Can Mercurial be made to preserve file permissions?

Question

I've seen a number of blog posts, and have experienced for myself, that Mercurial does not preserve the permissions on files pushed from one repo to another. Does anyone know of a Mercurial extension that would preserve the permissions? (I'm assuming it can't be done wit a hook, because what does a hook know about permissions at the originating repo?)

Requested elaboration:

• If the only change to a file is a change in permissions (e.g., chmod o+r filename), attempts to commit the file fail with a message saying that the file has not changed.

• If I commit a file with permissions 600 (rw-------), then clone the repo, the same file in the clone has permissions 664 (rw-rw-r--):

  : nr@yorkie 6522 ; hg clone one two
  updating working directory
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  : nr@yorkie 6523 ; ls -l one two
  one:
  total 4
  -rw------- 1 nr nr 8 Aug 18 21:50 foo
  
  
  two:
  total 4
  -rw-rw-r-- 1 nr nr 8 Aug 18 21:51 foo
  

This examples shows that hg clone does not preserve permissions, but hg push does not preserve them either.

In my application, one repo is on a publically accessible path, and it's of major importance that

• Multiple users have the right to change the repo

• Files in the public repo become readable only when explicitly made readable.

Answer 1

It is not good idea to store permissions in VCS. However, Mercurial supports "executable" flag (that is not the same as permissions, although in Unix executable flag is part of permissions).

Answer 2

OK, I hate to answer my own question, but it looks like it can be done using hooks and an auxiliary tool (and a little chewing gum and baling wire):

1. Get David Hardeman's Metastore, which saves and restores file metadata.

2. Alter the sources so it will ignore directory .hg as well as .git.

3. Use the following Mercurial hooks:

    precommit.meta = metastore -s
   
   
    changegroup.update = hg update
    update.meta   = /usr/unsup/nr/bin/metastore -a
   

You have to add the .metadata file to the repo.

This lashup will work most of the time, but if you change only permissions and want to propagate it, you'll have to run metastore -s in order to push those changes into the .metadata file where hg will see the change; otherwise the commit thinks nothing is new.

Answer 3

What about using this solution from the Mercurial FAQ:

If you're using Mercurial for config file management, you might want to track file properties (ownership and permissions) too. Mercurial only tracks the executable bit of each file.

Here is an example of how to save the properties along with the files (works on Linux if you've the acl package installed):

# cd /etc && getfacl -R . >/tmp/acl.$$ && mv /tmp/acl.$$ .acl
# hg commit

This is far from perfect, but you get the idea. For a more sophisticated solution, check out etckeeper.

Answer 4

This is way late, but for the specific case of the /etc directory, etckeeper looks interesting.