The extra option including a space is splitted to execute the command.

[junaruga]

The ruby/openssl is using the rake-compiler. Here is my test on Fedora 37.

$ ruby -v
ruby 3.3.0dev (2023-05-22T03:58:17Z master bd786e7896) [x86_64-linux]

$ git clone https://github.com/ruby/openssl.git

$ cd openssl

Install the gems. The --standalone option is my favorite. :)

$ bundle install --standalone

$ bundle list | grep rake-compiler
  * rake-compiler (1.2.1)

Then the following command with --with-cflags='"-Wundef -Werror"' propagates the -Wundef -Werror to the compiler gcc command. Note that the MAKEFLAGS="V=1" is an option to print the compiler commands.

$ MAKEFLAGS="V=1" bundle exec rake compile -- --enable-debug --with-cflags='"-Wundef -Werror"'
...
/home/jaruga/.local/ruby-bd786e7896/bin/ruby -I. -r.rake-compiler-siteconf.rb ../../../../ext/openssl/extconf.rb -- --enable-debug --with-cflags="-Wundef -Werror"
...
gcc -I. -I/home/jaruga/.local/ruby-bd786e7896/include/ruby-3.3.0+0/x86_64-linux -I/home/jaruga/.local/ruby-bd786e7896/include/ruby-3.3.0+0/ruby/backward -I/home/jaruga/.local/ruby-bd786e7896/include/ruby-3.3.0+0 -I../../../../ext/openssl  -DRUBY_EXTCONF_H=\"extconf.h\"    -fPIC -Wundef -Werror   -o openssl_missing.o -c ../../../../ext/openssl/openssl_missing.c
...

However, the following command with --with-cflags='-Wundef -Werror' (without additional quotes) separates the --with-cflags=-Wundef from the -Werror. And it doesn't propagate the -Werror to the gcc command line.

$ MAKEFLAGS="V=1" bundle exec rake compile -- --enable-debug --with-cflags='-Wundef -Werror'
...
/home/jaruga/.local/ruby-bd786e7896/bin/ruby -I. -r.rake-compiler-siteconf.rb ../../../../ext/openssl/extconf.rb -- --enable-debug --with-cflags=-Wundef -Werror
...
gcc -I. -I/home/jaruga/.local/ruby-bd786e7896/include/ruby-3.3.0+0/x86_64-linux -I/home/jaruga/.local/ruby-bd786e7896/include/ruby-3.3.0+0/ruby/backward -I/home/jaruga/.local/ruby-bd786e7896/include/ruby-3.3.0+0 -I../../../../ext/openssl  -DRUBY_EXTCONF_H=\"extconf.h\"    -fPIC -Wundef   -o openssl_missing.o -c ../../../../ext/openssl/openssl_missing.c
...

Is it an expected behavior? Is it a bug?

Debug

I debugged with debug gem by adding the gem "debug" to the Gemfile of the ruby/opnessl. And set the breakpoint below.

$ diff -u extensiontask.rb.orig extensiontask.rb
--- extensiontask.rb.orig	2023-05-24 16:00:55.649111625 +0200
+++ extensiontask.rb	2023-05-24 16:31:21.646223039 +0200
@@ -214,6 +214,9 @@
           cmd.push(*extra_options)
         end
 
+        require 'debug'
+        binding.break
+
         chdir tmp_path do
           # FIXME: Rake is broken for multiple arguments system() calls.
           # Add current directory to the search path of Ruby

$ MAKEFLAGS="V=1" bundle exec rake compile -- --enable-debug --with-cflags='-Wundef -Werror'

I checked at the breakpoint binding.break.

(rdbg) f    # frame command
=> 218|         binding.break
=>#0	block {|t=<Rake::FileTask tmp/x86_64-linux/openssl/...|} in define_compile_tasks at ~/var/git/ruby/openssl/bundle/ruby/3.3.0+0/gems/rake-compiler-1.2.1/lib/rake/extensiontask.rb:218
(rdbg) p extra_options    # command
=> ["--", "--enable-debug", "--with-cflags=-Wundef -Werror"]
(rdbg) p cmd    # command
=> ["/home/jaruga/.local/ruby-bd786e7896/bin/ruby", "-I.", "-r.rake-compiler-siteconf.rb", #<Pathname:../../../../ext/openssl/extconf.rb>, "--", "--enable-debug", "--with-cflags=-Wundef -Werror"]
(rdbg) p cmd.join(' ')    # command
=> "/home/jaruga/.local/ruby-bd786e7896/bin/ruby -I. -r.rake-compiler-siteconf.rb ../../../../ext/openssl/extconf.rb -- --enable-debug --with-cflags=-Wundef -Werror"

So, it seems that cmd.join(' ') causes this issue.

rake-compiler/lib/rake/extensiontask.rb

Line 220 in 7fa360a

sh cmd.join(' ')

[kou]

Could you try 1.2.2?

[junaruga]

Thank you for fixing this issue and releasing the new version 1.2.2!

$ bundle list | grep rake-compiler
  * rake-compiler (1.2.2)

I confirmed that the following command propagates the -Wundef -Werror properly to the gcc command lines.

$ MAKEFLAGS="V=1" bundle exec rake compile -- --enable-debug --with-cflags='-Wundef -Werror'
...
/home/jaruga/.local/ruby-bd786e7896/bin/ruby -I. -r.rake-compiler-siteconf.rb ../../../../ext/openssl/extconf.rb -- --enable-debug --with-cflags=-Wundef -Werror
...
gcc -I. -I/home/jaruga/.local/ruby-bd786e7896/include/ruby-3.3.0+0/x86_64-linux -I/home/jaruga/.local/ruby-bd786e7896/include/ruby-3.3.0+0/ruby/backward -I/home/jaruga/.local/ruby-bd786e7896/include/ruby-3.3.0+0 -I../../../../ext/openssl  -DRUBY_EXTCONF_H=\"extconf.h\"    -fPIC -Wundef -Werror   -o openssl_missing.o -c ../../../../ext/openssl/openssl_missing.c
...

Note that the --with-cflags=-Wundef -Werror in the printed command line below doesn't have quotes. So, it may confuse users.

/home/jaruga/.local/ruby-bd786e7896/bin/ruby -I. -r.rake-compiler-siteconf.rb ../../../../ext/openssl/extconf.rb -- --enable-debug --with-cflags=-Wundef -Werror

And the following command with the additional quotes that succeeded with the rake-compiler 1.2.1 failed in the rake-compiler 1.2.2.

$ MAKEFLAGS="V=1" bundle exec rake compile -- --enable-debug --with-cflags='"-Wundef -Werror"'
mkdir -p tmp/x86_64-linux/openssl/3.3.0
cd tmp/x86_64-linux/openssl/3.3.0
/home/jaruga/.local/ruby-bd786e7896/bin/ruby -I. -r.rake-compiler-siteconf.rb ../../../../ext/openssl/extconf.rb -- --enable-debug --with-cflags="-Wundef -Werror"
checking for rb_io_maybe_wait(0, Qnil, Qnil, Qnil) in ruby/io.h... *** ../../../../ext/openssl/extconf.rb failed ***
Could not create Makefile due to some reason, probably lack of necessary
libraries and/or headers.  Check the mkmf.log file for more details.  You may
need configuration options.

Provided configuration options:
	--with-opt-dir
	--without-opt-dir
	--with-opt-include
	--without-opt-include=${opt-dir}/include
	--with-opt-lib
	--without-opt-lib=${opt-dir}/lib
	--with-make-prog
	--without-make-prog
	--srcdir=../../../../ext/openssl
	--curdir
	--ruby=/home/jaruga/.local/ruby-bd786e7896/bin/$(RUBY_BASE_NAME)
	--with-openssl-dir
	--without-openssl-dir
	--with-openssl-include
	--without-openssl-include=${openssl-dir}/include
	--with-openssl-lib
	--without-openssl-lib=${openssl-dir}/lib
	--with-kerberos-dir
	--without-kerberos-dir
	--with-kerberos-include
	--without-kerberos-include=${kerberos-dir}/include
	--with-kerberos-lib
	--without-kerberos-lib=${kerberos-dir}/lib
	--with-debug
	--without-debug
	--enable-debug
/home/jaruga/.local/ruby-bd786e7896/lib/ruby/3.3.0+0/mkmf.rb:480:in `try_do': The compiler failed to generate an executable file. (RuntimeError)
You have to install development tools first.

	from /home/jaruga/.local/ruby-bd786e7896/lib/ruby/3.3.0+0/mkmf.rb:573:in `try_link0'
	from /home/jaruga/.local/ruby-bd786e7896/lib/ruby/3.3.0+0/mkmf.rb:591:in `try_link'
	from /home/jaruga/.local/ruby-bd786e7896/lib/ruby/3.3.0+0/mkmf.rb:809:in `try_func'
	from /home/jaruga/.local/ruby-bd786e7896/lib/ruby/3.3.0+0/mkmf.rb:1110:in `block in have_func'
	from /home/jaruga/.local/ruby-bd786e7896/lib/ruby/3.3.0+0/mkmf.rb:983:in `block in checking_for'
	from /home/jaruga/.local/ruby-bd786e7896/lib/ruby/3.3.0+0/mkmf.rb:344:in `block (2 levels) in postpone'
	from /home/jaruga/.local/ruby-bd786e7896/lib/ruby/3.3.0+0/mkmf.rb:314:in `open'
	from /home/jaruga/.local/ruby-bd786e7896/lib/ruby/3.3.0+0/mkmf.rb:344:in `block in postpone'
	from /home/jaruga/.local/ruby-bd786e7896/lib/ruby/3.3.0+0/mkmf.rb:314:in `open'
	from /home/jaruga/.local/ruby-bd786e7896/lib/ruby/3.3.0+0/mkmf.rb:340:in `postpone'
	from /home/jaruga/.local/ruby-bd786e7896/lib/ruby/3.3.0+0/mkmf.rb:982:in `checking_for'
	from /home/jaruga/.local/ruby-bd786e7896/lib/ruby/3.3.0+0/mkmf.rb:1109:in `have_func'
	from ../../../../ext/openssl/extconf.rb:30:in `<main>'
rake aborted!
Command failed with status (1): [/home/jaruga/.local/ruby-bd786e7896/bin/ru...]
/home/jaruga/var/git/ruby/openssl/bundle/ruby/3.3.0+0/gems/rake-compiler-1.2.2/lib/rake/extensiontask.rb:218:in `block (2 levels) in define_compile_tasks'
/home/jaruga/var/git/ruby/openssl/bundle/ruby/3.3.0+0/gems/rake-compiler-1.2.2/lib/rake/extensiontask.rb:217:in `block in define_compile_tasks'
/home/jaruga/var/git/ruby/openssl/bundle/ruby/3.3.0+0/gems/rake-13.0.6/exe/rake:27:in `<top (required)>'
/home/jaruga/.local/ruby-bd786e7896/bin/bundle:25:in `load'
/home/jaruga/.local/ruby-bd786e7896/bin/bundle:25:in `<main>'
Tasks: TOP => compile => compile:x86_64-linux => compile:openssl:x86_64-linux => copy:openssl:x86_64-linux:3.3.0 => tmp/x86_64-linux/openssl/3.3.0/openssl.so => tmp/x86_64-linux/openssl/3.3.0/Makefile
(See full trace by running task with --trace)

I debugged with debug gem again. The mkmf.rb receives the "\"-Wundef -Werror\"". And I think this is a correct behavior.

@@ -2601,6 +2601,10 @@
     if (w = rbconfig['CC_WRAPPER']) and !w.empty? and !File.executable?(w)
       rbconfig['CC_WRAPPER'] = config['CC_WRAPPER'] = ''
     end
+
+    require 'debug'
+    binding.break
+
     $CFLAGS = with_config("cflags", arg_config("CFLAGS", config["CFLAGS"])).dup
     $CXXFLAGS = (with_config("cxxflags", arg_config("CXXFLAGS", config["CXXFLAGS"]))||'').dup
     $ARCH_FLAG = with_config("arch_flag", arg_config("ARCH_FLAG", config["ARCH_FLAG"])).dup

(rdbg) f    # frame command
=>2606|     binding.break
=>#0	MakeMakefile#init_mkmf(config={"DESTDIR"=>"", "MAJOR"=>"3", "MINOR"=>"3..., rbconfig={"DESTDIR"=>"", "MAJOR"=>"3", "MINOR"=>"3...) at ~/.local/ruby-bd786e7896/lib/ruby/3.3.0+0/mkmf.rb:2606
(rdbg) p with_config("cflags", arg_config("CFLAGS", config["CFLAGS"])).dup    # command
=> "\"-Wundef -Werror\""

[kou]

Note that the --with-cflags=-Wundef -Werror in the printed command line below doesn't have quotes. So, it may confuse users.

It's done by Rake: https://github.com/ruby/rake/blob/1d3579b01484a59bdf1a3e542662ea4ab7e79f7c/lib/rake/file_utils.rb#L80

If you think that we should improve this, please report it to Rake.

I think this is a correct behavior.

Right.

[junaruga]

If you think that we should improve this, please report it to Rake.

Thank you for checking the part causing the issue. I reported the issue on ruby/rake#501 at the rake project.