PyAPI: temporary context override support

Support a way to temporarily override the context from Python.

- Added method `Context.temp_override` context manager.
- Special support for windowing variables "window", "area" and "region",
  other context members such as "active_object".
- Nesting context overrides is supported.
- Previous windowing members are restored when the context exists unless
  they have been removed.
- Overriding context members by passing a dictionary into operators in
  `bpy.ops` has been deprecated and warns when used.

This allows the window in a newly loaded file to be used, see: T92464

Reviewed by: mont29

Ref D13126

1 files changed, 19 insertions, 0 deletions

diff --git a/doc/python_api/examples/bpy.types.Context.temp_override.1.py b/doc/python_api/examples/bpy.types.Context.temp_override.1.py
new file mode 100644
index 00000000000..68f0eef93c3
--- /dev/null
+++ b/doc/python_api/examples/bpy.types.Context.temp_override.1.py
@@ -0,0 +1,19 @@
+"""
+Overriding the context can be used to temporarily activate another ``window`` / ``area`` & ``region``,
+as well as other members such as the ``active_object`` or ``bone``.
+
+Notes:
+
+- When overriding window, area and regions: the arguments must be consistent,
+  so any region argument that's passed in must be contained by the current area or the area passed in.
+  The same goes for the area needing to be contained in the current window.
+
+- Temporary context overrides may be nested, when this is done, members will be added to the existing overrides.
+
+- Context members are restored outside the scope of the context.
+  The only exception to this is when the data is no longer available.
+
+  In the event windowing data was removed (for example), the state of the context is left as-is.
+  While this isn't likely to happen, explicit window operation such as closing windows or loading a new file
+  remove the windowing data that was set before the temporary context was created.
+"""