# HG changeset patch
# User Martin von Zweigbergk <martinvonz@google.com>
# Date 1421995355 28800
# Node ID 1ea90d140ee37e3bd4be8960c30e0654126b64a4
# Parent  7f23e67e9c38dcbd5a202a0c775ec58d5c15fa3b
trydiff: make filenames None when they don't exist

f1 and f2 are currently set always set to some filename, even for
added or deleted files. Let's instead set them to None to indicate
that one side of the diff doesn't exist. This lets us use the filename
variables instead of the content variables and simplify a bit since
the empty string is not a valid filename. More importantly, it paves
the way for further simplifications.

diff -r 7f23e67e9c38 -r 1ea90d140ee3 mercurial/patch.py
--- a/mercurial/patch.py	Tue Feb 10 10:57:58 2015 -0500
+++ b/mercurial/patch.py	Thu Jan 22 22:42:35 2015 -0800
@@ -1785,6 +1785,7 @@
         f1, f2 = f, f
         if opts.git or losedatafn:
             if f in addedset:
+                f1 = None
                 flag2 = ctx2.flags(f)
                 if f in copy:
                     if opts.git:
@@ -1797,6 +1798,7 @@
                             copyop = 'copy'
                         content1 = getfilectx(f1, ctx1).data()
             elif f in removedset:
+                f2 = None
                 if opts.git:
                     # have we already reported a copy above?
                     if (f in copyto and copyto[f] in addedset
@@ -1815,25 +1817,24 @@
                 # copy/rename
                 f in copy or
                 # empty file creation
-                (content1 is None and not content2) or
+                (not f1 and not content2) or
                 # empty file deletion
-                (not content1 and content2 is None) or
+                (not content1 and not f2) or
                 # create with flags
-                (content1 is None and flag2) or
+                (not f1 and flag2) or
                 # change flags
-                (content1 is not None and content2 is not None and
-                 flag1 != flag2)):
+                (f1 and f2 and flag1 != flag2)):
                 losedatafn(f)
 
-        path1 = posixpath.join(prefix, f1)
-        path2 = posixpath.join(prefix, f2)
+        path1 = posixpath.join(prefix, f1 or f2)
+        path2 = posixpath.join(prefix, f2 or f1)
         header = []
         if opts.git:
             header.append('diff --git %s%s %s%s' %
                           (aprefix, path1, bprefix, path2))
-            if content1 is None: # added
+            if not f1: # added
                 header.append('new file mode %s' % gitmode[flag2])
-            elif content2 is None: # removed
+            elif not f2: # removed
                 header.append('deleted file mode %s' % gitmode[flag1])
             else:  # modified/copied/renamed
                 mode1, mode2 = gitmode[flag1], gitmode[flag2]