Mbed-cli breaks PIP environment by installing/updating packages without user's consent

mbed-cli install pip packages and by doing so might break current environment.

$ pip install -U jsonschema==2.4.0
$ pip list |grep jsonschema
jsonschema                    2.4.0
$ mbed compile --config
[mbed] Auto-installing missing Python modules...

...
$ pip list |grep jsonschema
jsonschema                    2.6.0

Installing Pip packages might have unwanted side effect and should not be done if user is not requesting that. Such feature should be removed from mbed-cli

This blocks Icetea testing on my Mac.

Example:

$ icetea --version
1.0.1

# Run any mbed command
$ mbed compile --config >/dev/null
$ icetea --version
Traceback (most recent call last):
  File "/usr/local/bin/icetea", line 11, in <module>
    sys.exit(icetea_main())
  File "/usr/local/lib/python2.7/site-packages/icetea_lib/main.py", line 22, in icetea_main
    returnCode = manager.run()
  File "/usr/local/lib/python2.7/site-packages/icetea_lib/IceteaManager.py", line 219, in run
    version = get_fw_version()
  File "/usr/local/lib/python2.7/site-packages/icetea_lib/tools/tools.py", line 51, in get_fw_version
    pkg = require(get_fw_name())[0]
  File "/usr/local/lib/python2.7/site-packages/pkg_resources/__init__.py", line 892, in require
    needed = self.resolve(parse_requirements(requirements))
  File "/usr/local/lib/python2.7/site-packages/pkg_resources/__init__.py", line 783, in resolve
    raise VersionConflict(dist, req).with_context(dependent_req)
pkg_resources.ContextualVersionConflict: (jsonschema 2.6.0 (/usr/local/lib/python2.7/site-packages), Requirement.parse('jsonschema<=2.4.0'), set(['jsonmerge']))

Conclusion

Running any Mbed command breaks Icetea

[SeppoTakalo]

I would prefer opposite to be the default.

If I don’t ask it to install packages, it should not. So default should be false and only if --install-requirements would have been given, it could do so.

This would allow me to work with virtual environments, where I can be certain that running mbed build does not ruin my installation.

And version collisions are for Icetea+Mbed OS teams to fix, should not be handled in this issue.

[theotherjimmy]

@SeppoTakalo Does the switch --no-requirements resolve this? or would you need something more?