Feature #14153: [PATCH] resurrection of # -*- warn_past_scope: true -*-

• Status: Open
• Assignee: -
• Target version: -

[shyouhei (Shyouhei Urabe)]

From 2addeedcf8838dc15d127fffd888962b34879439 Mon Sep 17 00:00:00 2001
From: "Urabe, Shyouhei" <[e-mail]>
Date: Mon, 4 Dec 2017 19:28:55 +0900
Subject: [PATCH] resurrection of # -*- warn_past_scope: true -*-

I understand this feature was killed due to [Bug #10661].

However sometimes i _do_ want to check variable name collisions.

Please consider this feature again, with default off; no warning shall
be emitted unless theere are the dedicated magic comment in the source
code.

Signed-off-by: Urabe, Shyouhei <[e-mail]>
---
 parse.y | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/parse.y b/parse.y
index 03b9ed992e..a4a31af5e0 100644
--- a/parse.y
+++ b/parse.y
@@ -37,7 +37,7 @@
 #include "probes.h"
 
 #ifndef WARN_PAST_SCOPE
-# define WARN_PAST_SCOPE 0
+# define WARN_PAST_SCOPE 1
 #endif
 
 #define TAB_WIDTH 8
-- 
2.15.1

[shyouhei (Shyouhei Urabe)]

• Related to Bug #10661: The "possible reference to past scope" warning is quite frustrating and is forcing me to change my variable names from what I want added

[shyouhei (Shyouhei Urabe)]

This patch works like this:

% ./ruby --disable-gems -w -ve '[1, 2, 3].sample.tap { |rand| puts "Random value: #{rand}" }; puts "Another random value: #{rand}"'
ruby 2.5.0dev (2017-12-04 warn_past_scope 61011) [x86_64-darwin15]
Random value: 3
Another random value: 0.25989520023218615
%
%
% ./ruby --disable-gems -w -ve '# warn_past_scope: true' -e '[1, 2, 3].sample.tap { |rand| puts "Random value: #{rand}" }; puts "Another random value: #{rand}"'
ruby 2.5.0dev (2017-12-04 warn_past_scope 61011) [x86_64-darwin15]
-e:2: warning: possible reference to past scope - rand
Random value: 2
Another random value: 0.5832209137869108
%

[shevegen (Robert A. Heiler)]

I have no pro or con opinion so I will not comment on the suggestion.

I have one question though, apologies for a bit of side tracking:

• Can this be combined with other comment options such as "# frozen_string_literal: true"

?

Perhaps it may not apply as your example is only commandline but
I wanted to ask just in case anyone may want to combine more
than one option, for whatever reason, into the .rb file at hand.

[marcandre (Marc-Andre Lafortune)]

Seems to me to be more appropriate as a Rubocop cop.

[shyouhei (Shyouhei Urabe)]

@shevegen Yes. You can write multiple magic comments

• at once, like this:

    # -*- coding: utf-8; frozen_string_literal: true; warn_indent: true; warn_past_scope: true -*-
  

• or, line by line like this:

    # coding: utf-8
    # frozen_string_literal: true
    # warn_indent: true
    # warn_past_scope: true
  

[matz (Yukihiro Matsumoto)]

At least, I don't like the name warn_past_code. It's not intuitive.
And it may be better to be handled by Rubocop as Marc-Andre said.

Matz.

[dsferreira (Daniel Ferreira)]

Are we relying on rubocop as ruby’s official linter?

This question comes inline with my recent previous comment around core functionalities that I believe should be better managed as part of ruby API.
Debugger, Coverage, Unit tests, Benchmarks, Performance tools and yes Linter.
Missing Documentation here.
Maybe something else?