[gnome-continuous-yocto/gnomeostree-3.28-rocko: 3384/8267] devtool: update-recipe: check output before treating it as a string

[Emmanuele Bassi <ebassi src gnome org>]

commit 0ffd92707b089ecdd8ec81430cebae85aca4be00
Author: Paul Eggleton <paul eggleton linux intel com>
Date:   Thu Nov 10 14:45:14 2016 +1300

    devtool: update-recipe: check output before treating it as a string
    
    As of the move to Python 3 and the fixes we applied at that time,
    bb.process.run() will return a byte array of length 0 rather than an
    empty string if the output is empty. That may be a bug that we should
    fix, but for now it's easiest to just check the result here before
    treating it as a string. This fixes running "devtool update-recipe" or
    "devtool finish" on a recipe which has no source tree, for example
    initramfs-framework.
    
    Fixes [YOCTO #10563].
    
    (From OE-Core rev: 66bf6978fc807ecc422fb6b6328f68bc3406cf15)
    
    Signed-off-by: Paul Eggleton <paul eggleton linux intel com>
    Signed-off-by: Ross Burton <ross burton intel com>
    Signed-off-by: Richard Purdie <richard purdie linuxfoundation org>

 scripts/lib/devtool/standard.py |    9 +++++----
 1 files changed, 5 insertions(+), 4 deletions(-)
---
diff --git a/scripts/lib/devtool/standard.py b/scripts/lib/devtool/standard.py
index 4523048..1511641 100644
--- a/scripts/lib/devtool/standard.py
+++ b/scripts/lib/devtool/standard.py
@@ -332,10 +332,11 @@ def _git_ls_tree(repodir, treeish='HEAD', recursive=False):
         cmd.append('-r')
     out, _ = bb.process.run(cmd, cwd=repodir)
     ret = {}
-    for line in out.split('\0'):
-        if line:
-            split = line.split(None, 4)
-            ret[split[3]] = split[0:3]
+    if out:
+        for line in out.split('\0'):
+            if line:
+                split = line.split(None, 4)
+                ret[split[3]] = split[0:3]
     return ret
 
 def _git_exclude_path(srctree, path):