Re-add old blog posts from Astro

source/_posts/minimum-core-version.md

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+---
+title: How to Define a Minimum Drupal Core Version
+date: 2015-04-03
+excerpt: How to define a minimum Drupal core version for your module or theme.
+tags:
+    - drupal
+    - drupal-7
+    - drupal-planet
+meta:
+    og:
+        title: 'How to Define a Minimum Drupal Core Version'
+        excerpt: 'How to define a minimum Drupal core version for your module or theme.'
+        type: article
+---
+
+This week, my first code patch was
+[committed to Drupal core](https://www.drupal.org/node/2394517#comment-9773143).
+The patch adds the `user_has_role()` function to the user module, to simplify
+the way to check whether a user in Drupal has been assigned a specific role.
+This is something that I normally write a custom function for each project, but
+it's now available in Drupal core as of
+[7.36](https://www.drupal.org/drupal-7.36-release-notes).
+
+But what if someone is using a core version less than 7.36 and tries using the
+function? The site would return an error because that function wouldn't exist.
+
+If you're building a new Drupal site, then I'd assume that you're using a latest
+version of core, or you have the opportunity to update it when needed. But what
+if you're writing a contrib module? How can you be sure that the correct minimum
+version of core?
+
+## Setting Dependencies
+
+What I'm going to be doing for my contrib projects is defining a minimum version
+of Drupal core that the module is compatible with. If this dependency isn't met,
+the module won't be able to be enabled. This is done within your module's .info
+file.
+
+### Adding a Simple Dependency
+
+You can define a simple dependency for your module by adding a line this this to
+your project's .info file:
+
+```bash
+dependencies[] = views
+```
+
+This would make your module dependant on having the
+[Views](https://www.drupal.org/project/views) module present and enabled, which
+you'd need if you were including views as part of your module, for example.
+
+### Adding a Complex Dependency
+
+In the previous example, our module would enable if _any_ version of Views was
+enabled, but we need to specify a specific version. We can do this by including
+version numbers within the dependencies field in the following format:
+
+```bash
+dependencies[] = modulename (major.minor)
+```
+
+This can be a for a specific module release or a branch name:
+
+```bash
+dependencies[] = modulename (1.0)
+dependencies[] = modulename (1.x)
+```
+
+We can also use the following as part of the field for extra granularity:
+
+- = or == equals (this is the default)
+- > greater than
+- < lesser than
+- > = greater than or equal to
+- <= lesser than or equal to
+- != not equal to
+
+In the original scenario, we want to specify that the module can only be enabled
+on Drupal core 7.36 or later. To do this, we can use the "greater than or equal
+to" option.
+
+```ini
+dependencies[] = system (>=7.36)
+```
+
+Because we need to check for Drupal's core version, we're using the system
+module as the dependency and specifying that it needs to be either equal to or
+greater than 7.36. If this dependency is not met, e.g. Drupal 7.35 is being
+used, then the module cannot be enabled rather than showing a function not found
+error for `user_has_role()` when it is called.
+
+![A screenshot of the modules page showing System as a dependency for a custom module.](/images/blog/minimum-drupal-version-d7.png)
+
+## External Links
+
+- [Writing module .info files (Drupal 7.x)](https://www.drupal.org/node/542202#dependencies)