PHP Composer update "cannot allocate memory" error (using Laravel 4)

I have faced the same issue. I am on a AWS Free Microinstance which has less memory. I always try one of the below options and it always works (Before all this please check if you have the latest version of composer installed)

sudo php -dmemory_limit=750M composer.phar update

or remove the contents of the vendor folder and try composer update.

sudo rm -rf vendor
sudo php -dmemory_limit=750M composer.phar update --no-scripts --prefer-dist
sudo php artisan --dump-autoload

The second option tries to update all the components, if there is no update, it picks up the package from the cache else picks up from the dist

Note: Please change the memory limit as per your choice.

or

Create a swap partition and try. Swap partition is the portion of the hard drive that linux uses as virtual memory when it runs out of physical memory. It's similar to the windows swap file only instead of using an actual file, linux uses a partition on the hard drive instead.

Hope this helps

A bit old but just in case someone new is looking for a solution, updating your PHP version can fix the issue.

Also you should be committing your composer.lock file and doing a composer install on a production environment which is less resource intensive.

More details here: https://github.com/composer/composer/issues/1898#issuecomment-23453850

Looks like you runs out of swap memory, try this

/bin/dd if=/dev/zero of=/var/swap.1 bs=1M count=1024
/sbin/mkswap /var/swap.1
/sbin/swapon /var/swap.1

as mentioned by @BlackBurn027 on comments below, this solution was described in here

As composer troubleshooting guide here This could be happening because the VPS runs out of memory and has no Swap space enabled.

free -m

To enable the swap you can use for example:

sudo /bin/dd if=/dev/zero of=/var/swap.1 bs=1M count=1024
sudo /sbin/mkswap /var/swap.1
sudo /sbin/swapon /var/swap.1

Or if above not worked then you can try create a swap file

sudo fallocate -l 2G /swapfile
sudo chmod 600 /swapfile
sudo mkswap /swapfile
sudo swapon /swapfile