[Kimchi-devel] [PATCH][Gingerbase] Do not use default value when declare a function

[Rodrigo Trujillo]

-1
Please, send to Ginger/Gingerbase list

Rodrigo

On 06/07/2016 01:30 AM, Ramon Medeiros wrote:
> For mutable object as a default parameter in function and
> method-declarations the problem is, that the evaluation and creation
> takes place at exactly the same moment. The python-parser reads the
> function-head and evaluates it at the same moment.
>
> Most beginers assume that a new object is created at every call, but
> that's not correct. One object (in your example a list) is created at
> the moment of declaration and not on demand when you are calling the
> method.
>
> For imutable objects that's not a problem, because even if all calls
> share the same object, it's imutable and therefore it's properties
> remain the same.
>
> As a convention, must be used the None object for defaults to indicate
> the use of a default initialization, which now can take place in the
> function-body, which naturally is evaluated at call-time.
>
> Signed-off-by: Ramon Medeiros <ramonn at linux.vnet.ibm.com>
> ---
>   disks.py                | 4 +++-
>   model/packagesupdate.py | 4 +++-
>   2 files changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/disks.py b/disks.py
> index 2883431..a1ba7c2 100644
> --- a/disks.py
> +++ b/disks.py
> @@ -47,7 +47,9 @@ def _get_dev_node_path(maj_min):
>       return "/dev/%s" % data["DEVNAME"]
>
>
> -def _get_lsblk_devs(keys, devs=[]):
> +def _get_lsblk_devs(keys, devs=None):
> +    if devs is None:
> +        devs = []
>       out, err, returncode = run_command(
>           ["lsblk", "-Pbo"] + [','.join(keys)] + devs
>       )
> diff --git a/model/packagesupdate.py b/model/packagesupdate.py
> index 073667c..42011f7 100644
> --- a/model/packagesupdate.py
> +++ b/model/packagesupdate.py
> @@ -56,11 +56,13 @@ class PackageUpdateModel(object):
>
>           return self.host_swupdate.getUpdate(name)
>
> -    def _resolve_dependencies(self, package=None, dep_list=[]):
> +    def _resolve_dependencies(self, package=None, dep_list=None):
>           """
>           Resolve the dependencies for a given package from the dictionary of
>           eligible packages to be upgraded.
>           """
> +        if dep_list is None:
> +            dep_list = []
>           if package is None:
>               return []
>           dep_list.append(package)