use a built REVISION file as a backup revision source

.gitignore

@@ -14,3 +14,4 @@ install-sh
 missing
 morituri.spec
 py-compile
+REVISION

Makefile.am

@@ -5,7 +5,7 @@ ACLOCAL_AMFLAGS = -I m4
 
 SUBDIRS = morituri bin etc doc m4 misc
 
-EXTRA_DIST = morituri.spec morituri.doap RELEASE README HACKING
+EXTRA_DIST = morituri.spec morituri.doap RELEASE README HACKING REVISION
 
 SOURCES = $(top_srcdir)/morituri/*.py $(top_srcdir)/morituri/*/*.py
 
@@ -38,6 +38,9 @@ PYCHECKER_BLACKLIST = \
 release: dist
 	make $(PACKAGE)-$(VERSION).tar.bz2.md5
 
+REVISION: $(top_srcdir)/.git
+	$(PYTHON) -c 'from morituri.configure import configure; print configure.revision' > REVISION
+
 # generate md5 sum files
 %.md5: %
 	md5sum $< > $@

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)'