inotify: fix issue1375, add a test.

The biggest problem was the data structure, which did not allow changing
a file into a directory or vice versa. This problem is fixed by 47d29dcb7266.

The walk() method also had an issue in this case:
 - we know 'path' as a directory. inotify server sleeps.
 - 'path' is deleted
 - 'path' is recreated as a file
 - the server catches up here, and see the deletion. it instantiates a scan(),
   which in its turn calls for walk(repo, path).
 - walk() then assumes that 'path' is a directory and calls os.listdir on it,
   which raises an OSError(errno.ENOTDIR)

Catch the error, and yield the file instead of the directory contents.

hgext/inotify/server.py

@@ -89,7 +89,11 @@ def walk(repo, root):
             yield fullpath, dirs, files
 
         except OSError, err:
-            if err.errno not in walk_ignored_errors:
+            if err.errno == errno.ENOTDIR:
+                # fullpath was a directory, but has since been replaced
+                # by a file.
+                yield fullpath, dirs, files
+            elif err.errno not in walk_ignored_errors:
                 raise
 
     return walkit(root, root == '')

tests/test-inotify

@@ -35,4 +35,19 @@ cd dir
 hg status .
 cd ..
 
+#issue 1375
+#Testing that we can remove a folder and then add a file with the same name
+echo % issue 1375
+
+mkdir h
+echo h > h/h
+hg ci -Am t
+hg rm h
+
+echo h >h
+hg add h
+
+hg status
+hg ci -m0
+
 kill `cat hg.pid`

tests/test-inotify.out

@@ -32,3 +32,9 @@ M dir/x
 ? hg.pid
 M dir/x
 M x
+% issue 1375
+adding h/h
+adding hg.pid
+removing h/h
+A h
+R h/h