From b40f120f908f5774473554522660cea329013f3b Mon Sep 17 00:00:00 2001
From: Jean Boussier <jean.boussier@gmail.com>
Date: Fri, 24 Mar 2023 14:30:19 +0100
Subject: [PATCH] Generate native gems with `-fvisibility=hidden`

I recently ran into very nasty issues with dynamic symbols clashing between
two native gems.

I believe the overwhelming majority of native gems don't want to export
their symbols, so hidding them by default would make sense to me.
---
 .../lib/bundler/templates/newgem/ext/newgem/extconf-c.rb.tt   | 2 ++
 bundler/lib/bundler/templates/newgem/ext/newgem/newgem.c.tt   | 2 +-
 bundler/lib/bundler/templates/newgem/rubocop.yml.tt           | 4 ++++
 3 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/bundler/lib/bundler/templates/newgem/ext/newgem/extconf-c.rb.tt b/bundler/lib/bundler/templates/newgem/ext/newgem/extconf-c.rb.tt
index e918063ddf68..1399b1ae719d 100644
--- a/bundler/lib/bundler/templates/newgem/ext/newgem/extconf-c.rb.tt
+++ b/bundler/lib/bundler/templates/newgem/ext/newgem/extconf-c.rb.tt
@@ -2,4 +2,6 @@
 
 require "mkmf"
 
+$CFLAGS << " -fvisibility=hidden "
+
 create_makefile(<%= config[:makefile_path].inspect %>)
diff --git a/bundler/lib/bundler/templates/newgem/ext/newgem/newgem.c.tt b/bundler/lib/bundler/templates/newgem/ext/newgem/newgem.c.tt
index 8177c4d20214..bcd5148569ea 100644
--- a/bundler/lib/bundler/templates/newgem/ext/newgem/newgem.c.tt
+++ b/bundler/lib/bundler/templates/newgem/ext/newgem/newgem.c.tt
@@ -2,7 +2,7 @@
 
 VALUE rb_m<%= config[:constant_array].join %>;
 
-void
+RUBY_FUNC_EXPORTED void
 Init_<%= config[:underscored_name] %>(void)
 {
   rb_m<%= config[:constant_array].join %> = rb_define_module(<%= config[:constant_name].inspect %>);
diff --git a/bundler/lib/bundler/templates/newgem/rubocop.yml.tt b/bundler/lib/bundler/templates/newgem/rubocop.yml.tt
index 9ecec788075a..4845a67bd569 100644
--- a/bundler/lib/bundler/templates/newgem/rubocop.yml.tt
+++ b/bundler/lib/bundler/templates/newgem/rubocop.yml.tt
@@ -9,5 +9,9 @@ Style/StringLiteralsInInterpolation:
   Enabled: true
   EnforcedStyle: double_quotes
 
+Style/GlobalVars:
+  Exclude:
+    - ext/**/extconf.rb
+
 Layout/LineLength:
   Max: 120