git-flow, DTAP & semver

Using git-flow in a DTAP environment.

I’m a big fan of Git and I tend to use git-flow in most of my projects. A lot of people don’t like it, because it can be very tedious, but even if you only use develop and master branches, you’re already benefiting from it.

If you have multiple environments to deploy to, you can leverage git-flow logic to automatically deploy to these environments (in our case DTAP: development, testing, acceptance and production). Using a CI/CD server (like Gilab CI), we can auto deploy to specific environments when code gets pushed to the server.


Let’s have a look at some definitions first.

  • develop
    • The main development branch
    • Ideally this branch only contains merge commits
  • master
    • This branch represents code in production
    • This branch must only contain merge commits
  • feature/*
    • New development is done in a feature branch
    • This branch is started from develop and will be merged back into develop when it’s done
    • By using a feature branch, you can leverage merge request
  • release/*
    • This branch sits between develop and master (getting ready for a new production release)
    • This branch is short-lived and totally optional
  • hotfix/*
    • When something is wrong in production, a fix can be produced via a hotfix branch
    • This branch is started from master and will be merged into both master and develop


  • Development: local development
  • Testing: beta server
  • Acceptance: alpha server
  • Production: live

Semantic versioning

Semantic versioning is a way of applying version to your software so it’s clear what impact it may have. As described on the homepage (

Given a version number MAJOR.MINOR.PATCH, increment the:

  • MAJOR version when you make incompatible API changes,
  • MINOR version when you add functionality in a backwards-compatible manner, and
  • PATCH version when you make backwards-compatible bug fixes.

Additional labels for pre-release and build metadata are available as extensions to the MAJOR.MINOR.PATCH format.

When applied to git-flow, version are added in the form of git tags, and (for now) only the master branch receives tags.

When you merge develop or a release branch into master, you add a MAJOR.MINOR tag to it (only increment the MAJOR number is the change is big enough). When you merge a hotfix branch into master, increase the PATCH version.

In practice

Now we can configure our CI/CD system to start when we push code to a specific branch. In the Gitlab CI case, it is possible to limit jobs to branches with “only”.

  • develop: auto deploy to Testing
  • release/*: auto deploy to Acceptance
  • master: auto deploy to Production

Tag based CI/CD

You could even limit job execution by using tags. Instead of starting jobs when you push code to a specific branch, you could let developers push to specific branches and kickstart a job by tagging it accordingly (which can be used to throttle builds and/or limit target environments).

Semantic versioning allows additional labels for pre-release and build metadata which we can leverage (1.0.0-alpha < 1.0.0-alpha.1 < 1.0.0-alpha.beta < 1.0.0-beta < 1.0.0-beta.2 < 1.0.0-beta.11 < 1.0.0-rc.1 < 1.0.0).

If you have extra environments (i.e. Education, Backup, Staging, etc…) you now can use even more pre-release tags:

Bonus points

Since we’re using semantic versioning and a build system, we can auto append build metadata to our version numbers. In the case of Gitlab CI, you can write a file containing a version number in the form of “1.0.0-rc.2+15” by using the git tag and the CI_JOB_ID variable.

Sort Composer packages for your git merging pleasure

A lot of git merge conflicts occur when multiple developers add lines to the end of a file/list. This also happens in composer.json, AppKernel.php, translation files, config/application.config.php, CSS files, CHANGELOG, etc…

diff --cc composer.json
index 62e875e,0c526d8..0000000
--- a/composer.json
+++ b/composer.json
@@@ -10,6 -10,6 +10,10 @@@
      "require": {
          "ramsey/uuid": "^3.0",
          "roave/security-advisories": "dev-master",
++<<<<<<< HEAD
 +        "beberlei/assert": "^2.3@dev"
+         "miljar/php-exif": "dev-master"
++>>>>>>> exif

A nice solution is that every developer adds lines or blocks to random places in a list or a file, but a better solution is to sort these lines (especially for lists like composer.json, translation files, etc…). This way you insert new lines in “random” places, keeping it clear for everyone how things are added.

diff --git a/changelog.rst b/changelog.rst
index d9db648..886b168 100644
--- a/changelog.rst
+++ b/changelog.rst
@@ -19,7 +19,9 @@ June, 2015
 New Documentation

+* `#5423 <>`_ [Security] add & update doc entries on AbstractVoter implementation (Inoryy, javiereguiluz)
 * `#5401 <>`_ Added some more docs about the remember me feature (WouterJ)
+* `#5384 <>`_ Added information about the new date handling in the comparison constraints and Range (webmozart, javiereguiluz)
 * `#5382 <>`_ Added support for standard Forwarded header (tony-co, javiereguiluz)
 * `#5361 <>`_ Document security.switch_user event (Rvanlaak)

Full diff on Github

Some tools and hacks that assist you with this:

Something that does not work for composer.json, but something I highly recommend, is to add trailing commas in PHP arrays and to not align code (see the blogpost by Made With Love about “How clean are your diffs?”). This eases up merging too!

Happy merging!