Add pylint to depot_tools.

third_party/pylint/checkers/imports.py

Index: third_party/pylint/checkers/imports.py
diff --git a/third_party/pylint/checkers/imports.py b/third_party/pylint/checkers/imports.py
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+++ b/third_party/pylint/checkers/imports.py
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+# Copyright (c) 2003-2010 LOGILAB S.A. (Paris, FRANCE).
+# http://www.logilab.fr/ -- mailto:contact@logilab.fr
+#
+# This program is free software; you can redistribute it and/or modify it under
+# the terms of the GNU General Public License as published by the Free Software
+# Foundation; either version 2 of the License, or (at your option) any later
+# version.
+#
+# This program is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+# FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License along with
+# this program; if not, write to the Free Software Foundation, Inc.,
+# 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+"""imports checkers for Python code"""
+
+from logilab.common.graph import get_cycles, DotBackend
+from logilab.common.modutils import is_standard_module
+from logilab.common.ureports import VerbatimText, Paragraph
+
+from logilab import astng
+from logilab.astng import are_exclusive
+
+from pylint.interfaces import IASTNGChecker
+from pylint.checkers import BaseChecker, EmptyReport
+
+
+def get_first_import(node, context, name, base, level):
+    """return the node where [base.]<name> is imported or None if not found
+    """
+    first = None
+    found = False
+    for first in context.values():
+        if isinstance(first, astng.Import):
+            if name in [iname[0] for iname in first.names]:
+                found = True
+                break
+        elif isinstance(first, astng.From):
+            if base == first.modname and level == first.level and \
+                   name in [iname[0] for iname in first.names]:
+                found = True
+                break
+    if found and first is not node and not are_exclusive(first, node):
+        return first
+
+# utilities to represents import dependencies as tree and dot graph ###########
+
+def filter_dependencies_info(dep_info, package_dir, mode='external'):
+    """filter external or internal dependencies from dep_info (return a
+    new dictionary containing the filtered modules only)
+    """
+    if mode == 'external':
+        filter_func = lambda x: not is_standard_module(x, (package_dir,))
+    else:
+        assert mode == 'internal'
+        filter_func = lambda x: is_standard_module(x, (package_dir,))
+    result = {}
+    for importee, importers in dep_info.items():
+        if filter_func(importee):
+            result[importee] = importers
+    return result
+
+def make_tree_defs(mod_files_list):
+    """get a list of 2-uple (module, list_of_files_which_import_this_module),
+    it will return a dictionary to represent this as a tree
+    """
+    tree_defs = {}
+    for mod, files in mod_files_list:
+        node = (tree_defs, ())
+        for prefix in mod.split('.'):
+            node = node[0].setdefault(prefix, [{}, []])
+        node[1] += files
+    return tree_defs
+
+def repr_tree_defs(data, indent_str=None):
+    """return a string which represents imports as a tree"""
+    lines = []
+    nodes = data.items()
+    for i, (mod, (sub, files)) in enumerate(sorted(nodes, key=lambda x: x[0])):
+        if not files:
+            files = ''
+        else:
+            files = '(%s)' % ','.join(files)
+        if indent_str is None:
+            lines.append('%s %s' % (mod, files))
+            sub_indent_str = '  '
+        else:
+            lines.append('%s\-%s %s' % (indent_str, mod, files))
+            if i == len(nodes)-1:
+                sub_indent_str = '%s  ' % indent_str
+            else:
+                sub_indent_str = '%s| ' % indent_str
+        if sub:
+            lines.append(repr_tree_defs(sub, sub_indent_str))
+    return '\n'.join(lines)
+
+
+def dependencies_graph(filename, dep_info):
+    """write dependencies as a dot (graphviz) file
+    """
+    done = {}
+    printer = DotBackend(filename[:-4], rankdir = "LR")
+    printer.emit('URL="." node[shape="box"]')
+    for modname, dependencies in dep_info.items():
+        done[modname] = 1
+        printer.emit_node(modname)
+        for modname in dependencies:
+            if modname not in done:
+                done[modname] = 1
+                printer.emit_node(modname)
+    for depmodname, dependencies in dep_info.items():
+        for modname in dependencies:
+            printer.emit_edge(modname, depmodname)
+    printer.generate(filename)
+
+
+def make_graph(filename, dep_info, sect, gtype):
+    """generate a dependencies graph and add some information about it in the
+    report's section
+    """
+    dependencies_graph(filename, dep_info)
+    sect.append(Paragraph('%simports graph has been written to %s'
+                          % (gtype, filename)))
+
+
+# the import checker itself ###################################################
+
+MSGS = {
+    'F0401': ('Unable to import %s',
+              'Used when pylint has been unable to import a module.'),
+    'R0401': ('Cyclic import (%s)',
+              'Used when a cyclic import between two or more modules is \
+              detected.'),
+
+    'W0401': ('Wildcard import %s',
+              'Used when `from module import *` is detected.'),
+    'W0402': ('Uses of a deprecated module %r',
+              'Used a module marked as deprecated is imported.'),
+    'W0403': ('Relative import %r, should be %r',
+              'Used when an import relative to the package directory is \
+              detected.'),
+    'W0404': ('Reimport %r (imported line %s)',
+              'Used when a module is reimported multiple times.'),
+    'W0406': ('Module import itself',
+              'Used when a module is importing itself.'),
+
+    'W0410': ('__future__ import is not the first non docstring statement',
+              'Python 2.5 and greater require __future__ import to be the \
+              first non docstring statement in the module.'),
+    }
+
+class ImportsChecker(BaseChecker):
+    """checks for
+    * external modules dependencies
+    * relative / wildcard imports
+    * cyclic imports
+    * uses of deprecated modules
+    """
+
+    __implements__ = IASTNGChecker
+
+    name = 'imports'
+    msgs = MSGS
+    priority = -2
+
+    options = (('deprecated-modules',
+                {'default' : ('regsub', 'string', 'TERMIOS',
+                              'Bastion', 'rexec'),
+                 'type' : 'csv',
+                 'metavar' : '<modules>',
+                 'help' : 'Deprecated modules which should not be used, \
+separated by a comma'}
+                ),
+               ('import-graph',
+                {'default' : '',
+                 'type' : 'string',
+                 'metavar' : '<file.dot>',
+                 'help' : 'Create a graph of every (i.e. internal and \
+external) dependencies in the given file (report RP0402 must not be disabled)'}
+                ),
+               ('ext-import-graph',
+                {'default' : '',
+                 'type' : 'string',
+                 'metavar' : '<file.dot>',
+                 'help' : 'Create a graph of external dependencies in the \
+given file (report RP0402 must not be disabled)'}
+                ),
+               ('int-import-graph',
+                {'default' : '',
+                 'type' : 'string',
+                 'metavar' : '<file.dot>',
+                 'help' : 'Create a graph of internal dependencies in the \
+given file (report RP0402 must not be disabled)'}
+                ),
+
+               )
+
+    def __init__(self, linter=None):
+        BaseChecker.__init__(self, linter)
+        self.stats = None
+        self.import_graph = None
+        self.__int_dep_info = self.__ext_dep_info = None
+        self.reports = (('RP0401', 'External dependencies',
+                         self.report_external_dependencies),
+                        ('RP0402', 'Modules dependencies graph',
+                         self.report_dependencies_graph),
+                        )
+
+    def open(self):
+        """called before visiting project (i.e set of modules)"""
+        self.linter.add_stats(dependencies={})
+        self.linter.add_stats(cycles=[])
+        self.stats = self.linter.stats
+        self.import_graph = {}
+
+    def close(self):
+        """called before visiting project (i.e set of modules)"""
+        # don't try to compute cycles if the associated message is disabled
+        if self.linter.is_message_enabled('R0401'):
+            for cycle in get_cycles(self.import_graph):
+                self.add_message('R0401', args=' -> '.join(cycle))
+
+    def visit_import(self, node):
+        """triggered when an import statement is seen"""
+        modnode = node.root()
+        for name, _ in node.names:
+            importedmodnode = self.get_imported_module(modnode, node, name)
+            if importedmodnode is None:
+                continue
+            self._check_relative_import(modnode, node, importedmodnode, name)
+            self._add_imported_module(node, importedmodnode.name)
+            self._check_deprecated_module(node, name)
+            self._check_reimport(node, name)
+
+
+    def visit_from(self, node):
+        """triggered when a from statement is seen"""
+        basename = node.modname
+        if basename == '__future__':
+            # check if this is the first non-docstring statement in the module
+            prev = node.previous_sibling()
+            if prev:
+                # consecutive future statements are possible
+                if not (isinstance(prev, astng.From)
+                       and prev.modname == '__future__'):
+                    self.add_message('W0410', node=node)
+            return
+        modnode = node.root()
+        importedmodnode = self.get_imported_module(modnode, node, basename)
+        if importedmodnode is None:
+            return
+        self._check_relative_import(modnode, node, importedmodnode, basename)
+        self._check_deprecated_module(node, basename)
+        for name, _ in node.names:
+            if name == '*':
+                self.add_message('W0401', args=basename, node=node)
+                continue
+            self._add_imported_module(node, '%s.%s' % (importedmodnode.name, name))
+            self._check_reimport(node, name, basename, node.level)
+
+    def get_imported_module(self, modnode, importnode, modname):
+        try:
+            return importnode.do_import_module(modname)
+        except astng.InferenceError, ex:
+            if str(ex) != modname:
+                args = '%r (%s)' % (modname, ex)
+            else:
+                args = repr(modname)
+            self.add_message("F0401", args=args, node=importnode)
+
+    def _check_relative_import(self, modnode, importnode, importedmodnode,
+                               importedasname):
+        """check relative import. node is either an Import or From node, modname
+        the imported module name.
+        """
+        if 'W0403' not in self.active_msgs:
+            return
+        if importedmodnode.file is None:
+            return False # built-in module
+        if modnode is importedmodnode:
+            return False # module importing itself
+        if modnode.absolute_import_activated() or getattr(importnode, 'level', None):
+            return False
+        if importedmodnode.name != importedasname:
+            # this must be a relative import...
+            self.add_message('W0403', args=(importedasname, importedmodnode.name),
+                             node=importnode)
+
+    def _add_imported_module(self, node, importedmodname):
+        """notify an imported module, used to analyze dependencies"""
+        context_name = node.root().name
+        if context_name == importedmodname:
+            # module importing itself !
+            self.add_message('W0406', node=node)
+        elif not is_standard_module(importedmodname):
+            # handle dependencies
+            importedmodnames = self.stats['dependencies'].setdefault(
+                importedmodname, set())
+            if not context_name in importedmodnames:
+                importedmodnames.add(context_name)
+            if is_standard_module( importedmodname, (self.package_dir(),) ):
+                # update import graph
+                mgraph = self.import_graph.setdefault(context_name, set())
+                if not importedmodname in mgraph:
+                    mgraph.add(importedmodname)
+
+    def _check_deprecated_module(self, node, mod_path):
+        """check if the module is deprecated"""
+        for mod_name in self.config.deprecated_modules:
+            if mod_path == mod_name or mod_path.startswith(mod_name + '.'):
+                self.add_message('W0402', node=node, args=mod_path)
+
+    def _check_reimport(self, node, name, basename=None, level=0):
+        """check if the import is necessary (i.e. not already done)"""
+        if 'W0404' not in self.active_msgs:
+            return
+        frame = node.frame()
+        root = node.root()
+        contexts = [(frame, level)]
+        if root is not frame:
+            contexts.append((root, 0))
+        for context, level in contexts:
+            first = get_first_import(node, context, name, basename, level)
+            if first is not None:
+                self.add_message('W0404', node=node,
+                                 args=(name, first.fromlineno))
+
+
+    def report_external_dependencies(self, sect, _, dummy):
+        """return a verbatim layout for displaying dependencies"""
+        dep_info = make_tree_defs(self._external_dependencies_info().items())
+        if not dep_info:
+            raise EmptyReport()
+        tree_str = repr_tree_defs(dep_info)
+        sect.append(VerbatimText(tree_str))
+
+    def report_dependencies_graph(self, sect, _, dummy):
+        """write dependencies as a dot (graphviz) file"""
+        dep_info = self.stats['dependencies']
+        if not dep_info or not (self.config.import_graph
+                                or self.config.ext_import_graph
+                                or self.config.int_import_graph):
+            raise EmptyReport()
+        filename = self.config.import_graph
+        if filename:
+            make_graph(filename, dep_info, sect, '')
+        filename = self.config.ext_import_graph
+        if filename:
+            make_graph(filename, self._external_dependencies_info(),
+                       sect, 'external ')
+        filename = self.config.int_import_graph
+        if filename:
+            make_graph(filename, self._internal_dependencies_info(),
+                       sect, 'internal ')
+
+    def _external_dependencies_info(self):
+        """return cached external dependencies information or build and
+        cache them
+        """
+        if self.__ext_dep_info is None:
+            self.__ext_dep_info = filter_dependencies_info(
+                self.stats['dependencies'], self.package_dir(), 'external')
+        return self.__ext_dep_info
+
+    def _internal_dependencies_info(self):
+        """return cached internal dependencies information or build and
+        cache them
+        """
+        if self.__int_dep_info is None:
+            self.__int_dep_info = filter_dependencies_info(
+                self.stats['dependencies'], self.package_dir(), 'internal')
+        return self.__int_dep_info
+
+
+def register(linter):
+    """required method to auto register this checker """
+    linter.register_checker(ImportsChecker(linter))