
Why does “% I” in a podcast title break some car media players? - elicash
https://www.reddit.com/r/gimlet/comments/bbyhv4/reply_all_140_the_roman_mars_mazda_virus/
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elicash
99% Invisible doesn't work in some Mazda cars. The person who wrote the code
could only say that the % sign had some meaning in the URL and that caused the
"heartbeat" to tell the car that something wasn't working and therefore to
restart.

But no understanding of why this happens to % I and not % with other letters.
Even % i -- the lowercase -- is fine.

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paulrpotts
Wow. I'm guessing the parsing of the .xml feed file is badly broken? If the
string was getting passed somehow as the first argument to something like
sprintf(), I could see a crash happening, but the first argument should be a
fixed format string, not incoming data.

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elicash
Weirdly, when they simply changed the title from "99% Invisible" to "99%
invisible" that solved it.

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paulrpotts
"% i" might(???) be interpreted as "print a decimal number without including
the sign," where "% I" is (I think?) not a valid format string. This is pretty
speculative though. And it still doesn't make a lot of sense to me that part
of the file name would be interpreted as a format string.

~~~
elicash
This thread didn't get much attention, but since you chimed in I thought you
would be interested in how this got figured out in the comments here:
[https://www.reddit.com/r/gimlet/comments/bdxht4/hey_its_ben_...](https://www.reddit.com/r/gimlet/comments/bdxht4/hey_its_ben_from_the_reply_all_episode_140_i_have/)

