Merge fix for #8286 from 3.2

1 files changed, 134 insertions, 0 deletions

diff --git a/Lib/packaging/tests/fixer/fix_idioms.py b/Lib/packaging/tests/fixer/fix_idioms.py
new file mode 100644
index 0000000000..64f5ea0516
--- /dev/null
+++ b/Lib/packaging/tests/fixer/fix_idioms.py
@@ -0,0 +1,134 @@
+"""Adjust some old Python 2 idioms to their modern counterparts.
+
+* Change some type comparisons to isinstance() calls:
+    type(x) == T -> isinstance(x, T)
+    type(x) is T -> isinstance(x, T)
+    type(x) != T -> not isinstance(x, T)
+    type(x) is not T -> not isinstance(x, T)
+
+* Change "while 1:" into "while True:".
+
+* Change both
+
+    v = list(EXPR)
+    v.sort()
+    foo(v)
+
+and the more general
+
+    v = EXPR
+    v.sort()
+    foo(v)
+
+into
+
+    v = sorted(EXPR)
+    foo(v)
+"""
+# Author: Jacques Frechet, Collin Winter
+
+# Local imports
+from lib2to3 import fixer_base
+from lib2to3.fixer_util import Call, Comma, Name, Node, syms
+
+CMP = "(n='!=' | '==' | 'is' | n=comp_op< 'is' 'not' >)"
+TYPE = "power< 'type' trailer< '(' x=any ')' > >"
+
+class FixIdioms(fixer_base.BaseFix):
+
+    explicit = False # The user must ask for this fixer
+
+    PATTERN = r"""
+        isinstance=comparison< %s %s T=any >
+        |
+        isinstance=comparison< T=any %s %s >
+        |
+        while_stmt< 'while' while='1' ':' any+ >
+        |
+        sorted=any<
+            any*
+            simple_stmt<
+              expr_stmt< id1=any '='
+                         power< list='list' trailer< '(' (not arglist<any+>) any ')' > >
+              >
+              '\n'
+            >
+            sort=
+            simple_stmt<
+              power< id2=any
+                     trailer< '.' 'sort' > trailer< '(' ')' >
+              >
+              '\n'
+            >
+            next=any*
+        >
+        |
+        sorted=any<
+            any*
+            simple_stmt< expr_stmt< id1=any '=' expr=any > '\n' >
+            sort=
+            simple_stmt<
+              power< id2=any
+                     trailer< '.' 'sort' > trailer< '(' ')' >
+              >
+              '\n'
+            >
+            next=any*
+        >
+    """ % (TYPE, CMP, CMP, TYPE)
+
+    def match(self, node):
+        r = super(FixIdioms, self).match(node)
+        # If we've matched one of the sort/sorted subpatterns above, we
+        # want to reject matches where the initial assignment and the
+        # subsequent .sort() call involve different identifiers.
+        if r and "sorted" in r:
+            if r["id1"] == r["id2"]:
+                return r
+            return None
+        return r
+
+    def transform(self, node, results):
+        if "isinstance" in results:
+            return self.transform_isinstance(node, results)
+        elif "while" in results:
+            return self.transform_while(node, results)
+        elif "sorted" in results:
+            return self.transform_sort(node, results)
+        else:
+            raise RuntimeError("Invalid match")
+
+    def transform_isinstance(self, node, results):
+        x = results["x"].clone() # The thing inside of type()
+        T = results["T"].clone() # The type being compared against
+        x.prefix = ""
+        T.prefix = " "
+        test = Call(Name("isinstance"), [x, Comma(), T])
+        if "n" in results:
+            test.prefix = " "
+            test = Node(syms.not_test, [Name("not"), test])
+        test.prefix = node.prefix
+        return test
+
+    def transform_while(self, node, results):
+        one = results["while"]
+        one.replace(Name("True", prefix=one.prefix))
+
+    def transform_sort(self, node, results):
+        sort_stmt = results["sort"]
+        next_stmt = results["next"]
+        list_call = results.get("list")
+        simple_expr = results.get("expr")
+
+        if list_call:
+            list_call.replace(Name("sorted", prefix=list_call.prefix))
+        elif simple_expr:
+            new = simple_expr.clone()
+            new.prefix = ""
+            simple_expr.replace(Call(Name("sorted"), [new],
+                                     prefix=simple_expr.prefix))
+        else:
+            raise RuntimeError("should not have reached here")
+        sort_stmt.remove()
+        if next_stmt:
+            next_stmt[0].prefix = sort_stmt._prefix