Month: February 2017

Moving files with commit history from one git repository to another

I’ve searched for this before, and I’m sure I’ll do that again (although the need is not that frequent), so here it goes.  It is possible to move files from one git repository to another, preserving commit history.  The following links provide a few examples of how to do this:

Basically, you need git filter-branch command, usually with the –subdirectory-filter parameter.

An example of where it is useful would be the extraction of some code from a project you have into a shared library or a simple plugin.

Modular CSS : Block, Element, Modifier

I don’t do a lot of front-end work these days, but I am genuinely interested in approaches that help build modular systems, especially when the subject is something as messy and as context-dependent as CSS.

Recently, I came across the Block-Element-Modifier approach, aka BEM, which I find interesting.

If you’re not familiar with BEM, it’s a naming methodology that provides a rather strict way to arrange CSS classes into independent components. It stands for Block Element Modifier and a common one looks like this:

.block {}
.block__element {}
.block--modifier {}
.block__element--modifier {}

The principles are simple — a Block represents an object (a person, a login form, a menu), an Element is a component within the block that performs a particular function (a hand, a login button, a menu item) and a Modifier is how we represent the variations of a block or an element (a female person, a condensed login form with hidden labels, a menu modified to look differently in the context of a footer).

This follow-up article provides more details and examples.

Composer require inline alias

Here’s a feature of composer that I didn’t know about until a few days ago – require inline alias.  Here’s the example from the documentation:

{
    "repositories": [
        {
            "type": "vcs",
            "url": "https://github.com/you/monolog"
        }
    ],
    "require": {
        "symfony/monolog-bundle": "2.0",
        "monolog/monolog": "dev-bugfix as 1.0.x-dev"
    }
}

This is super useful when you have dependencies in your project that require a particular version of a third-party library or plugin, and you want to try a branch of that library or plugin. Switching to the branch alias doesn’t solve the problem, as everything that has version constraints on that requirement, will complain. With inline alias, you can alias a particular branch of the dependency as a particular version.

With inline alias, composer will fetch the branch that you want, but will assume that that branch works as a particular version that you specify, and thus satisfy all the other dependencies that require that particular version.

In my particular case, I was working on the CakePHP-based application, which was using a few CakePHP plugins (installed via composer).  Those plugins require CakePHP v3+.  I wanted to test a branch of CakePHP which had a particular fix I was interested in, but without disabling all the plugins.  Switching my application’s composer to require a branch dissatisfied all the plugins, as now composer didn’t know if the branch that I am requiring is of the CakePHP v3 or not.  Aliasing the branch to v3.4.1 (current stable version at the time) worked like a charm.