Ad deprecation warnings

src/wagtailmedia/deprecation.py

@@ -1,6 +1,6 @@
-class RemovedInWagtailMedia012Warning(PendingDeprecationWarning):
+class RemovedInWagtailMedia014Warning(PendingDeprecationWarning):
     pass
 
 
-class RemovedInWagtailMedia013Warning(DeprecationWarning):
+class RemovedInWagtailMedia015Warning(DeprecationWarning):
     pass

src/wagtailmedia/edit_handlers.py

@@ -1,11 +1,13 @@
 from __future__ import annotations
 
+import warnings
 from typing import TYPE_CHECKING
 
 from django.template.loader import render_to_string
 
 from wagtail.admin.compare import ForeignObjectComparison
 from wagtail.admin.panels import FieldPanel
+from .deprecation import RemovedInWagtailMedia015Warning
 
 from .models import MediaType
 from .utils import format_audio_html, format_video_html
@@ -24,6 +26,26 @@ def __init__(self, field_name, media_type=None, *args, **kwargs):
 
         self.media_type = media_type
 
+        if self.media_type is None:
+            warnings.warn(
+                (
+                    "The `MediaChooserPanel` field panel is deprecated. "
+                    "Please use the `FieldPanel()` instead."
+                ),
+                RemovedInWagtailMedia015Warning,
+                stacklevel=2,
+            )
+        else:
+            warnings.warn(
+                (
+                    "The `MediaChooserPanel` field panel is deprecated. Please use the "
+                    "specialised `AudioChooserPanel()` for audio only "
+                    "and `VideoChooserPanel()` for video only."
+                ),
+                RemovedInWagtailMedia015Warning,
+                stacklevel=2,
+            )
+
     def clone_kwargs(self):
         kwargs = super().clone_kwargs()
         kwargs.update(media_type=self.media_type)