Ergonomic, hermetic, user-friendly software build system for Python, Go, Java, Kotlin, Protobuf, Scala, Shell. Pants lets you fearlessly scale up your codebase!

Pants

OK, what does this say for you?:
```
$ ./pants options --scope=python-setup --name=interpreter-constraints
python-setup.interpreter_constraints = ['CPython&gt;=2.7,&lt;3'] (from CONFIG in pants.ini)
```

Also - can you paste the full output of your command run as so?:
```
./pants -ldebug --print-exception-stacktrace ...
```

python-setup.interpreter_constraints = [‘CPython&gt;=2.7,&lt;3’] (from HARDCODED)

Do you have a CPython 2.7 binary on your PATH? - you must for `./pants` to have bootstrapped at all. Also, if you can provide the full debug output I suggested above, that would be helpful.