django_evolution.diff

Support for diffing project signatures.

Changed in version 2.2: Moved django_evolution.placeholders.NullFieldInitialCallback into its own module.

Classes

Diff(original_project_sig, target_project_sig)

Generates diffs between project signatures.
class django_evolution.diff.Diff(original_project_sig, target_project_sig)

Bases: object

Generates diffs between project signatures.

The resulting diff is contained in two attributes:

self.changed = {
    app_label: {
        'changed': {
            model_name : {
                'added': [ list of added field names ]
                'deleted': [ list of deleted field names ]
                'changed': {
                    field: [ list of modified property names ]
                },
                'meta_changed': {
                    'constraints': new value
                    'db_table_comment': new value
                    'indexes': new value
                    'index_together': new value
                    'unique_together': new value
                }
            }
        'deleted': [ list of deleted model names ]
    }
}
self.deleted = {
    app_label: [ list of models in deleted app ]
}
__init__(original_project_sig, target_project_sig)

Initialize the object.

Parameters:
is_empty(ignore_apps=True)

Return whether the diff is empty.

This is used to determine if both signatures are effectively equal. If ignore_apps is set, this will ignore changes caused by deleted applications.

Parameters:

ignore_apps (bool, optional) – Whether to ignore changes to the applications list.

Returns:

True if the diff is empty and signatures are equal. False if there are changes between the signatures.

Return type:

bool

__str__()

Return a string description of the diff.

This will describe the changes found in the diff, for human consumption.

Returns:

The string representation of the diff.

Return type:

unicode

evolution()

Return the mutations needed for resolving the diff.

This will attempt to return a hinted evolution, consisting of a series of mutations for each affected application. These mutations will convert the database from the original to the target signatures.

Returns:

An ordered dictionary of mutations. Each key is an application label, and each value is a list of mutations for the application.

Return type:

collections.OrderedDict