Composer installation fails with "failed to open stream: Too many open files"

Question

When trying to install Magento 2 Open Source with the following command, I get the following error. I've already upped my maxfiles to kingdom come, without any positive effect. How do I fix this?

Error

  [ErrorException]
  fopen(/Users/myuser/.composer/cache/files/magento/theme-frontend-luma/873ad0c55501fa7ae548f048b69ca7af8c2a3bd8.zip): failed to open stream: Too many open files

Current maxfiles

$ launchctl limit maxfiles
        maxfiles    9000000        9000000

Composer version

$ composer --version
Composer version 1.10.7 2020-06-03 10:03:56

OS

I'm on macOS 10.15.4

Full output

$ composer create-project --repository-url=https://repo.magento.com/ magento/project-community-edition magento-composer
    1/10:       http://repo.packagist.org/p/provider-latest$e90d775d6b3ac421d2e2583dac3f23dbf6378a1eb194d8e3a6ee06b8870ccce8.json
    2/10:       http://repo.packagist.org/p/provider-2019-10$b3a05d79df4089bea2f5fe34d8310a4782aecba55eed265ae5294c4f778a84b3.json
    3/10:       http://repo.packagist.org/p/provider-2015$2386737641788c1c4028f3e4ef660d2b943225ec9ef628f950b78318ab85aae7.json
    4/10:       http://repo.packagist.org/p/provider-2019-07$684cc425814c8fcd3dd38f426d7386883638dac951eb0680c149f6d68c47d9df.json
    5/10:       http://repo.packagist.org/p/provider-2020-04$9b2361cb6ae781889cd664f1d71fcab5de8873e2cbc8f0d812fc52bbe8174689.json
    6/10:       http://repo.packagist.org/p/provider-2020-01$b5bfc61ac4692d85e9adada04b7aa0e7852d899220d93c8365d1c902eb36b70f.json
    7/10:       http://repo.packagist.org/p/provider-2019$2bc08951c25c11eaafd69eefef138011cea4fd0ece31d50f47a57913f3531b16.json
    8/10:       http://repo.packagist.org/p/provider-2016$c40345634080e37ff5671a70bc06d3ca8b289c28c96fbda5728c1e56988359fe.json
    9/10:       http://repo.packagist.org/p/provider-2018$19577c7b34ae6fbb1eb8957653ecdba16ebd7a8dec7ba5727c875d89c1d83bad.json
    10/10:      http://repo.packagist.org/p/provider-2017$502291b972280e346bdaf8bff71f8a62e2647e0b6860a9e25513b5f20564fe61.json
    Finished: success: 10, skipped: 0, failure: 0, total: 10
    1/10:       http://repo.packagist.org/p/provider-latest$e90d775d6b3ac421d2e2583dac3f23dbf6378a1eb194d8e3a6ee06b8870ccce8.json
    2/10:       http://repo.packagist.org/p/provider-2019-07$684cc425814c8fcd3dd38f426d7386883638dac951eb0680c149f6d68c47d9df.json
    3/10:       http://repo.packagist.org/p/provider-2019-10$b3a05d79df4089bea2f5fe34d8310a4782aecba55eed265ae5294c4f778a84b3.json
    4/10:       http://repo.packagist.org/p/provider-2020-01$b5bfc61ac4692d85e9adada04b7aa0e7852d899220d93c8365d1c902eb36b70f.json
    5/10:       http://repo.packagist.org/p/provider-2015$2386737641788c1c4028f3e4ef660d2b943225ec9ef628f950b78318ab85aae7.json
    6/10:       http://repo.packagist.org/p/provider-2016$c40345634080e37ff5671a70bc06d3ca8b289c28c96fbda5728c1e56988359fe.json
    7/10:       http://repo.packagist.org/p/provider-2020-04$9b2361cb6ae781889cd664f1d71fcab5de8873e2cbc8f0d812fc52bbe8174689.json
    8/10:       http://repo.packagist.org/p/provider-2019$2bc08951c25c11eaafd69eefef138011cea4fd0ece31d50f47a57913f3531b16.json
    9/10:       http://repo.packagist.org/p/provider-2018$19577c7b34ae6fbb1eb8957653ecdba16ebd7a8dec7ba5727c875d89c1d83bad.json
    10/10:      http://repo.packagist.org/p/provider-2017$502291b972280e346bdaf8bff71f8a62e2647e0b6860a9e25513b5f20564fe61.json
    Finished: success: 10, skipped: 0, failure: 0, total: 10
Creating a "magento/project-community-edition" project at "./magento-composer"
Installing magento/project-community-edition (2.3.5-p1)
  - Installing magento/project-community-edition (2.3.5-p1): Loading from cache
Created project in /Users/myuser/Sites/Research/magento-composer
    1/10:       http://repo.packagist.org/p/provider-2019-07$684cc425814c8fcd3dd38f426d7386883638dac951eb0680c149f6d68c47d9df.json
    2/10:       http://repo.packagist.org/p/provider-latest$e90d775d6b3ac421d2e2583dac3f23dbf6378a1eb194d8e3a6ee06b8870ccce8.json
    3/10:       http://repo.packagist.org/p/provider-2015$2386737641788c1c4028f3e4ef660d2b943225ec9ef628f950b78318ab85aae7.json
    4/10:       http://repo.packagist.org/p/provider-2019-10$b3a05d79df4089bea2f5fe34d8310a4782aecba55eed265ae5294c4f778a84b3.json
    5/10:       http://repo.packagist.org/p/provider-2019$2bc08951c25c11eaafd69eefef138011cea4fd0ece31d50f47a57913f3531b16.json
    6/10:       http://repo.packagist.org/p/provider-2016$c40345634080e37ff5671a70bc06d3ca8b289c28c96fbda5728c1e56988359fe.json
    7/10:       http://repo.packagist.org/p/provider-2020-01$b5bfc61ac4692d85e9adada04b7aa0e7852d899220d93c8365d1c902eb36b70f.json
    8/10:       http://repo.packagist.org/p/provider-2020-04$9b2361cb6ae781889cd664f1d71fcab5de8873e2cbc8f0d812fc52bbe8174689.json
    9/10:       http://repo.packagist.org/p/provider-2017$502291b972280e346bdaf8bff71f8a62e2647e0b6860a9e25513b5f20564fe61.json
    10/10:      http://repo.packagist.org/p/provider-2018$19577c7b34ae6fbb1eb8957653ecdba16ebd7a8dec7ba5727c875d89c1d83bad.json
    Finished: success: 10, skipped: 0, failure: 0, total: 10
Loading composer repositories with package information
Updating dependencies (including require-dev)


  [ErrorException]
  fopen(/Users/myuser/.composer/cache/files/magento/theme-frontend-luma/873ad0c55501fa7ae548f048b69ca7af8c2a3bd8.zip): failed to open stream: Too many open files

Answer 1

You can up your system's file open limit on Linux or Max OS with the following:

ulimit -n 10000

This should help with the composer issue.