iOS 11 includes Smart Punctuation, a feature that substitutes some forms of punctuation with those that are more typographically suitable (e.g., "straight" quotes with “smart” quotes). While this smart replacement is suited for writing, it can get in the way if you're a developer.
I recently installed the public beta of iOS 11 on my iPad Pro1 and hadn't realized that Smart Punctuation was not only present, it appears to be enabled by default. I was working on a remote server with Coda and couldn't figure out why some of the commands I was entering into Terminal weren't working. These were commands I'd used many times before, so it wasn't until I looked closely at my input that I realized the quotes and hypens I typed were not what I had expected.
Smart Punctuation can, thankfully, be disabled in Settings > General > Keyboards. I'd like to use it but with the amount of work I do on my iPad that requires using punctuation like straight quotes, I simply cannot if it's an all-or-nothing approach. I hope that there's some way for app developers to prevent smart punctuation from occurring, especially in apps like Coda or Working Copy, so that it can still be useful without the potential to cause problems. The most common bugs are always typos, and I doubt I'm the only person who is tripped up by Smart Punctuation.
I told myself I wouldn't install the beta on my iPad Pro. I caved. ↩