Ruby: added support for rack V3.

Ruby applications would fail to start if they were using rack v3

  2022/09/28 15:48:46 [alert] 0#80912 [unit] Ruby: Failed to parse rack script
  2022/09/28 15:48:46 [notice] 80911#80911 app process 80912 exited with code 1

This was due to a change in the rack API

Rack V2

  def self.load_file(path, opts = Server::Options.new)
    ...
    cfgfile.sub!(/^__END__\n.*\Z/m, '')
    app = new_from_string cfgfile, path

    return app, options
  end

Rack V3

  def self.load_file(path)
    ...

    return new_from_string(config, path)
  end

This patch handles _both_ the above APIs by correctly handling the cases
where we do and don't get an array returned from
nxt_ruby_rack_parse_script().

Closes: <https://github.com/nginx/unit/issues/755>
Tested-by: Andrew Clayton <a.clayton@nginx.com>
Reviewed-by: Andrew Clayton <a.clayton@nginx.com>
[ Andrew: Patch by Zhidao, commit message by me with input from Zhidao ]
Signed-off-by: Andrew Clayton <a.clayton@nginx.com>

1 files changed, 6 insertions, 1 deletions

diff --git a/src/ruby/nxt_ruby.c b/src/ruby/nxt_ruby.c
index 1b55e7ef..cc287e0e 100644
--- a/src/ruby/nxt_ruby.c
+++ b/src/ruby/nxt_ruby.c
@@ -480,12 +480,17 @@ nxt_ruby_rack_init(nxt_ruby_rack_init_t *rack_init)
 
     rackup = rb_protect(nxt_ruby_rack_parse_script,
                         (VALUE) (uintptr_t) rack_init, &state);
-    if (nxt_slow_path(TYPE(rackup) != T_ARRAY || state != 0)) {
+
+    if (nxt_slow_path(state != 0)) {
         nxt_ruby_exception_log(NULL, NXT_LOG_ALERT,
                                "Failed to parse rack script");
         return Qnil;
     }
 
+    if (TYPE(rackup) != T_ARRAY) {
+        return rackup;
+    }
+
     if (nxt_slow_path(RARRAY_LEN(rackup) < 1)) {
         nxt_alert(rack_init->task, "Ruby: Invalid rack config file");
         return Qnil;