patch: try harder to find the file to patch on file creation (issue2041)

accept the following patch header:
first line:  foo/a.orig
second line: foo/a

mercurial/patch.py

@@ -933,8 +933,10 b' def selectfile(afile_orig, bfile_orig, h'
     missing = not goodb and not gooda and not createfunc()
 
     # some diff programs apparently produce create patches where the
-    # afile is not /dev/null, but rather the same name as the bfile
-    if missing and afile == bfile:
+    # afile is not /dev/null, but afile starts with bfile
+    abasedir = afile[:afile.rfind('/') + 1]
+    bbasedir = bfile[:bfile.rfind('/') + 1]
+    if missing and abasedir == bbasedir and afile.startswith(bfile):
         # this isn't very pretty
         hunk.create = True
         if createfunc():

tests/test-import

@@ -351,10 +351,22 b' diff -Naur proj-orig/foo proj-new/foo'
 @@ -0,0 +1,1 @@
 +a
 EOF
+# some people have patches like the following too
+cat > create2.patch <<EOF
+diff -Naur proj-orig/foo proj-new/foo
+--- proj-orig/foo.orig  1969-12-31 16:00:00.000000000 -0800
++++ proj-new/foo        2009-07-17 16:50:45.801368000 -0700
+@@ -0,0 +1,1 @@
++a
+EOF
 hg init oddcreate
 cd oddcreate
 hg import --no-commit ../create.patch
 cat foo
+rm foo
+hg revert foo
+hg import --no-commit ../create2.patch
+cat foo
 
 echo % 'first line mistaken for email headers (issue 1859)'
 hg init emailconfusion

tests/test-import.out

@@ -305,6 +305,8 b' applying a.patch'
 % create file when source is not /dev/null
 applying ../create.patch
 a
+applying ../create2.patch
+a
 % first line mistaken for email headers (issue 1859)
 applying a.patch
 changeset:   0:5a681217c0ad