hgfixes: added a fixer that makes bytes to be formatted correctly
This patch implement a fixer that replaces all calls to the '%' when bytes
arguments are used to a call to bytesformatter(), a function that knows how to
format byte strings. As one can't be sure if a formatting call is done when
only variables are used in a '%' call, these calls are also translated. The
bytesformatter, in runtime, makes sure to return the "raw" % operation if
that's what was intended.
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/contrib/hgfixes/fix_bytesmod.py Tue Aug 03 13:59:14 2010 -0300
@@ -0,0 +1,63 @@
+"""Fixer that changes bytes % whatever to a function that actually formats
+it."""
+
+from lib2to3 import fixer_base
+from lib2to3.fixer_util import is_tuple, Call, Comma, Name, touch_import
+
+# XXX: Implementing a blacklist in 2to3 turned out to be more troublesome than
+# blacklisting some modules inside the fixers. So, this is what I came with.
+
+blacklist = ['mercurial/demandimport.py',
+ 'mercurial/py3kcompat.py',
+ 'mercurial/i18n.py',
+ ]
+
+def isnumberremainder(formatstr, data):
+ try:
+ if data.value.isdigit():
+ return True
+ except AttributeError:
+ return False
+
+class FixBytesmod(fixer_base.BaseFix):
+ # XXX: There's one case (I suppose) I can't handle: when a remainder
+ # operation like foo % bar is performed, I can't really know what the
+ # contents of foo and bar are. I believe the best approach is to "correct"
+ # the to-be-converted code and let bytesformatter handle that case in
+ # runtime.
+ PATTERN = '''
+ term< formatstr=STRING '%' data=STRING > |
+ term< formatstr=STRING '%' data=atom > |
+ term< formatstr=NAME '%' data=any > |
+ term< formatstr=any '%' data=any >
+ '''
+
+ def transform(self, node, results):
+ if self.filename in blacklist:
+ return
+ elif self.filename == 'mercurial/util.py':
+ touch_import('.', 'py3kcompat', node=node)
+
+ formatstr = results['formatstr'].clone()
+ data = results['data'].clone()
+ formatstr.prefix = '' # remove spaces from start
+
+ if isnumberremainder(formatstr, data):
+ return
+
+ # We have two possibilities:
+ # 1- An identifier or name is passed, it is going to be a leaf, thus, we
+ # just need to copy its value as an argument to the formatter;
+ # 2- A tuple is explicitly passed. In this case, we're gonna explode it
+ # to pass to the formatter
+ # TODO: Check for normal strings. They don't need to be translated
+
+ if is_tuple(data):
+ args = [formatstr, Comma().clone()] + \
+ [c.clone() for c in data.children[:]]
+ else:
+ args = [formatstr, Comma().clone(), data]
+
+ call = Call(Name('bytesformatter', prefix = ' '), args)
+ return call
+