Introduce the --with_attachments flag to control the behavior of atta…

…chments export, specifically in the case of --post__in

src/Export_Command.php

@@ -68,6 +68,10 @@ class Export_Command extends WP_CLI_Command {
 	 *
 	 * [--post__in=<pid>]
 	 * : Export all posts specified as a comma- or space-separated list of IDs.
+	 * Post's attachments won't be exported unless --with_attachments is specified.
+	 *
+	 * [--with_attachments]
+	 * : Force including attachments in case --post__in has been specified.
 	 *
 	 * [--start_id=<pid>]
 	 * : Export only posts with IDs greater than or equal to this post ID.
@@ -116,6 +120,7 @@ public function __invoke( $_, $assoc_args ) {
 			'category'          => NULL,
 			'post_status'       => NULL,
 			'post__in'          => NULL,
+			'with_attachments'  => TRUE, // or FALSE if user requested some post__in
 			'start_id'          => NULL,
 			'skip_comments'     => NULL,
 			'max_file_size'     => 15,
@@ -127,6 +132,10 @@ public function __invoke( $_, $assoc_args ) {
 			WP_CLI::error( '--stdout and --dir cannot be used together.' );
 		}
 
+		if (! empty( $assoc_args['post__in'] ) && ! empty( $assoc_args['with_attachments'] ) ) {
+			$defaults['with_attachments'] = FALSE;
+		}
+
 		$assoc_args = wp_parse_args( $assoc_args, $defaults );
 
 		$this->validate_args( $assoc_args );
@@ -315,6 +324,18 @@ private function check_post__in( $post__in ) {
 		return true;
 	}
 
+	private function check_with_attachments( $with ) {
+		if ( is_null( $with ) )
+			return true;
+
+		if ( (int) $with <> 0 && (int) $with <> 1 ) {
+			WP_CLI::warning( 'with_attachments needs to be 0 (no) or 1 (yes).' );
+			return false;
+		}
+		$this->export_args['with_attachments'] = (int) $with == 1 ;
+		return true;
+	}
+
 	private function check_start_id( $start_id ) {
 		if ( is_null( $start_id ) ) {
 			return true;

src/WP_Export_Query.php

@@ -140,8 +140,8 @@ public function posts() {
 	private function calculate_post_ids() {
 		global $wpdb;
 		if ( is_array( $this->filters['post_ids'] ) ) {
-			if ( getenv( 'WP_WITH_ATTACHMENT' ) ) {
-				$attachment_post_ids = $this->attachments_for_specific_post_types( $this->filters['post_ids'] );
+			if ( $this->filters['with_attachments'] ) {
+				$attachment_post_ids = $this->include_attachments_ids( $this->filters['post_ids'] );
 				$this->filters['post_ids'] = array_merge( $this->filters['post_ids'], $attachment_post_ids );
 			}
 			return $this->filters['post_ids'];
@@ -159,7 +159,9 @@ private function calculate_post_ids() {
 		$join = implode( ' ', array_filter( $this->joins ) );
 
 		$post_ids = $wpdb->get_col( "SELECT ID FROM {$wpdb->posts} AS p $join $where" );
-		$post_ids = array_merge( $post_ids, $this->attachments_for_specific_post_types( $post_ids ) );
+		if ( $this->filters['post_type'] ) {
+			$post_ids = array_merge( $post_ids, $this->include_attachments_ids( $post_ids ) );
+		}
 		return $post_ids;
 	}
 
@@ -264,7 +266,7 @@ private function category_where() {
 		$this->wheres[] = $wpdb->prepare( 'tr.term_taxonomy_id = %d', $category->term_taxonomy_id );
 	}
 
-	private function attachments_for_specific_post_types( $post_ids ) {
+	private function include_attachments_ids( $post_ids ) {
 		global $wpdb;
 		if ( ! $post_ids ) {
 			return array();