Moving PTL to Python 3
- Ravi Vasista (Deactivated)
Links that might be useful
- https://docs.python.org/3.0/whatsnew/3.0.html - Changes from Python 2 to Python 3
- https://docs.python.org/2/library/2to3.html - Doc for Py2to3
It is interesting to note that the tool Py2to3, always returns the same object that the function used in Python 2 did, even when it is unnecessary. A few examples of this are given below -
- dict(map(map_fun, cols, row))
+ dict(list(map(map_fun, cols, row)))Python 2 returns a list when map is used and Python 3 returns a map object. The map object can be directly cast to a dictionary if needed.
- data.iteritems():
+ data.items():Python 2 returns a generator for dict.iteritems() so the tool converts this in Python 3 to dict.items()
- data.items():
+ list(data.items()):In this case however, dict.items() returns a list in Python 2 which is why the tool converted the generator returned by dict.items() explicitly to a list.
- data.keys()
+ list(data.keys())Similar to the previous case. Explicit conversion to a list in case of dict.keys()
- base64bytes = base64.b64encode("**Random String**".encode('utf-8'))
base64bytes.decode('utf-8')
This change is manual. Py2to3 does not take this into account. The b64encode function requires a byte-like object and returns one as well in Python 3, this was not the case for Python 2.
- urllib2.Request(url, json.dumps(data))
+ urllib.request.Request(url, json.dumps(data))urllib2 has changed to urllib and it's functions have been moved to sub packages.
- httplib.HTTPConnection(self.host, timeout=25)
+ http.client.HTTPConnection(self.host, timeout=25)- httplib has changed to http and it's functions have been moved to sub packages.
- filter(lambda x: x[0] == '**match**', filters):
+ [x for x in filters if x[0] == '**match**']:Filter like map now returns a filter object.
- Exceptions in Python 3 no longer have a message attribute. This has been replaced with str(e). This change is also manual.
Specifically from a PTL stand point -
- The defusedxml pypi page says it's for Python 2.7 but it is available through pip.
- The binaries have to have the .py extension, otherwise they will not be considered while running the tool for the workspace.
- There are issues while converting pbs_as and the conversion fails. This has to be done manually.
RefactoringTool: Skipping optional fixer: buffer
RefactoringTool: Skipping optional fixer: idioms
RefactoringTool: Skipping optional fixer: set_literal
RefactoringTool: Skipping optional fixer: ws_comma
RefactoringTool: Can't parse pbs_dev/pbspro/test/fw/bin/pbs_as: ParseError: bad input: type=1, value='elif', context=('\n ', (341, 4))
RefactoringTool: No files need to be modified.
RefactoringTool: There was 1 error:
RefactoringTool: Can't parse pbs_dev/pbspro/test/fw/bin/pbs_as: ParseError: bad input: type=1, value='elif', context=('\n ', (341, 4))
Link to Forum - http://community.pbspro.org/t/moving-to-python-3/1421
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