Deprecate ineffective images_panel

The images_panel key in HORIZON_CONFIG setting dict was once added
during Newton cycle but was removed when ANGULAR_FEATURES option was
added in the same cycle[1].

Because the parameter has have no effect for long, this deprecates
the parameter so that we can remove it in a future release instead of
fixing it.

[1] https://review.opendev.org/c/openstack/horizon/+/353377

Change-Id: I376af3b7c4525036bf1bb449cb71490495395f2c

manifests/init.pp

@@ -406,11 +406,6 @@
 #    Valid values are 'on' and 'off'
 #    Defaults to 'off'
 #
-#  [*images_panel*]
-#    (optional) Enabled panel for images.
-#    Valid values are 'legacy' and 'angular'
-#    Defaults to 'legacy'
-#
 #  [*create_image_defaults*]
 #    (optional) A dictionary of default settings for create image modal.
 #    Defaults to undef - will not add entry to local settings.
@@ -545,6 +540,12 @@
 #    (optional) Enable the use of the system scope token on per-service basis.
 #    Defaults to undef
 #
+# DEPRECATED PARAMETERS
+#
+#  [*images_panel*]
+#    (optional) Enabled panel for images.
+#    Defaults to undef
+#
 # === Examples
 #
 #  class { 'horizon':
@@ -634,7 +635,6 @@ class horizon(
   $available_themes                    = false,
   $default_theme                       = false,
   $password_autocomplete               = 'off',
-  $images_panel                        = 'legacy',
   $create_image_defaults               = undef,
   $password_retrieve                   = false,
   $disable_password_reveal             = false,
@@ -657,6 +657,8 @@ class horizon(
   $horizon_upload_mode                 = undef,
   $default_boot_source                 = undef,
   $system_scope_services               = undef,
+  # DEPRECATED PARAMETERS
+  $images_panel                        = undef,
 ) inherits horizon::params {
 
   include horizon::deps
@@ -680,6 +682,10 @@ class horizon(
   validate_legacy(Boolean, 'validate_bool', $websso_choices_hide_keystone)
   validate_legacy(Boolean, 'validate_bool', $websso_default_redirect)
 
+  if $images_panel {
+    warning('The images_panel parameter has been deprecated and has no effect.')
+  }
+
   if $cache_server_url and $cache_server_ip {
     fail('Only one of cache_server_url or cache_server_ip can be set.')
   }
@@ -762,7 +768,6 @@ class horizon(
 
   validate_legacy(Hash, 'validate_hash', $api_versions)
   validate_legacy(Enum['on', 'off'], 'validate_re', $password_autocomplete, [['^on$', '^off$']])
-  validate_legacy(Enum['legacy', 'angular'], 'validate_re', $images_panel, [['^legacy$', '^angular$']])
   validate_legacy(Stdlib::Absolutepath, 'validate_absolute_path', $root_path)
 
   if $manage_memcache_package {

releasenotes/notes/deprecate-images-panel-6c22100afadedbd4.yaml

@@ -0,0 +1,5 @@
+---
+deprecations:
+  - |
+    The ``horizon::images_panel`` parameter has been deprecated and has no
+    effect.

spec/classes/horizon_init_spec.rb

@@ -67,7 +67,6 @@ describe 'horizon' do
           "LOGIN_REDIRECT_URL = '#{platforms_params[:root_url]}/'",
           "ALLOWED_HOSTS = ['some.host.tld', ]",
           'HORIZON_CONFIG["password_autocomplete"] = "off"',
-          'HORIZON_CONFIG["images_panel"] = "legacy"',
           "SECRET_KEY = 'elj1IWiLoWHgcyYxFVLj7cM5rGOOxWl0'",
           'OPENSTACK_KEYSTONE_URL = "http://127.0.0.1:5000"',
           'OPENSTACK_KEYSTONE_DEFAULT_ROLE = "member"',
@@ -139,7 +138,6 @@ describe 'horizon' do
           ],
           :default_theme                    => 'default',
           :password_autocomplete            => 'on',
-          :images_panel                     => 'angular',
           :create_image_defaults            => {'image_visibility' => 'private'},
           :password_retrieve                => true,
           :enable_secure_proxy_ssl_header   => true,
@@ -161,7 +159,6 @@ describe 'horizon' do
           "OPENSTACK_KEYSTONE_MULTIDOMAIN_SUPPORT = True",
           "OPENSTACK_KEYSTONE_DEFAULT_DOMAIN = 'domain.tld'",
           'HORIZON_CONFIG["password_autocomplete"] = "on"',
-          'HORIZON_CONFIG["images_panel"] = "angular"',
           "SECRET_KEY = 'elj1IWiLoWHgcyYxFVLj7cM5rGOOxWl0'",
           "        'OPTIONS': {",
           "            'DEAD_RETRY': 1,",

templates/local_settings.py.erb

@@ -190,10 +190,6 @@ HORIZON_CONFIG["disable_password_reveal"] = True
 HORIZON_CONFIG["enforce_password_check"] = True
 <% end -%>
 
-# Configure enabled image panel. It can be legacy or angular.
-#HORIZON_CONFIG["images_panel"] = "legacy"
-HORIZON_CONFIG["images_panel"] = "<%= @images_panel %>"
-
 LOCAL_PATH = os.path.dirname(os.path.abspath(__file__))
 
 # Set custom secret key: