function save_changeset_post( $args = array() ) {

		$args = array_merge(
			array(
				'status'          => null,
				'title'           => null,
				'data'            => array(),
				'date_gmt'        => null,
				'user_id'         => get_current_user_id(),
				'starter_content' => false,
				'autosave'        => false,
			),
			$args
		);

		$changeset_post_id       = $this->changeset_post_id();
		$existing_changeset_data = array();
		if ( $changeset_post_id ) {
			$existing_status = get_post_status( $changeset_post_id );
			if ( 'publish' === $existing_status || 'trash' === $existing_status ) {
				return new WP_Error(
					'changeset_already_published',
					__( 'The previous set of changes has already been published. Please try saving your current set of changes again.' ),
					array(
						'next_changeset_uuid' => wp_generate_uuid4(),
					)
				);
			}

			$existing_changeset_data = $this->get_changeset_post_data( $changeset_post_id );
			if ( is_wp_error( $existing_changeset_data ) ) {
				return $existing_changeset_data;
			}
		}

		// Fail if attempting to publish but publish hook is missing.
		if ( 'publish' === $args['status'] && false === has_action( 'transition_post_status', '_wp_customize_publish_changeset' ) ) {
			return new WP_Error( 'missing_publish_callback' );
		}

		// Validate date.
		$now = gmdate( 'Y-m-d H:i:59' );
		if ( $args['date_gmt'] ) {
			$is_future_dated = ( mysql2date( 'U', $args['date_gmt'], false ) > mysql2date( 'U', $now, false ) );
			if ( ! $is_future_dated ) {
				return new WP_Error( 'not_future_date', __( 'You must supply a future date to schedule.' ) ); // Only future dates are allowed.
			}

			if ( ! $this->is_theme_active() && ( 'future' === $args['status'] || $is_future_dated ) ) {
				return new WP_Error( 'cannot_schedule_theme_switches' ); // This should be allowed in the future, when theme is a regular setting.
			}
			$will_remain_auto_draft = ( ! $args['status'] && ( ! $changeset_post_id || 'auto-draft' === get_post_status( $changeset_post_id ) ) );
			if ( $will_remain_auto_draft ) {
				return new WP_Error( 'cannot_supply_date_for_auto_draft_changeset' );
			}
		} elseif ( $changeset_post_id && 'future' === $args['status'] ) {

			// Fail if the new status is future but the existing post's date is not in the future.
			$changeset_post = get_post( $changeset_post_id );
			if ( mysql2date( 'U', $changeset_post->post_date_gmt, false ) <= mysql2date( 'U', $now, false ) ) {
				return new WP_Error( 'not_future_date', __( 'You must supply a future date to schedule.' ) );
			}
		}

		if ( ! empty( $is_future_dated ) && 'publish' === $args['status'] ) {
			$args['status'] = 'future';
		}

		// Validate autosave param. See _wp_post_revision_fields() for why these fields are disallowed.
		if ( $args['autosave'] ) {
			if ( $args['date_gmt'] ) {
				return new WP_Error( 'illegal_autosave_with_date_gmt' );
			} elseif ( $args['status'] ) {
				return new WP_Error( 'illegal_autosave_with_status' );
			} elseif ( $args['user_id'] && get_current_user_id() !== $args['user_id'] ) {
				return new WP_Error( 'illegal_autosave_with_non_current_user' );
			}
		}

		// The request was made via wp.customize.previewer.save().
		$update_transactionally = (bool) $args['status'];
		$allow_revision         = (bool) $args['status'];

		// Amend post values with any supplied data.
		foreach ( $args['data'] as $setting_id => $setting_params ) {
			if ( is_array( $setting_params ) && array_key_exists( 'value', $setting_params ) ) {
				$this->set_post_value( $setting_id, $setting_params['value'] ); // Add to post values so that they can be validated and sanitized.
			}
		}

		// Note that in addition to post data, this will include any stashed theme mods.
		$post_values = $this->unsanitized_post_values(
			array(
				'exclude_changeset' => true,
				'exclude_post_data' => false,
			)
		);
		$this->add_dynamic_settings( array_keys( $post_values ) ); // Ensure settings get created even if they lack an input value.

		/*
		 * Get list of IDs for settings that have values different from what is currently
		 * saved in the changeset. By skipping any values that are already the same, the
		 * subset of changed settings can be passed into validate_setting_values to prevent
		 * an underprivileged modifying a single setting for which they have the capability
		 * from being blocked from saving. This also prevents a user from touching of the
		 * previous saved settings and overriding the associated user_id if they made no change.
		 */
		$changed_setting_ids = array();
		foreach ( $post_values as $setting_id => $setting_value ) {
			$setting = $this->get_setting( $setting_id );

			if ( $setting && 'theme_mod' === $setting->type ) {
				$prefixed_setting_id = $this->get_stylesheet() . '::' . $setting->id;
			} else {
				$prefixed_setting_id = $setting_id;
			}

			$is_value_changed = (
				! isset( $existing_changeset_data[ $prefixed_setting_id ] )
				||
				! array_key_exists( 'value', $existing_changeset_data[ $prefixed_setting_id ] )
				||
				$existing_changeset_data[ $prefixed_setting_id ]['value'] !== $setting_value
			);
			if ( $is_value_changed ) {
				$changed_setting_ids[] = $setting_id;
			}
		}

		/**
		 * Fires before save validation happens.
		 *
		 * Plugins can add just-in-time {@see 'customize_validate_{$this->ID}'} filters
		 * at this point to catch any settings registered after `customize_register`.
		 * The dynamic portion of the hook name, `$this->ID` refers to the setting ID.
		 *
		 * @since 4.6.0
		 *
		 * @param WP_Customize_Manager $this WP_Customize_Manager instance.
		 */
		do_action( 'customize_save_validation_before', $this );

		// Validate settings.
		$validated_values      = array_merge(
			array_fill_keys( array_keys( $args['data'] ), null ), // Make sure existence/capability checks are done on value-less setting updates.
			$post_values
		);
		$setting_validities    = $this->validate_setting_values(
			$validated_values,
			array(
				'validate_capability' => true,
				'validate_existence'  => true,
			)
		);
		$invalid_setting_count = count( array_filter( $setting_validities, 'is_wp_error' ) );

		/*
		 * Short-circuit if there are invalid settings the update is transactional.
		 * A changeset update is transactional when a status is supplied in the request.
		 */
		if ( $update_transactionally && $invalid_setting_count > 0 ) {
			$response = array(
				'setting_validities' => $setting_validities,
				/* translators: %s: Number of invalid settings. */
				'message'            => sprintf( _n( 'Unable to save due to %s invalid setting.', 'Unable to save due to %s invalid settings.', $invalid_setting_count ), number_format_i18n( $invalid_setting_count ) ),
			);
			return new WP_Error( 'transaction_fail', '', $response );
		}

		// Obtain/merge data for changeset.
		$original_changeset_data = $this->get_changeset_post_data( $changeset_post_id );
		$data                    = $original_changeset_data;
		if ( is_wp_error( $data ) ) {
			$data = array();
		}

		// Ensure that all post values are included in the changeset data.
		foreach ( $post_values as $setting_id => $post_value ) {
			if ( ! isset( $args['data'][ $setting_id ] ) ) {
				$args['data'][ $setting_id ] = array();
			}
			if ( ! isset( $args['data'][ $setting_id ]['value'] ) ) {
				$args['data'][ $setting_id ]['value'] = $post_value;
			}
		}

		foreach ( $args['data'] as $setting_id => $setting_params ) {
			$setting = $this->get_setting( $setting_id );
			if ( ! $setting || ! $setting->check_capabilities() ) {
				continue;
			}

			// Skip updating changeset for invalid setting values.
			if ( isset( $setting_validities[ $setting_id ] ) && is_wp_error( $setting_validities[ $setting_id ] ) ) {
				continue;
			}

			$changeset_setting_id = $setting_id;
			if ( 'theme_mod' === $setting->type ) {
				$changeset_setting_id = sprintf( '%s::%s', $this->get_stylesheet(), $setting_id );
			}

			if ( null === $setting_params ) {
				// Remove setting from changeset entirely.
				unset( $data[ $changeset_setting_id ] );
			} else {

				if ( ! isset( $data[ $changeset_setting_id ] ) ) {
					$data[ $changeset_setting_id ] = array();
				}

				// Merge any additional setting params that have been supplied with the existing params.
				$merged_setting_params = array_merge( $data[ $changeset_setting_id ], $setting_params );

				// Skip updating setting params if unchanged (ensuring the user_id is not overwritten).
				if ( $data[ $changeset_setting_id ] === $merged_setting_params ) {
					continue;
				}

				$data[ $changeset_setting_id ] = array_merge(
					$merged_setting_params,
					array(
						'type'              => $setting->type,
						'user_id'           => $args['user_id'],
						'date_modified_gmt' => current_time( 'mysql', true ),
					)
				);

				// Clear starter_content flag in data if changeset is not explicitly being updated for starter content.
				if ( empty( $args['starter_content'] ) ) {
					unset( $data[ $changeset_setting_id ]['starter_content'] );
				}
			}
		}

		$filter_context = array(
			'uuid'          => $this->changeset_uuid(),
			'title'         => $args['title'],
			'status'        => $args['status'],
			'date_gmt'      => $args['date_gmt'],
			'post_id'       => $changeset_post_id,
			'previous_data' => is_wp_error( $original_changeset_data ) ? array() : $original_changeset_data,
			'manager'       => $this,
		);

		/**
		 * Filters the settings' data that will be persisted into the changeset.
		 *
		 * Plugins may amend additional data (such as additional meta for settings) into the changeset with this filter.
		 *
		 * @since 4.7.0
		 *
		 * @param array $data Updated changeset data, mapping setting IDs to arrays containing a $value item and optionally other metadata.
		 * @param array $context {
		 *     Filter context.
		 *
		 *     @type string               $uuid          Changeset UUID.
		 *     @type string               $title         Requested title for the changeset post.
		 *     @type string               $status        Requested status for the changeset post.
		 *     @type string               $date_gmt      Requested date for the changeset post in MySQL format and GMT timezone.
		 *     @type int|false            $post_id       Post ID for the changeset, or false if it doesn't exist yet.
		 *     @type array                $previous_data Previous data contained in the changeset.
		 *     @type WP_Customize_Manager $manager       Manager instance.
		 * }
		 */
		$data = apply_filters( 'customize_changeset_save_data', $data, $filter_context );

		// Switch theme if publishing changes now.
		if ( 'publish' === $args['status'] && ! $this->is_theme_active() ) {
			// Temporarily stop previewing the theme to allow switch_themes() to operate properly.
			$this->stop_previewing_theme();
			switch_theme( $this->get_stylesheet() );
			update_option( 'theme_switched_via_customizer', true );
			$this->start_previewing_theme();
		}

		// Gather the data for wp_insert_post()/wp_update_post().
		$post_array = array(
			// JSON_UNESCAPED_SLASHES is only to improve readability as slashes needn't be escaped in storage.
			'post_content' => wp_json_encode( $data, JSON_UNESCAPED_SLASHES | JSON_PRETTY_PRINT ),
		);
		if ( $args['title'] ) {
			$post_array['post_title'] = $args['title'];
		}
		if ( $changeset_post_id ) {
			$post_array['ID'] = $changeset_post_id;
		} else {
			$post_array['post_type']   = 'customize_changeset';
			$post_array['post_name']   = $this->changeset_uuid();
			$post_array['post_status'] = 'auto-draft';
		}
		if ( $args['status'] ) {
			$post_array['post_status'] = $args['status'];
		}

		// Reset post date to now if we are publishing, otherwise pass post_date_gmt and translate for post_date.
		if ( 'publish' === $args['status'] ) {
			$post_array['post_date_gmt'] = '0000-00-00 00:00:00';
			$post_array['post_date']     = '0000-00-00 00:00:00';
		} elseif ( $args['date_gmt'] ) {
			$post_array['post_date_gmt'] = $args['date_gmt'];
			$post_array['post_date']     = get_date_from_gmt( $args['date_gmt'] );
		} elseif ( $changeset_post_id && 'auto-draft' === get_post_status( $changeset_post_id ) ) {
			/*
			 * Keep bumping the date for the auto-draft whenever it is modified;
			 * this extends its life, preserving it from garbage-collection via
			 * wp_delete_auto_drafts().
			 */
			$post_array['post_date']     = current_time( 'mysql' );
			$post_array['post_date_gmt'] = '';
		}

		$this->store_changeset_revision = $allow_revision;
		add_filter( 'wp_save_post_revision_post_has_changed', array( $this, '_filter_revision_post_has_changed' ), 5, 3 );

		/*
		 * Update the changeset post. The publish_customize_changeset action
		 * will cause the settings in the changeset to be saved via
		 * WP_Customize_Setting::save().
		 */

		// Prevent content filters from corrupting JSON in post_content.
		$has_kses = ( false !== has_filter( 'content_save_pre', 'wp_filter_post_kses' ) );
		if ( $has_kses ) {
			kses_remove_filters();
		}
		$has_targeted_link_rel_filters = ( false !== has_filter( 'content_save_pre', 'wp_targeted_link_rel' ) );
		if ( $has_targeted_link_rel_filters ) {
			wp_remove_targeted_link_rel_filters();
		}

		// Note that updating a post with publish status will trigger WP_Customize_Manager::publish_changeset_values().
		if ( $changeset_post_id ) {
			if ( $args['autosave'] && 'auto-draft' !== get_post_status( $changeset_post_id ) ) {
				// See _wp_translate_postdata() for why this is required as it will use the edit_post meta capability.
				add_filter( 'map_meta_cap', array( $this, 'grant_edit_post_capability_for_changeset' ), 10, 4 );
				$post_array['post_ID']   = $post_array['ID'];
				$post_array['post_type'] = 'customize_changeset';
				$r                       = wp_create_post_autosave( wp_slash( $post_array ) );
				remove_filter( 'map_meta_cap', array( $this, 'grant_edit_post_capability_for_changeset' ), 10 );
			} else {
				$post_array['edit_date'] = true; // Prevent date clearing.
				$r                       = wp_update_post( wp_slash( $post_array ), true );

				// Delete autosave revision for user when the changeset is updated.
				if ( ! empty( $args['user_id'] ) ) {
					$autosave_draft = wp_get_post_autosave( $changeset_post_id, $args['user_id'] );
					if ( $autosave_draft ) {
						wp_delete_post( $autosave_draft->ID, true );
					}
				}
			}
		} else {
			$r = wp_insert_post( wp_slash( $post_array ), true );
			if ( ! is_wp_error( $r ) ) {
				$this->_changeset_post_id = $r; // Update cached post ID for the loaded changeset.
			}
		}

		// Restore removed content filters.
		if ( $has_kses ) {
			kses_init_filters();
		}
		if ( $has_targeted_link_rel_filters ) {
			wp_init_targeted_link_rel_filters();
		}

		$this->_changeset_data = null; // Reset so WP_Customize_Manager::changeset_data() will re-populate with updated contents.

		remove_filter( 'wp_save_post_revision_post_has_changed', array( $this, '_filter_revision_post_has_changed' ) );

		$response = array(
			'setting_validities' => $setting_validities,
		);

		if ( is_wp_error( $r ) ) {
			$response['changeset_post_save_failure'] = $r->get_error_code();
			return new WP_Error( 'changeset_post_save_failure', '', $response );
		}

		return $response;
	}