[LNT] Python 3 support: Minor automatic 2to3 fixups

[hubert.reinterpretcast]

Summary

Automatic fixups done using 2to3:

• 2to3 -f numliterals
• 2to3 -f dict
• 2to3 -f map
• 2to3 -f exec

The exec call is additionally updated to have a string argument as noted by @thopre.
The changes cover the files found to be affected when running tests (without result submission).

[thopre]

I got a lot more changes with futurize. In particular it adds:

+from builtins import map
+from builtins import zip

everywhere where map or zip is used, to ensure python3 behavior with python2.

lnt/lnttool/create.py

162

I initially thought of using

os.chmod(wsgi_path, S_IRUSR|S_IWUSR|S_IXUSR|S_IRGRP|S_IWGRP|S_IROTH|S_IWOTH)

instead. Maybe 0o755 is indeed more readable.

lnt/server/instance.py

57

exec in Python3 does not read from a file descriptor according to the doc. You'd need exec(open(config_path).read(), config_data) AFAIK.

See [1] (which contains "If it is an open file, the file is parsed until EOF and executed") Vs [2] (which contains "object must be either a string or a code object").

[1] https://docs.python.org/2/reference/simple_stmts.html#grammar-token-exec-stmt
[2] https://docs.python.org/3/library/functions.html#exec

[hubert.reinterpretcast]

In D67534#1669092, @thopre wrote:

I got a lot more changes with futurize. In particular it adds:

+from builtins import map
+from builtins import zip

everywhere where map or zip is used, to ensure python3 behavior with python2.

I'm not sure it is worth requiring an additional package (future).

lnt/lnttool/create.py

162

I think 0o755 is more readable.

lnt/server/instance.py

57

Confirmed:

TypeError: exec() arg 1 must be a string, bytes or code object

Will change.

[thopre]

In D67534#1669275, @hubert.reinterpretcast wrote:

In D67534#1669092, @thopre wrote:

I got a lot more changes with futurize. In particular it adds:

+from builtins import map
+from builtins import zip

everywhere where map or zip is used, to ensure python3 behavior with python2.

I'm not sure it is worth requiring an additional package (future).

Ah apparently it's only to ensure the new code is not too slow on python2: https://python-future.org/compatible_idioms.html#map

So I agree, this can be skipped, especially given how soon will python2 be EOL.

[hubert.reinterpretcast]

• Update exec call to have a string argument

[cmatthews]

LGTM.

lnt/formats/__init__.py

 """
 Utilities for converting to LNT's test format.
 
 LNT formats are described by dictionaries with 'name', 'read', and 'write'
 fields. Only the 'name' field is required. The 'read' field should be a
 callable taking a path_or_file object, the 'write' function should be a
 callable taking a Python object to write, and the path_or_file to write to.
 """
 
 from PlistFormat import format as plist
 from JSONFormat import format as json
 
 formats = [plist, json]
 formats_by_name = dict((f['name'], f) for f in formats)
-format_names = formats_by_name.keys()
+format_names = list(formats_by_name.keys())
 
 
 def get_format(name):
     """get_format(name) -> [format]
 
     Loookup a format object by name.
     """
 

lnt/lnttool/create.py

LNT configuration.
     cfg_version = kConfigVersion
     cfg_file = open(cfg_path, 'w')
     cfg_file.write(kConfigTemplate % locals())
     cfg_file.close()
 
     wsgi_file = open(wsgi_path, 'w')
     wsgi_file.write(kWSGITemplate % locals())
     wsgi_file.close()
-    os.chmod(wsgi_path, 0755)
+    os.chmod(wsgi_path, 0o755)
 
     # Execute an upgrade on the database to initialize the schema.
     lnt.server.db.migrate.update_path(db_path)
 
     print 'created LNT configuration in %r' % basepath
     print '  configuration file: %s' % cfg_path
     print '  WSGI app          : %s' % wsgi_path
     print '  database file     : %s' % db_path

lnt/server/instance.py

def frompath(path):
                 config_path = os.path.join(tmpdir, filenames[0], "lnt.cfg")
         else:
             config_path = path
 
         if not config_path or not os.path.exists(config_path):
             raise Exception("Invalid config: %r" % config_path)
 
         config_data = {}
-        exec open(config_path) in config_data
+        exec(open(config_path).read(), config_data)
         config = lnt.server.config.Config.from_data(config_path, config_data)
 
         return Instance(config_path, config, tmpdir)
 
     def __init__(self, config_path, config, tmpdir=None):
         self.config_path = config_path
         self.config = config
         self.tmpdir = tmpdir

lnt/testing/__init__.py

class TestSamples:
 
     def __init__(self, name, data, info={}, conv_f=float):
         """Create an instance representing the samples converted into
         floating-point values using the conv_f function.
         """
         self.name = str(name)
         self.info = dict((str(key), str(value))
                          for key, value in info.items())
-        self.data = map(conv_f, data)
+        self.data = list(map(conv_f, data))
 
     def render(self):
         """Return info from this instance in a dictionary that respects
         the LNT report format when printed as json.
         """
         return {'Name': self.name,
                 'Info': self.info,
                 'Data': self.data}