Bug 239661 – [CMake] Could NOT find Ruby

• Status: NEW
• Component: CMake

[Michael Catanzaro]

We have some weird mystery with CMake's tests for Ruby:

-- Could NOT find Ruby (missing: Ruby_INCLUDE_DIR Ruby_LIBRARY Ruby_CONFIG_INCLUDE_DIR) (found suitable version "2.5.9", minimum required is "1.9")

This has been broken for as long as I remember, probably 5+ years or more. After CMake prints this line, it just... keeps going, with no apparent problems whatsoever. It seems like a harmless warning, but it's dumb and I'm curious what's going on.

[Fujii Hironori]

The warning means it founds ruby command, but ruby library.

There is a comment about this.

https://github.com/WebKit/WebKit/blob/c0fdd48006a448510939c08c02422208dfc98bdb/Source/cmake/WebKitCommon.cmake#L190,L192

>    # We cannot check for RUBY_FOUND because it is set only when the full package is installed and
>    # the only thing we need is the interpreter. Unlike Python, cmake does not provide a macro
>    # for finding only the Ruby interpreter.

FindRuby should have `COMPONENTS Interpreter` like FindPython.

https://cmake.org/cmake/help/latest/module/FindRuby.html
https://cmake.org/cmake/help/latest/module/FindPython.html

[Fujii Hironori]

FindRuby: Distinguish Interpreter and Development components (#20474) · Issues · CMake / CMake · GitLab
https://gitlab.kitware.com/cmake/cmake/-/issues/20474