Track whether webdiff was invoked from HEAD

Author: danvk

webdiff/app.py

@@ -219,6 +219,11 @@ def abs_path(path):
         return os.path.join(os.getcwd(), path)
 
 
+def is_webdiff_from_head():
+    '''Was webdiff invoked as `git webdiff` with no other non-flag args?'''
+    return os.environ.get('WEBDIFF_FROM_HEAD') != None
+
+
 def run():
     global A_DIR, B_DIR, DIFF, PORT
     try:

webdiff/gitwebdiff.py

@@ -1,10 +1,23 @@
 #!/usr/bin/env python
 '''This lets you run "git webdiff" instead of "git difftool".'''
 
+import os
 import subprocess
 import sys
 
+
+def any_nonflag_args(args):
+    """Do any args not start with '-'? If so, this isn't a HEAD diff."""
+    return len([x for x in args if not x.startswith('-')]) > 0
+
+
 def run():
+    if not any_nonflag_args(sys.argv[1:]):
+        # This tells webdiff that it was invoked as a simple "git webdiff", not
+        # "git webdiff <sha>". This allows special treatment (e.g. for
+        # staging diffhunks).
+        os.environ['WEBDIFF_FROM_HEAD'] = 'yes'
+    
     sys.exit(subprocess.call(
         'git difftool -d -x webdiff'.split(' ') + sys.argv[1:]))