Merge pyflakes-permission-denied-2841

Author: exarkun
Reviewer: jonathanj
Fixes: #2841

Handle permission errors when trying to read source files.

Author: exarkun

pyflakes/scripts/pyflakes.py

@@ -47,12 +47,13 @@ def checkPath(filename):
 
     @return: the number of warnings printed
     """
-    if os.path.exists(filename):
+    try:
         return check(file(filename, 'U').read() + '\n', filename)
-    else:
-        print >> sys.stderr, '%s: no such file' % (filename,)
+    except IOError, msg:
+        print >> sys.stderr, "%s: %s" % (filename, msg.args[1])
         return 1
 
+
 def main():
     warnings = 0
     args = sys.argv[1:]

pyflakes/test/test_script.py

@@ -44,7 +44,7 @@ def test_checkPathNonExisting(self):
         """
         err = StringIO()
         count = withStderrTo(err, lambda: checkPath('extremo'))
-        self.assertEquals(err.getvalue(), 'extremo: no such file\n')
+        self.assertEquals(err.getvalue(), 'extremo: No such file or directory\n')
         self.assertEquals(count, 1)
 
 
@@ -113,7 +113,6 @@ def test_nonDefaultFollowsDefaultSyntaxError(self):
         should include the line number of the syntax error.  However these
         exceptions do not include an offset.
         """
-
         source = """\
 def foo(bar=baz, bax):
     pass
@@ -137,7 +136,6 @@ def test_nonKeywordAfterKeywordSyntaxError(self):
         include the line number of the syntax error.  However these exceptions
         do not include an offset.
         """
-
         source = """\
 foo(bar=baz, bax)
 """
@@ -152,3 +150,18 @@ def test_nonKeywordAfterKeywordSyntaxError(self):
 %s:1: non-keyword arg after keyword arg
 foo(bar=baz, bax)
 """ % (sourcePath.path,))
+
+
+    def test_permissionDenied(self):
+        """
+        If the a source file is not readable, this is reported on standard
+        error.
+        """
+        sourcePath = FilePath(self.mktemp())
+        sourcePath.setContent('')
+        sourcePath.chmod(0)
+        err = StringIO()
+        count = withStderrTo(err, lambda: checkPath(sourcePath.path))
+        self.assertEquals(count, 1)
+        self.assertEquals(
+            err.getvalue(), "%s: Permission denied\n" % (sourcePath.path,))