Fixes #88: If merge.tool doesn't exist in ~/.gitconfig then inform user

Signed-off-by: Petr Hracek <phracek@redhat.com>

rebasehelper/application.py

@@ -288,6 +288,7 @@ def patch_sources(self, sources):
         # Patch sources
         self.kwargs['diff_tool'] = self.conf.difftool
         git_helper = GitHelper(sources[0])
+        git_helper.check_git_config()
         patch = Patcher(self.conf.patchtool)
 
         self.rebase_spec_file.update_changelog(self.rebase_spec_file.get_new_log(git_helper))
@@ -399,7 +400,6 @@ def print_summary(self):
     def run(self):
         sources = self.prepare_sources()
 
-        GitHelper.check_git_config()
         if not self.conf.build_only:
             self.patch_sources(sources)
 

rebasehelper/utils.py

@@ -512,25 +512,13 @@ def _call_git_command(self, command, input_file=None, output_file=None):
                 output_data.append(o.strip())
         return ret_code, output_data
 
-    @staticmethod
-    def check_git_config():
+    def check_git_config(self):
         """
         Function checks whether you have setup a merge tool in ~/.gitconfig
         :return: True or False
         """
-        git_config = []
+        merge = self.command_config('--get', 'merge.tool')
         git_config_name = os.path.expanduser('~/{0}'.format(settings.GIT_CONFIG))
-        try:
-            with open(git_config_name) as f:
-                git_config = f.readlines()
-        except IOError as ioer:
-            raise RebaseHelperError("Unable to open and read SPEC file '{0}'. {1}".format(git_config_name,
-                                                                                          exc_as_decode_string(ioer)))
-
-        if not git_config:
-            raise RebaseHelperError("File {0} is empty".format(git_config_name))
-
-        merge = [x.strip() for x in git_config if x.startswith('[merge]')]
         if not merge:
             message = """[merge] section is not defined in {0}.\n
 One of the possible configuration can be:\n
@@ -687,4 +675,6 @@ def command_config(self, parameters, variable=None):
         cmd.append(parameters)
         cmd.append(variable)
         ret_code, output = self._call_git_command(cmd)
+        if not output:
+            return None
         return output[0]