests/**/*.test.js' --watch"
  },
}

This allows us to run J...

We use foreman to start all necessary processes for an application, which are declared in a Procfile. This is very convenient, but the outputs of all processes get merged together. Especially while debugging you might not want other processes to flood your screen with their log messages.

The following setup allows you to start Terminator in a split view with the Rails server running in the left pane and all remaining processes running via foreman in the right pane. It was heavily inspired by [this card](https://makandracards.com/makandr...

Building application assets with esbuild is the new way to do it, and it's great, especially in combination with Sprockets (or Propshaft on Rails 7).
You might be missing some convenience features, though.

Here we cover one specific issue:
Once you have started your development Rails server and esbuild with the --watch option (if you used jsbundling-rails to set up, you probably use bin/dev), esbuild will recompile your assets upon change, but build errors will only be printed to the terminal. Your application won't complain about them ...

Attaching files to a field that is handled by Carrierwave uploaders (or maybe any other attachment solution for Rails) in tests allows different approaches. Here is a short summary of the most common methods.

You might also be interested in this card if you see the following error in your test environment:

CarrierWave::FormNotMultipart:
You tried to assign a String or a Pathname to an uploader, for security reasons, this is not allowed.
If this is a file upload, please check that your upload form is multipart encoded.

Factor...

When Capybara locates elements in the DOM, by default it allows only accessing visible elements -- when you are using a driver that supports it (e.g. Selenium, not the default Rack::Test driver).

Consider the following HTML:

<div class="test1">One<div>
<div class="test2">Two</div>

With some CSS:

.test1 { display: block }
.test2 { display: none }

We will be using Capybara's find below, but this applies to any Capybara finder methods.

Default: visible: :visible

As described above, by default Capybara finds ...