[PATCH 05/14] [git] Use a new predicate to determine the need to stash

[Dirk Wallenstein <halsmit t-online de>]

Introduce a predicate to test if the repository is dirty, optionally
including existing submodules.
This function is used to recognize uncommited changes to be stashed.
This should now work more reliable in the face of changes in submodules,
as the output of 'git diff --submodule' may have multiple lines, where
not every line starts with 'Submodule '.
To reliably exclude differences in submodules, a dependency to a two
year old git version is added.

Signed-off-by: Dirk Wallenstein <halsmit t-online de>
---
 jhbuild/versioncontrol/git.py |   20 +++++++++++---------
 1 files changed, 11 insertions(+), 9 deletions(-)

diff --git a/jhbuild/versioncontrol/git.py b/jhbuild/versioncontrol/git.py
index f2826cd..23f752f 100644
--- a/jhbuild/versioncontrol/git.py
+++ b/jhbuild/versioncontrol/git.py
@@ -175,6 +175,16 @@ class GitBranch(Branch):
         return self._execute_git_predicate(
                 ['git', 'config', '--get', current_branch_remote_config])
 
+    def is_dirty(self, ignore_submodules=True):
+        submodule_options = []
+        if ignore_submodules:
+            if not self._check_version_git('1.5.6'):
+                raise CommandError(_('Need at least git-1.5.6 from June/08 '
+                        'to operate'))
+            submodule_options = ['--ignore-submodules']
+        return not self._execute_git_predicate(
+                ['git', 'diff', '--exit-code', '--quiet'] + submodule_options)
+
     def _check_version_git(self, version_spec):
         return check_version(['git', '--version'], r'git version ([\d.]+)',
                 version_spec, extra_env=get_git_extra_env())
@@ -295,16 +305,8 @@ class GitBranch(Branch):
         if update_mirror:
             self.update_dvcs_mirror(buildscript)
 
-        if self._check_version_git('1.7.0'):
-            git_diff_submodule = ['--submodule']
-        else:
-            git_diff_submodule = []
-
         stashed = False
-        git_diff_output = get_output(['git', 'diff'] + git_diff_submodule, **git_extra_args)
-        git_diff_output = '\n'.join([x for x in git_diff_output.splitlines() \
-                                     if not x.startswith('Submodule ')])
-        if git_diff_output:
+        if self.is_dirty(ignore_submodules=True):
             stashed = True
             buildscript.execute(['git', 'stash', 'save', 'jhbuild-stash'],
                     **git_extra_args)
-- 
1.7.1