tests: ignore "undefined name 'memoryview'" pyflakes error on earlier Python

Before this patch, "test-check-pyflakes.t" shows unexpected "undefined
name 'memoryview'" error for "mercurial/util.py" on Python 2.6.x or
earlier, because they don't define symbol 'memoryview'.

This patch introduces excluding patterns into "filterpyflakes.py" to
ignore "undefined name 'memoryview'" pyflakes error on Python 2.6.x or
earlier

tests/filterpyflakes.py

@@ -1,52 +1,59 b''
 #!/usr/bin/env python
 
 # Filter output by pyflakes to control which warnings we check
 
 import sys, re, os
 
 def makekey(typeandline):
     """
     for sorting lines by: msgtype, path/to/file, lineno, message
 
     typeandline is a sequence of a message type and the entire message line
     the message line format is path/to/file:line: message
 
     >>> makekey((3, 'example.py:36: any message'))
     (3, 'example.py', 36, ' any message')
     >>> makekey((7, 'path/to/file.py:68: dummy message'))
     (7, 'path/to/file.py', 68, ' dummy message')
     >>> makekey((2, 'fn:88: m')) > makekey((2, 'fn:9: m'))
     True
     """
 
     msgtype, line = typeandline
     fname, line, message = line.split(":", 2)
     # line as int for ordering 9 before 88
     return msgtype, fname, int(line), message
 
 
 lines = []
 for line in sys.stdin:
     # We whitelist tests (see more messages in pyflakes.messages)
     pats = [
-            r"imported but unused",
-            r"local variable '.*' is assigned to but never used",
-            r"unable to detect undefined names",
-            r"undefined name '.*'",
+            (r"imported but unused", None),
+            (r"local variable '.*' is assigned to but never used", None),
+            (r"unable to detect undefined names", None),
            ]
-    for msgtype, pat in enumerate(pats):
-        if re.search(pat, line):
+    if sys.version_info >= (2, 7):
+        pats.append((r"undefined name '.*'", None))
+    else:
+        pats.append((r"undefined name '.*'", r"undefined name 'memoryview'"))
+    for msgtype, (pat, excl) in enumerate(pats):
+        if re.search(pat, line) and (not excl or not re.search(excl, line)):
             break # pattern matches
     else:
         continue # no pattern matched, next line
     fn = line.split(':', 1)[0]
     f = open(os.path.join(os.path.dirname(os.path.dirname(__file__)), fn))
     data = f.read()
     f.close()
     if 'no-' 'check-code' in data:
         continue
     lines.append((msgtype, line))
 
 for msgtype, line in sorted(lines, key=makekey):
     sys.stdout.write(line)
 print
+
+# self test of "undefined name" detection for other than 'memoryview'
+if False:
+    print undefinedname

tests/test-check-pyflakes.t

@@ -1,21 +1,22 b''
 #if test-repo pyflakes
 
   $ cd "`dirname "$TESTDIR"`"
 
 run pyflakes on all tracked files ending in .py or without a file ending
 (skipping binary file random-seed)
 
   $ hg locate 'set:**.py or grep("^!#.*python")' 2>/dev/null \
   > | xargs pyflakes 2>/dev/null | "$TESTDIR/filterpyflakes.py"
   contrib/win32/hgwebdir_wsgi.py:*: 'win32traceutil' imported but unused (glob)
   setup.py:*: 'sha' imported but unused (glob)
   setup.py:*: 'zlib' imported but unused (glob)
   setup.py:*: 'bz2' imported but unused (glob)
   setup.py:*: 'py2exe' imported but unused (glob)
   tests/hghave.py:*: '_lsprof' imported but unused (glob)
   tests/hghave.py:*: 'publish_cmdline' imported but unused (glob)
   tests/hghave.py:*: 'pygments' imported but unused (glob)
   tests/hghave.py:*: 'ssl' imported but unused (glob)
   contrib/win32/hgwebdir_wsgi.py:93: 'from isapi.install import *' used; unable to detect undefined names (glob)
+  tests/filterpyflakes.py:59: undefined name 'undefinedname'
   
 #endif