Can't install composer - the json extension is missing

Question

I'm trying to install composer on my Ubuntu 13.10 machine but the following error occurs:

Some settings on your machine make Composer unable to work properly.
Make sure that you fix the issues listed below and run this script again:

The json extension is missing.
Install it or recompile php without --disable-json

php --version gives me PHP 5.5.3-1ubuntu2 (cli) so I think it should have the json extension installed.

Solution

just install the module:

sudo apt-get install php5-json

---

EDIT - Reason:

See Heanzo Beanzo Comment:

It has been removed in recent packages due to a license conflict see bug on php.net.

Comments

[Nikos Grigoriadis]

That works thanks. But isn't the json extension supposed to be bundled and compiled into PHP by default?

[Rufinus]

the core of php is rather small, all is grouped in modules. if you compile from source, many of this modules (like json) are selected by default. but it seems the package maintainer want to give the user more control over what he wants to install. this is good in most cases.

[Hannes Schneidermayer]

It has been removed in recent packages due to a license conflict (see bugs.php.net/bug.php?id=63520).

[rickfoosusa]

If php-json were a dependency of php-common, everyone would have installed it while upgrading to 13.10..It wasted enough of my time to file a bug: bugs.launchpad.net/ubuntu/+source/ubiquity/+bug/1280030

[Rufinus]

and the whole reason why.. cause he thinks he is funny... youtube.com/watch?v=-hCimLnIsDA

[Syed Priom]

How do you verify it's installed or not?