I have recently determined through trial and error and process of elimination that Zemanta is responsible for adding extraneous HTML comments to my pre-formatted (with “pre” tags) PHP code that I have placed between “sourcecode” tags to activate WordPress.com’s built in programming code syntax highlighting.
Here is a screenshot (fig 1.) that demonstrates the problem:
See, all that green is what commented my code out and made it so it doesn’t display correctly.
I am not totally sure Zemanta is to blame, but it seems the most likely culprit. Here’s why:
Identified 3 possible suspects: Zemanta, WordPress.com proofreading, and pasting pre-formatted code in Visual view instead of HTML view.
Disabled Zemanta and retested – problem remained.
With Zemanta disabled, disabled proofreading as well. No change.
With Zemanta and proofreading disabled, went Edit>HTML View. In each instance where I had posted code, deleted all the code from in between “sourcecode” tags.
Re-copied and pasted code from each original PHP file. Re-tested: Worked! Syntax highlighting works properly now. Made multiple edits to both code and text, updated and viewed the post — Good to go every time.
Re-enabled Zemanta, made a test edit, saved and previewed the new post. Everything is messed up again! This is why I think Zemanta is the issue.
DO NOT, (under any circumstances) have Zemanta enabled if you have preformatted PHP code in your blog. Chances are, Zemanta will mess your code up and you will have to re-paste your code again. During my tests, I have had to paste all my sourcecode from scratch 3 times and let me tell you — it gets very tedious and wastes valueable time.
Always paste sourcecode in HTML view only.
These are my recommendations based on my personal experience with this issue. I’d love to hear from anyone else who is having similar issues. Please let me know if this solution worked for you!