Add base class for package exceptions.

AUTHORS

@@ -17,5 +17,6 @@ Contributors are:
 -Phil Elson <pelson _dot_ pub _at_ gmail.com>
 -Bernard `Guyzmo` Pratz <guyzmo+gitpython+pub@m0g.net>
 -Timothy B. Hartman <tbhartman _at_ gmail.com>
+-Konstantin Popov <konstantin.popov.89 _at_ yandex.ru>
 
 Portions derived from other open source works and are clearly marked.

git/exc.py

@@ -9,19 +9,23 @@
 from git.compat import UnicodeMixin, safe_decode, string_types
 
 
-class InvalidGitRepositoryError(Exception):
+class GitError(Exception):
+    """ Base class for all package exceptions """
+
+
+class InvalidGitRepositoryError(GitError):
     """ Thrown if the given repository appears to have an invalid format.  """
 
 
 class WorkTreeRepositoryUnsupported(InvalidGitRepositoryError):
     """ Thrown to indicate we can't handle work tree repositories """
 
 
-class NoSuchPathError(OSError):
+class NoSuchPathError(GitError, OSError):
     """ Thrown if a path could not be access by the system. """
 
 
-class CommandError(UnicodeMixin, Exception):
+class CommandError(UnicodeMixin, GitError):
     """Base class for exceptions thrown at every stage of `Popen()` execution.
 
     :param command:
@@ -74,7 +78,7 @@ def __init__(self, command, status, stderr=None, stdout=None):
         super(GitCommandError, self).__init__(command, status, stderr, stdout)
 
 
-class CheckoutError(Exception):
+class CheckoutError(GitError):
     """Thrown if a file could not be checked out from the index as it contained
     changes.
 
@@ -98,7 +102,7 @@ def __str__(self):
         return Exception.__str__(self) + ":%s" % self.failed_files
 
 
-class CacheError(Exception):
+class CacheError(GitError):
 
     """Base for all errors related to the git index, which is called cache internally"""
 
@@ -117,7 +121,7 @@ def __init__(self, command, status, stderr=None, stdout=None):
         self._msg = u"Hook('%s') failed%s"
 
 
-class RepositoryDirtyError(Exception):
+class RepositoryDirtyError(GitError):
     """Thrown whenever an operation on a repository fails as it has uncommitted changes that would be overwritten"""
 
     def __init__(self, repo, message):

git/test/test_exc.py

@@ -10,10 +10,17 @@
 
 import ddt
 from git.exc import (
+    InvalidGitRepositoryError,
+    WorkTreeRepositoryUnsupported,
+    NoSuchPathError,
     CommandError,
     GitCommandNotFound,
     GitCommandError,
+    CheckoutError,
+    CacheError,
+    UnmergedEntriesError,
     HookExecutionError,
+    RepositoryDirtyError,
 )
 from git.test.lib import TestBase
 
@@ -44,6 +51,26 @@
 @ddt.ddt
 class TExc(TestBase):
 
+    def test_ExceptionsHaveBaseClass(self):
+        from git.exc import GitError
+        self.assertIsInstance(GitError(), Exception)
+
+        exception_classes = [
+            InvalidGitRepositoryError,
+            WorkTreeRepositoryUnsupported,
+            NoSuchPathError,
+            CommandError,
+            GitCommandNotFound,
+            GitCommandError,
+            CheckoutError,
+            CacheError,
+            UnmergedEntriesError,
+            HookExecutionError,
+            RepositoryDirtyError,
+        ]
+        for ex_class in exception_classes:
+            self.assertTrue(issubclass(ex_class, GitError))
+
     @ddt.data(*list(itt.product(_cmd_argvs, _causes_n_substrings, _streams_n_substrings)))
     def test_CommandError_unicode(self, case):
         argv, (cause, subs), stream = case