An error occurred while installing thin (1.7.2)

Question

i tried to install the thin web server, version 1.7.2 but got an error

with the logs:

thin.c:359:10: error: implicit declaration of function 'thin_http_parser_has_error' is invalid in C99
[-Werror,-Wimplicit-function-declaration]
  return thin_http_parser_has_error(http) ? Qtrue : Qfalse;
         ^
thin.c:374:10: error: implicit declaration of function 'thin_http_parser_is_finished' is invalid in C99
[-Werror,-Wimplicit-function-declaration]
  return thin_http_parser_is_finished(http) ? Qtrue : Qfalse;
         ^
9 errors generated.
make: *** [thin.o] Error 1

make failed, exit code 2

Gem files will remain installed in
/Users/dorianmarie/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/gems/thin-1.7.2 for inspection.
Results logged to
/Users/dorianmarie/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/extensions/x86_64-darwin-19/2.7.0/thin-1.7.2/gem_make.out

An error occurred while installing thin (1.7.2), and Bundler cannot continue.
Make sure that `gem install thin -v '1.7.2' --source 'https://rubygems.org/'` succeeds before bundling.

Answer 1

disabling the error fixed it:

bundle config build.thin --with-cflags="-Wno-error=implicit-function-declaration"

Answer 2

The solution that worked for me was slightly different. I had to run the following for my specific gem version, using rbenv on Big Sur 11.3.1. I added a more in depth explanation of my particular error and solution here.

gem install thin -v '1.6.4' -- --with-cflags="-Wno-error=implicit-function-declaration"