Support python in other than /usr/bin/python

[emaste]

Summary

Use /usr/local/bin/python if it exists and /usr/bin/python does not. If that also does not exist, try python from $PATH.

This allows check_lint.sh to work on FreeBSD without the need to manually specify PYTHON_EXECUTABLE.

[samsonov]

lib/sanitizer_common/scripts/check_lint.sh

15 ↗

(On Diff #26248)

You never set PYTHON_EXECUTABLE to /usr/bin/python, is it intentional, or you believe it would always be in PATH in this case?

16 ↗

(On Diff #26248)

I'd prefer to have this flattened:

if [ -z "${PYTHON_EXECUTABLE}" ] && [ -x /usr/bin/python ]; then
  PYTHON_EXECUTABLE = /usr/bin/python
fi
if [ -z "${PYTHON_EXECUTABLE}" ] && [ -x /usr/bin/local/python ]; then
  ....

then you may also factor this out to function.
Please make sure to not introduce bash-isms.

17 ↗

(On Diff #26248)

Maybe, we should just print the value ${PYTHON_EXECUTABLE} if it's non-empty below?

[MatzeB]

Why not use "/usr/bin/env python" to call the python that is in the users PATH?

[emaste]

I'm happy to just switch to /usr/bin/env python in the scripts if everyone's happy with that (leaving the explicit PYTHON_EXECUTABLE override as it was).

lib/sanitizer_common/scripts/check_lint.sh

15 ↗

(On Diff #26248)

If it's in /usr/bin/python the PTYHON_EXECUTABLE can remain empty and #!/usr/bin/python at the beginning of the python scripts will take effect.

[emaste]

That is to say, it seemed like this intentionally used /usr/bin/python if it exists, rather than relying on python in the user's path, and I tried to keep that behaviour. I'm happy with either of

• #!/usr/bin/env python
• A find_python shell function that sets PYTHON_EXECUTABLE to the first match from /usr/bin/python, /usr/local/bin/python, $(which python)

[samsonov]

Let's try /usr/bin/env python then.

[emaste]

Just use /usr/bin/env python instead

[samsonov]

LGTM

lib/sanitizer_common/scripts/cpplint.py

-#!/usr/bin/python
+#!/usr/bin/env python
 #
 # Copyright (c) 2009 Google Inc. All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #    * Redistributions of source code must retain the above copyright

lib/sanitizer_common/scripts/litlint.py

-#!/usr/bin/python
+#!/usr/bin/env python
 #
 # litlint
 #
 # Ensure RUN commands in lit tests are free of common errors.
 #
 # If any errors are detected, litlint returns a nonzero exit code.
 #