composer.lock file is causing dependency errors regarding php version

[sinfuljosh]

A clean attempt to create project following your install steps on a php 5.6.36 env still were throwing the following errors.

  Problem 1
    - Installation request for doctrine/annotations v1.6.0 -> satisfiable by doctrine/annotations[v1.6.0].
    - doctrine/annotations v1.6.0 requires php ^7.1 -> your PHP version (5.6.36) does not satisfy that requirement.
  Problem 2
    - Installation request for swiftmailer/swiftmailer v6.0.2 -> satisfiable by swiftmailer/swiftmailer[v6.0.2].
    - swiftmailer/swiftmailer v6.0.2 requires php >=7.0.0 -> your PHP version (5.6.36) does not satisfy that requirement.
  Problem 3
    - Installation request for symfony/console v4.0.8 -> satisfiable by symfony/console[v4.0.8].
    - symfony/console v4.0.8 requires php ^7.1.3 -> your PHP version (5.6.36) does not satisfy that requirement.
  Problem 4
    - Installation request for symfony/event-dispatcher v4.0.8 -> satisfiable by symfony/event-dispatcher[v4.0.8].
    - symfony/event-dispatcher v4.0.8 requires php ^7.1.3 -> your PHP version (5.6.36) does not satisfy that requirement.
  Problem 5
    - Installation request for symfony/filesystem v4.0.8 -> satisfiable by symfony/filesystem[v4.0.8].
    - symfony/filesystem v4.0.8 requires php ^7.1.3 -> your PHP version (5.6.36) does not satisfy that requirement.
  Problem 6
    - Installation request for symfony/finder v4.0.8 -> satisfiable by symfony/finder[v4.0.8].
    - symfony/finder v4.0.8 requires php ^7.1.3 -> your PHP version (5.6.36) does not satisfy that requirement.
  Problem 7
    - Installation request for symfony/options-resolver v4.0.8 -> satisfiable by symfony/options-resolver[v4.0.8].
    - symfony/options-resolver v4.0.8 requires php ^7.1.3 -> your PHP version (5.6.36) does not satisfy that requirement.
  Problem 8
    - Installation request for symfony/process v4.0.8 -> satisfiable by symfony/process[v4.0.8].
    - symfony/process v4.0.8 requires php ^7.1.3 -> your PHP version (5.6.36) does not satisfy that requirement.
  Problem 9
    - Installation request for symfony/stopwatch v4.0.8 -> satisfiable by symfony/stopwatch[v4.0.8].
    - symfony/stopwatch v4.0.8 requires php ^7.1.3 -> your PHP version (5.6.36) does not satisfy that requirement.
  Problem 10
    - Installation request for doctrine/instantiator 1.1.0 -> satisfiable by doctrine/instantiator[1.1.0].
    - doctrine/instantiator 1.1.0 requires php ^7.1 -> your PHP version (5.6.36) does not satisfy that requirement.
  Problem 11
    - Installation request for phpdocumentor/reflection-docblock 4.3.0 -> satisfiable by phpdocumentor/reflection-docblock[4.3.0].
    - phpdocumentor/reflection-docblock 4.3.0 requires php ^7.0 -> your PHP version (5.6.36) does not satisfy that requirement.
  Problem 12
    - Installation request for phpunit/php-code-coverage 6.0.4 -> satisfiable by phpunit/php-code-coverage[6.0.4].
    - phpunit/php-code-coverage 6.0.4 requires php ^7.1 -> your PHP version (5.6.36) does not satisfy that requirement.
  Problem 13
    - Installation request for phpunit/php-timer 2.0.0 -> satisfiable by phpunit/php-timer[2.0.0].
    - phpunit/php-timer 2.0.0 requires php ^7.1 -> your PHP version (5.6.36) does not satisfy that requirement.
  Problem 14
    - Installation request for phpunit/php-token-stream 3.0.0 -> satisfiable by phpunit/php-token-stream[3.0.0].
    - phpunit/php-token-stream 3.0.0 requires php ^7.1 -> your PHP version (5.6.36) does not satisfy that requirement.
  Problem 15
    - Installation request for phpunit/phpunit 7.1.4 -> satisfiable by phpunit/phpunit[7.1.4].
    - phpunit/phpunit 7.1.4 requires php ^7.1 -> your PHP version (5.6.36) does not satisfy that requirement.
  Problem 16
    - Installation request for phpunit/phpunit-mock-objects 6.1.1 -> satisfiable by phpunit/phpunit-mock-objects[6.1.1].
    - phpunit/phpunit-mock-objects 6.1.1 requires php ^7.1 -> your PHP version (5.6.36) does not satisfy that requirement.
  Problem 17
    - Installation request for sebastian/comparator 2.1.3 -> satisfiable by sebastian/comparator[2.1.3].
    - sebastian/comparator 2.1.3 requires php ^7.0 -> your PHP version (5.6.36) does not satisfy that requirement.
  Problem 18
    - Installation request for sebastian/diff 3.0.0 -> satisfiable by sebastian/diff[3.0.0].
    - sebastian/diff 3.0.0 requires php ^7.1 -> your PHP version (5.6.36) does not satisfy that requirement.
  Problem 19
    - Installation request for sebastian/environment 3.1.0 -> satisfiable by sebastian/environment[3.1.0].
    - sebastian/environment 3.1.0 requires php ^7.0 -> your PHP version (5.6.36) does not satisfy that requirement.
  Problem 20
    - Installation request for sebastian/exporter 3.1.0 -> satisfiable by sebastian/exporter[3.1.0].
    - sebastian/exporter 3.1.0 requires php ^7.0 -> your PHP version (5.6.36) does not satisfy that requirement.
  Problem 21
    - Installation request for sebastian/global-state 2.0.0 -> satisfiable by sebastian/global-state[2.0.0].
    - sebastian/global-state 2.0.0 requires php ^7.0 -> your PHP version (5.6.36) does not satisfy that requirement.
  Problem 22
    - Installation request for sebastian/object-enumerator 3.0.3 -> satisfiable by sebastian/object-enumerator[3.0.3].
    - sebastian/object-enumerator 3.0.3 requires php ^7.0 -> your PHP version (5.6.36) does not satisfy that requirement.
  Problem 23
    - Installation request for sebastian/object-reflector 1.1.1 -> satisfiable by sebastian/object-reflector[1.1.1].
    - sebastian/object-reflector 1.1.1 requires php ^7.0 -> your PHP version (5.6.36) does not satisfy that requirement.
  Problem 24
    - Installation request for sebastian/recursion-context 3.0.0 -> satisfiable by sebastian/recursion-context[3.0.0].
    - sebastian/recursion-context 3.0.0 requires php ^7.0 -> your PHP version (5.6.36) does not satisfy that requirement.
  Problem 25
    - Installation request for symfony/browser-kit v4.0.8 -> satisfiable by symfony/browser-kit[v4.0.8].
    - symfony/browser-kit v4.0.8 requires php ^7.1.3 -> your PHP version (5.6.36) does not satisfy that requirement.
  Problem 26
    - Installation request for symfony/css-selector v4.0.8 -> satisfiable by symfony/css-selector[v4.0.8].
    - symfony/css-selector v4.0.8 requires php ^7.1.3 -> your PHP version (5.6.36) does not satisfy that requirement.
  Problem 27
    - Installation request for symfony/dom-crawler v4.0.8 -> satisfiable by symfony/dom-crawler[v4.0.8].
    - symfony/dom-crawler v4.0.8 requires php ^7.1.3 -> your PHP version (5.6.36) does not satisfy that requirement.
  Problem 28
    - Installation request for symfony/yaml v4.0.8 -> satisfiable by symfony/yaml[v4.0.8].
    - symfony/yaml v4.0.8 requires php ^7.1.3 -> your PHP version (5.6.36) does not satisfy that requirement.
  Problem 29
    - Installation request for theseer/tokenizer 1.1.0 -> satisfiable by theseer/tokenizer[1.1.0].
    - theseer/tokenizer 1.1.0 requires php ^7.0 -> your PHP version (5.6.36) does not satisfy that requirement.
  Problem 30
    - swiftmailer/swiftmailer v6.0.2 requires php >=7.0.0 -> your PHP version (5.6.36) does not satisfy that requirement.
    - yiisoft/yii2-swiftmailer 2.1.1 requires swiftmailer/swiftmailer ~6.0 -> satisfiable by swiftmailer/swiftmailer[v6.0.2].
    - Installation request for yiisoft/yii2-swiftmailer 2.1.1 -> satisfiable by yiisoft/yii2-swiftmailer[2.1.1].

After attempting in verbose mode to determine the source, I found it was coming from the lock file.

Reading ./composer.lock
Loading composer repositories with package information
Installing dependencies (including require-dev) from lock file
Reading ./composer.lock
Resolving dependencies through SAT
Dependency resolution completed in 0.001 seconds
Your requirements could not be resolved to an installable set of packages.

I renamed the lock file to test, and was able to then complete a composer install.

So there is something in the lock file that is still forcing the php version, just a heads up.

[akiraz2]

Big thanks!
I fix and release new version
If you have some other mistakes or bugs, please add new issues!