User migration docs for 7.x -> 8.0

docs/source/changelog.md

@@ -2,7 +2,7 @@
 
 A summary of changes in ipywidgets. For more detailed information, see the issues and pull requests for the appropriate milestone on [GitHub](https://github.com/jupyter-widgets/ipywidgets).
 
-## [8.0](https://github.com/jupyter-widgets/ipywidgets/releases/tag/v8.0) (not released yet)
+## [8.0](https://github.com/jupyter-widgets/ipywidgets/releases/tag/v8.0)
 
 To see the full list of pull requests and issues, see the [8.0 milestone](https://github.com/jupyter-widgets/ipywidgets/milestone/30?closed=1) on GitHub.
 See also the 

docs/source/index.rst

@@ -86,6 +86,7 @@ some custom widget packages built on top of the Jupyter Widgets framework.
    :maxdepth: 1
 
    changelog.md
+   user_migration_guides.md
    migration_guides.md
 
 .. toctree::

docs/source/migration_guides.md

@@ -24,6 +24,9 @@ is released.
 We also recommend testing the migration in a completely new notebook, rather
 than one that contains widgets that you instantiated with ipywidgets 7.x.
 
+For a summarized list of relevant changes, please consult the "Developers" section of the
+[changelog](./changelog).
+
 ### Updating setup.py
 
 Start by updating the dependency in your `setup.py` or `setup.cfg` to support 8.x.

docs/source/user_migration_guides.md

@@ -0,0 +1,92 @@
+Migrating user code
+===================
+
+These are migration guides aimed specifically at user of ipywidgets.
+
+Migrating from 7.x to 8.0
+-------------------------
+
+For more details about the changes done for the 8.0 major version, please consult the
+[changelog](./changelog).
+
+### Code
+
+#### FileUpload
+
+The `data` and `metadata` traits have been removed, and the `value` trait revamped to
+be a list of dicts containing the file information. The keys of these dicts are:
+
+- `content`: The buffer of file data
+- `name`: The name of the file
+- `type`: The MIME type of the file content
+- `size`: The size of the buffer in bytes
+- `last_modified`: A UTC datetime representing the "last modified" value reported for the file
+
+Suggested migration: Rewrite all usage of `FileUpload` to use the new structure.
+If you need to support both 7.x and 8.x, you can e.g. write functions `get_file_buffer` and similar
+to wrap reads from the widget.
+
+#### Tooltips
+
+As part of an effort to make it possible to
+[set tooltips for all widgets](https://github.com/jupyter-widgets/ipywidgets/pull/2680),
+the old `description_tooltip` attribute for certain widgets was removed. Now all widgets
+that inherit `DOMWidget` have the attribute `tooltip` instead.
+
+Suggested migration: Search and replace `description_tooltip` to `tooltip`.
+TBD: ipywidgets should add a `description_tooltip` keyword argument to `DescriptionWidget`s, with
+a deprecation warning.
+
+#### Selection Widgets
+
+These widgets include: `ToggleButtons`, `Dropdown`, `RadioButtons`, `Select`, `SelectMultiple` `Selection`, `SelectionSlider`, and `SelectionRangeSlider`.
+
+For these, it is no longer possible to use `dict`s or other mapping types as values for the
+`options` trait. Using mapping types in this way has been deprecated since version 7.4, and
+will now raise a `TypeError`.
+
+Suggested migration: Clean up the `options` use. The following snippet can be used to convert
+a `dict` to the new format: `w.options = tuple((str(k), v) for k, v in your_dict.items())`.
+
+#### Description Sanitization
+
+The value of the `description` field of any widget that inherits `DescriptionWidget`
+(most widgets in ipywidgets) will now have its value sanitized for certain HTML content
+on the client side. If you are relying on HTML in this value, you might need to explicitly
+set the `description_allow_html` trait to `True`, depending on what kind of tags/attributes
+are used.
+
+Suggested migration: Only set `description_allow_html` if you are in full control of the
+value that is set.
+
+#### Layout.border
+
+While this change is strictly speaking backwards compatible, a word of caution is useful to
+those that want to use the new functionality:
+
+Four attributes have been added: `border_left`, `border_right`, `border_top` and `border_bottom`.
+These can be used to set the corresponding CSS border strings individually. Setting the
+`border` property overrides all of those four attributes to the new value of `border`. If
+the individual values are set to different values, *the `border` property will return `None`
+when you read its value*.
+
+#### Layout.overflow_x / overflow_y
+
+The previously deprecated traits `overflow_x` and `overflow_y`
+[have been removed](https://github.com/jupyter-widgets/ipywidgets/pull/2688). Please
+use the `overflow` trait instead.
+
+### Deployments
+
+#### Embedded CDN
+
+Please note that the default CDN of ipywidgets have changed from unpkg to jsDelivr. If
+you rely on the CDN being unpkg, this can be overridden by specifying the data
+attribute `data-jupyter-widgets-cdn` on the HTML manager script tag. See
+[embedding](./embedding) for details.
+
+#### widgetsnbextension
+
+The `widgetsnbextension` package is no longer a dependency of `ipywidgets`. Consequently,
+neither is the `notebook` package. If you need to keep `notebook` and widget support for it
+you will need to ensure they are explicitly stated in any environment bootstrapping.