use a built REVISION file as a backup revision source

morituri/common/common.py

@@ -339,10 +339,29 @@ def getRevision():
     Get a revision tag for the current git source tree.
 
     Appends -modified in case there are local modifications.
+
+    If this is not a git tree, return the top-level REVISION contents instead.
+
+    Finally, return unknown.
     """
-    describe = commands.getoutput('git describe')
+    topsrcdir = os.path.join(os.path.dirname(__file__), '..', '..')
 
-    if commands.getoutput('git diff-index --name-only HEAD --'):
-        describe += '-modified'
+    # only use git if our src directory looks like a git checkout
+    # if you run git regardless, it recurses up until it finds a .git,
+    # which may be higher than your current source tree
+    if os.path.exists(os.path.join(topsrcdir, '.git')):
 
-    return describe
+        status, describe = commands.getstatusoutput('git describe')
+        if status == 0:
+            if commands.getoutput('git diff-index --name-only HEAD --'):
+                describe += '-modified'
+
+            return describe
+
+    # check for a top-level REIVISION file
+    path = os.path.join(topsrcdir, 'REVISION')
+    if os.path.exists(path):
+        revision = open(path).read().strip()
+        return revision
+
+    return '(unknown)'