The Ruby readline extension was not compiled.

[silviali]

I'm new with the whole ruby and rbenv...
I was trying to install doing rbenv install 2.4.1
But get the following.
Did RUBY_CONFIGURE_OPTS=--with-readline-dir="$(brew --prefix readline)" rbenv install 2.4.1 and a few other things suggested in other post but to no avail... Please help.

ruby-build: use openssl from homebrew
Downloading ruby-2.4.1.tar.bz2...
-> https://cache.ruby-lang.org/pub/ruby/2.4/ruby-2.4.1.tar.bz2
Installing ruby-2.4.1...
ruby-build: use readline from homebrew
BUILD FAILED (OS X 10.12.4 using ruby-build 20170322)

Inspect or clean up the working tree at /var/folders/xq/zvy8gy656y155stcbh4gpzxr0000gp/T/ruby-build.20170416153259.57281
Results logged to /var/folders/xq/zvy8gy656y155stcbh4gpzxr0000gp/T/ruby-build.20170416153259.57281.log

Last 10 log lines:
The Ruby readline extension was not compiled.
ERROR: Ruby install aborted due to missing extensions
Configure options used:
  --prefix=/Users/silviali/.rbenv/versions/2.4.1
  --with-openssl-dir=/usr/local/opt/openssl
  --with-readline-dir=/usr/local/Cellar/readline/7.0.3_1
  CC=clang
  CFLAGS= -O3 -Wno-error=shorten-64-to-32 
  LDFLAGS=-L/Users/silviali/.rbenv/versions/2.4.1/lib 
  CPPFLAGS=-I/Users/silviali/.rbenv/versions/2.4.1/include 

[robmaurizi]

You may need to link readline... That appeared to be my issue.

Try brew install readline. When I ran that, it told me that readline was installed, but wasn't linked.

[nruth]

Did you install readline before building? It works for me on 10.13 (and previous versions) using the RUBY_CONFIGURE_OPTS snippet in the above post, though mine is in my shell profile rc file. I haven't needed to force-link readline for this to work.

[tesssie]

needed to do brew link readline --force

[mislav]

It should not be necessary to brew link readline --force. ruby-build will automatically link against Homebrew-installed readline even if readline itself wasn't globally "linked". Doing brew link readline --force can hurt installations of other software and that is exactly why Homebrew doesn't do it by default and discourages doing it entirely.

[icedtrees]

Is it feasible to require brew readline as a hard dependency on OSX? I feel like it would save a bunch of developer time from people running into this issue and having to look it up and figure out why it isn't working.

[mislav]

We automatically use readline from Homebrew whenever available.

ruby-build/bin/ruby-build

Lines 1010 to 1015 in f6e8dc1

	use_homebrew_readline() {
	if [[ "$RUBY_CONFIGURE_OPTS" != *--with-readline-dir=* ]]; then
	local libdir="$(brew --prefix readline 2>/dev/null || true)"
	if [ -d "$libdir" ]; then
	echo "ruby-build: using readline from homebrew"
	package_option ruby configure --with-readline-dir="$libdir"