[ruby-core:56585] [ruby-trunk - Feature #8781] Use require_relative() instead of require() if possible

Issue #8781 has been updated by drbrain (Eric Hodel).


Even if a switch from require to require_relative is unsuitable for the standard library, we certainly can update the documentation for require and require_relative with recommended use and caveats.
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Feature #8781: Use require_relative() instead of require() if possible
https://bugs.ruby-lang.org/issues/8781#change-41120

Author: ko1 (Koichi Sasada)
Status: Open
Priority: Normal
Assignee: 
Category: lib
Target version: current: 2.1.0


I wrote a attached small script rrc.rb, stand for "RequireRelativeChecker".

This small script points out that require() can be replaced with require_relative().

"Detecting replace-able require()" algorithm is easy (and not perfect):
(1) If loaded file is at sub (or same) directory of requiring file.
(2) If requiring file foo.rb is at $LOAD_PATH, then check only foo/*.
See attached script for details.

This is a part of output.

####
/home/ko1/tmp/trunk/lib/ruby/2.1.0/cgi.rb:294: WARNING: Use require_relative() to require /home/ko1/tmp/trunk/lib/ruby/2.1.0/cgi/core.rb.
/home/ko1/tmp/trunk/lib/ruby/2.1.0/cgi.rb:295: WARNING: Use require_relative() to require /home/ko1/tmp/trunk/lib/ruby/2.1.0/cgi/cookie.rb.
/home/ko1/tmp/trunk/lib/ruby/2.1.0/date.rb:4: WARNING: Use require_relative() to require /home/ko1/tmp/trunk/lib/ruby/2.1.0/date/format.rb.
/home/ko1/tmp/trunk/lib/ruby/2.1.0/net/http.rb:1541: WARNING: Use require_relative() to require /home/ko1/tmp/trunk/lib/ruby/2.1.0/net/http/exceptions.rb.
/home/ko1/tmp/trunk/lib/ruby/2.1.0/net/http.rb:1543: WARNING: Use require_relative() to require /home/ko1/tmp/trunk/lib/ruby/2.1.0/net/http/header.rb.
/home/ko1/tmp/trunk/lib/ruby/2.1.0/net/http.rb:1545: WARNING: Use require_relative() to require /home/ko1/tmp/trunk/lib/ruby/2.1.0/net/http/generic_request.rb.
###

(all of warnings are attached)

How about to replace require() with require_relative() if it is possible?

Advantage:
* require_relative() is faster than require() especially with many gems.
* Easy to detect which file is loaded.

Disadvantage (incompatibility)
* We can't replace loading file with $LOAD_PATH trick.
(But I believe nobody expect such behavior)

(I also recommend other gem authors to  use require_relative)

Any comments?



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