interfering with podcast plugin

I can reliably reproduce a bug wherein the use of the display-posts shortcode within a post will change the global post – and not reset it. Here’s my PR to fix it in the down-stream podcast plugin, but the problem really exists either in display-posts or in WP.

https://github.com/TheCraigHewitt/Seriously-Simple-Podcasting/pull/465

The symptom is that as soon as get_the_excerpt() is called within the podcast plugin, the post global is changed as evidenced by a call to get_the_ID() before and after get_the_excerpt. If I remove the shortcode from the body of the post – the post ID does not change.

I looked into the display-posts code and it certainly seems to be cleaning up after itself properly, which is why I ended up submitting the PR to SSP!