Calling rehash is required after installing new python version

[dangitall]

I'm running on OS X and am observing that calling rehash is required 100% of the time after a new version of Python is installed with pyenv. My impression is that shouldn't be needed. Is this expected behavior?

$ python -V
Python 2.7.13
$ pyenv install 3.6.0
Installing Python-3.6.0...
Installed Python-3.6.0 to /Users/dan/.pyenv/versions/3.6.0

$ pyenv global 3.6.0
$ python -V
Python 2.7.13
$ pyenv rehash
$ python -V
Python 3.6.0

I see a similar issue after uninstalling a version. This is run immediately after the above commands:

$ pyenv uninstall 3.6.0
pyenv: remove /Users/dan/.pyenv/versions/3.6.0? y
$ python -V
bash: /Users/dan/.pyenv/shims/python: No such file or directory
$ pyenv versions
pyenv: version `3.6.0' is not installed (set by /Users/dan/.pyenv/version)
  system
$ pyenv rehash
$ python -V
Python 2.7.13

[yyuu]

Both install/uninstall are implemented to call pyenv-rehash automatically.

https://github.com/yyuu/pyenv/blob/v1.0.6/plugins/python-build/bin/pyenv-install#L276
https://github.com/yyuu/pyenv/blob/v1.0.6/plugins/python-build/bin/pyenv-uninstall#L83

[dangitall]

Yeah, I see that but it didn't really help me in the case above. Maybe it would make sense to do it any time the environment changes?