improved flymake code and doc provided by Derek Harland

1 files changed, 90 insertions, 19 deletions

diff --git a/epylint.py b/epylint.py
index cfbf47b..01d6b81 100755
--- a/epylint.py
+++ b/epylint.py
@@ -1,25 +1,96 @@
-"""simple pylint wrapper for emacs intraction"""
+#!/usr/bin/env python
+# -*- coding: utf-8; mode: python; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- vim:fenc=utf-8:ft=python:et:sw=4:ts=4:sts=4
 
-import re
-import sys
+"""Emacs and Flymake compatible Pylint.
 
-from popen2 import popen3
+This script is for integration with emacs and is compatible with flymake mode.
+
+This version of epylint traverses out of packages before invoking pylint.  This avoids the reporting
+of errors that occur when a module within package uses a full package import path to get hold of
+another module within this package.
+
+For example:
+    - Suppose a package is structured as
+
+        a/__init__.py
+        a/b/x.py
+        a/c/y.py
+
+   - Then if y.py imports x as "from a.b import x" the following produces pylint errors
+
+       cd a/c; pylint y.py
+
+   - THe following obviously doesn't
+
+       pylint a/c/y.py
+
+   - As this script will be invoked by emacs within the directory of the file we are checking
+     we need to traverse down out of it to avoid these false positives.
+
+"""
+
+import sys, os, re
+from subprocess import Popen, PIPE
+
+
+def lint(filename):
+    """Pylint the given file.
+
+    When run from emacs we will be in the directory of a file, and passed its filename.
+    If this file is part of a package and is trying to import other modules from within
+    its own package or another package rooted in a directory below it, pylint will classify
+    it as a failed import.
+
+    To get around this, we traverse down the directory tree to find the root of the package this
+    module is in.  We then invoke pylint from this directory.
+
+    Finally, we must correct the filenames in the output generated by pylint so Emacs doesn't
+    become confused (it will expect just the original filename, while pylint may extend it with
+    extra directories if we've traversed down the tree)
+    """
+    # traverse downwards until we are out of a python package
+    fullPath = os.path.abspath(filename)
+    parentPath, childPath = os.path.dirname(fullPath), os.path.basename(fullPath)
+
+    while parentPath != "/" and os.path.exists(os.path.join(parentPath, '__init__.py')):
+        childPath = os.path.join(os.path.basename(parentPath), childPath)
+        parentPath = os.path.dirname(parentPath)
+
+    # Start pylint
+    process = Popen("pylint -f parseable -r n --disable-msg-cat=CRI '%s'" %
+                    childPath, shell=True, stdout=PIPE, stderr=PIPE,
+                    cwd=parentPath)
+    p = process.stdout
+
+    # The parseable line format is '%(path)s:%(line)s: [%(sigle)s%(obj)s] %(msg)s'
+    # NOTE: This would be cleaner if we added an Emacs reporter to pylint.reporters.text ..
+    regex = re.compile(r"\[(?P<type>[WE])(?P<remainder>.*?)\]")
+
+    def _replacement(mObj):
+        "Alter to include 'Error' or 'Warning'"
+        if mObj.group("type") == "W":
+            replacement = "Warning"
+        else:
+            replacement = "Error"
+        # replace as "Warning (W0511, funcName): Warning Text"
+        return "%s (%s%s):" % (replacement, mObj.group("type"), mObj.group("remainder"))
 
-def Run():
-    p, _in, _err = popen3("pylint -f parseable -r n --disable-msg-cat=CRI %s"
-                          % sys.argv[1])
     for line in p:
-        match = re.search("\\[([WE])(, (.+?))?\\]", line)
-        if match:
-            if match.group(1) == "W":
-                msg = "Warning"
-            else:
-                msg = "Error"
-            func = match.group(3)
-            if func:
-                line = re.sub("\\[([WE])(, (.+?))?\\]",
-                              "%s (%s):" % (msg, func), line)
-            else:
-                line = re.sub("\\[([WE])?\\]", "%s:" % msg, line)
+        # remove pylintrc warning
+        if line.startswith("No config file found"):
+            continue
+        line = regex.sub(_replacement, line, 1)
+        # modify the file name thats output to reverse the path traversal we made
+        parts = line.split(":")
+        if parts and parts[0] == childPath:
+            line = ":".join([filename] + parts[1:])
         print line,
+
     p.close()
+
+def Run():
+    lint(sys.argv[1])
+
+if __name__ == '__main__':
+    lint(sys.argv[1])
+