OSTree is a tool for managing bootable, immutable, versioned filesystem trees. While it takes over some of the roles of traditional "package managers" like dpkg and rpm, it is not a package system; nor is it a tool for managing full disk images. Instead, it sits between those levels, offering a blend of the advantages (and disadvantages) of both.

For more information, see:

https://live.gnome.org/Projects/OSTree

Submitting patches

You can:

1. Send mail to ostree-list@gnome.org, with the patch attached
2. Submit a pull request against https://github.com/GNOME/ostree
3. Attach them to https://bugzilla.gnome.org/

Please look at "git log" and match the commit log style.

Running the test suite

Currently, ostree uses https://wiki.gnome.org/GnomeGoals/InstalledTests To run just ostree's tests:

./configure ... --enable-installed-tests
gnome-desktop-testing-runner -p 0 ostree/

Also, there is a regular:

make check

That runs a different set of tests.

Coding style

Indentation is GNU. Files should start with the appropriate mode lines.

Use GCC __attribute__((cleanup)) wherever possible. If interacting with a third party library, try defining local cleanup macros.

Use GError and GCancellable where appropriate.

Prefer returning gboolean to signal success/failure, and have output values as parameters.

Prefer linear control flow inside functions (aside from standard loops). In other words, avoid "early exits" or use of goto besides goto out;.

This is an example of an "early exit":

static gboolean
myfunc (...)
{
    gboolean ret = FALSE;

    /* some code */

    /* some more code */

    if (condition)
      return FALSE;

    /* some more code */

    ret = TRUE;
  out:
    return ret;
}

If you must shortcut, use:

if (condition)
  {
    ret = TRUE;
    goto out;
  }

A consequence of this restriction is that you are encouraged to avoid deep nesting of loops or conditionals. Create internal static helper functions, particularly inside loops. For example, rather than:

while (condition)
  {
    /* some code */
    if (condition)
      {
         for (i = 0; i < somevalue; i++)
           {
              if (condition)
                {
                  /* deeply nested code */
                }

                /* more nested code */
           }
      }
  }

Instead do this:

static gboolean
helperfunc (..., GError **error)
{
  if (condition)
   {
     /* deeply nested code */
   }

  /* more nested code */

  return ret;
}

while (condition)
  {
    /* some code */
    if (!condition)
      continue;

    for (i = 0; i < somevalue; i++)
      {
        if (!helperfunc (..., i, error))
          goto out;
      }
  }