Git commit hash not found on linux

[lewis]

Running SasView on linux gives the error:

WARNING:root:Error while determining build number
  Command '['git', 'rev-parse', 'HEAD']' returned non-zero exit status 1

Then when SasView opens, clicking Help→About shows "Build: GIT_COMMIT" instead of the actual commit hash.

I believe this is because on linux, commands executed via subprocess.check_output() aren't ran from the cwd.

Adding something like:

command = 'git rev-parse HEAD'
if sys.platform.count('linux') > 0:
    command = 'cd ' + os.getcwd() + '; ' + command
git_revision = subprocess.check_output(command,
                stderr=FNULL,
                shell=True)

to sasview/__init__.py seems to do the job, but seems a bit hacky?

[butler]

The git hash is made to ensure that the commit hash for the build being distributed gets placed in the correct variable but should not prevent from running on a system without git. For Linux of course one is building in place I suspect? or is it from the ubuntu egg?

Either way — the point is that the first error is now generated on windows machines as well even when running the windows distributable built on DMSC machines. However it is mostly invisible as it only shows up in the log file (not even in the console). The About box has the last hash put there which is the one put there when built on DMSC machines and so correct.

HOWEVER — loading SasView now seems really slow compared to what it used to be. Suspect these are related?

[lewis]

I was building in place (running "python run.py" from the sasview repo)

SasView still runs fine, the error message just appears in the terminal

[wojciech]

The problem also appears on osx and when running from run.py the side effect is that it doesn't log to sasview.log.

The potential fix to the problem may involve pass in expect statement of sasview/init.py instead of:
import logging
import sys
logging.warning("Error while determining build number\n %s" % sys.exc_value)

[ajj]

Problem was that the call to subprocess was incorrectly assembled.

Fixed in a3f1c11

[krzywon]

Windows is now throwing this error:

WARNING:root:Error while determining build number
  Using command:
 ['git describe --tags'] 
 Output:

[krzywon]

Changing line 8 of sasview.init fixes the issue on Windows. Subprocess wants each argument as a separate list item. Could someone check this on linux?

git_revision = subprocess.check_output(['git', 'describe', '--tags'],

[ajj]

That will now break on linux and mac - on those platforms putting the arguments as a list made it fail.

[ajj]

In commit 654e8e0 line 8 now reads:

git_revision = subprocess.check_output(['git describe', '--tags'],

which works on mac and linux AFAICS. Will close ticket once confirmed that this works on windows.

(Has a single line of code ever been so commented on? )

[krzywon]

That didn't work so I changed it to be platform dependent. Confirm on Linux and Mac, please.

if platform.system() == "Windows":
    args = ['git', 'describe', '--tags']
else:
    args = ['git describe --tags']
git_revision = subprocess.check_output(args,

[ajj]

Fixed by jkrzywon as above.

For future reference: ​https://docs.python.org/2/library/subprocess.html#popen-constructor contains at least the statement that how the arguments to subprocess are marshalled and executed depends on the OS. Next time I'll RTFM properly.