chore: deprecate the pre-deploy trigger in favor of the pre-release-builder trigger

docs/appendices/0.34.0-migration-guide.md

@@ -17,3 +17,7 @@
     ```shell
     dokku scheduler-k3s:set --global ingress-class traefik
     ```
+
+## Deprecations
+
+The `pre-deploy` plugin trigger is deprecated as of `0.34.4`. It is currently invoked during the `post-release-builder` plugin trigger, where image mutation is heavily discouraged. Users should instead move any trigger usage to the `pre-release-builder` plugin trigger. The `pre-deploy` plugin trigger will be removed in a future release.

docs/development/plugin-triggers.md

@@ -1934,6 +1934,9 @@ fi
 
 ### `pre-deploy`
 
+> [!WARNING]
+> Deprecated, please use `pre-release-builder` instead
+
 - Description: Allows the running of code before the app's processes are scaled up and after the docker images are prepared.
 - Invoked by: `dokku deploy`
 - Arguments: `$APP $IMAGE_TAG`

plugins/registry/triggers.go

@@ -90,13 +90,16 @@ func TriggerPostDelete(appName string) error {
 func TriggerPostReleaseBuilder(appName string, image string) error {
 	parts := strings.Split(image, ":")
 	imageTag := parts[len(parts)-1]
-	_, err := common.CallPlugnTrigger(common.PlugnTriggerInput{
-		Trigger:     "pre-deploy",
-		Args:        []string{appName, imageTag},
-		StreamStdio: true,
-	})
-	if err != nil {
-		return err
+	if common.PlugnTriggerExists("pre-deploy") {
+		common.LogWarn("Deprecated: please upgrade plugin to use 'pre-release-builder' plugin trigger instead of pre-deploy")
+		_, err := common.CallPlugnTrigger(common.PlugnTriggerInput{
+			Trigger:     "pre-deploy",
+			Args:        []string{appName, imageTag},
+			StreamStdio: true,
+		})
+		if err != nil {
+			return err
+		}
 	}
 
 	imageID, _ := common.DockerInspect(image, "{{ .Id }}")