grep returns a warning

[JosiahParry]

The use of grep here returns a warning for long strings. I am uploading a tar.gz and accessing it using mime. Each time the bundle is accessed I get this warning.

I'm not too sure what is causing the message but it would be nice to be able to not have to run suppressWarnings()

Warning in grep(rfc2183, head, perl = TRUE) : PCRE error
        'match limit exceeded'
        for element 1

https://github.com/yihui/mime/blob/1763e0dcb72fb58d97bab97bb834fc71f1e012bc/R/parse.R#L24

[yihui]

Yes, we could just suppressWarnings() here: https://github.com/yihui/mime/blob/1763e0dcb72fb58d97bab97bb834fc71f1e012bc/R/parse.R#L118

but it would be nice to truly understand what the problem is. I don't know what this warning means or what the code is doing here (this part of code was written by @jeffreyhorner, who I believe has left the R community long time ago).