[gnome-continuous-yocto/gnomeostree-3.28-rocko: 7182/8267] externalsrc: Handle .git not being a directory

[Emmanuele Bassi <ebassi src gnome org>]

commit 3ca6085729d9a1025156c7a47f433981c2076995
Author: Joshua Watt <jpewhacker gmail com>
Date:   Wed Aug 9 21:18:32 2017 -0500

    externalsrc: Handle .git not being a directory
    
    Use git rev-parse to determine the location of the .git directory, in
    case it is not an immediate child of EXTERNALSRC (e.g. when using
    submodules). In the event git can't resolve the .git directory, fall
    back to the non-git method for hashing.
    
    (From OE-Core rev: 95e1341b49f7184d280a03f64f131a4468a06867)
    
    Signed-off-by: Joshua Watt <JPEWhacker gmail com>
    Signed-off-by: Richard Purdie <richard purdie linuxfoundation org>

 meta/classes/externalsrc.bbclass |   14 +++++++++++---
 1 files changed, 11 insertions(+), 3 deletions(-)
---
diff --git a/meta/classes/externalsrc.bbclass b/meta/classes/externalsrc.bbclass
index 9aabb42..8141f25 100644
--- a/meta/classes/externalsrc.bbclass
+++ b/meta/classes/externalsrc.bbclass
@@ -184,11 +184,19 @@ def srctree_hash_files(d, srcdir=None):
     import tempfile
 
     s_dir = srcdir or d.getVar('EXTERNALSRC')
-    git_dir = os.path.join(s_dir, '.git')
-    oe_hash_file = os.path.join(git_dir, 'oe-devtool-tree-sha1')
+    git_dir = None
+
+    try:
+        # git rev-parse returns the path relative to the current working
+        # directory
+        git_dir = os.path.join(s_dir,
+            subprocess.check_output(['git', 'rev-parse', '--git-dir'], cwd=s_dir).decode("utf-8").rstrip())
+    except subprocess.CalledProcessError:
+        pass
 
     ret = " "
-    if os.path.exists(git_dir):
+    if git_dir is not None:
+        oe_hash_file = os.path.join(git_dir, 'oe-devtool-tree-sha1')
         with tempfile.NamedTemporaryFile(prefix='oe-devtool-index') as tmp_index:
             # Clone index
             shutil.copyfile(os.path.join(git_dir, 'index'), tmp_index.name)