From 37657c79b66994147e41f31139ceb9c0c840868f Mon Sep 17 00:00:00 2001
From: Jeremy Evans <code@jeremyevans.net>
Date: Tue, 24 Oct 2023 13:26:03 -0700
Subject: [PATCH] [ruby/uri] Make URI#to_s prepend relative path with / if
 there is a host or port

Otherwise, the path could be considered part of the host or port.

This is better than modifying the path to make it absolute when
a host or port is set.  We could also raise for invalid paths
when a host or port is set using check_path, but that results
in weird errors, and won't catch issues (such as ftp allowing a
relative path).

Fixes [Bug #19916]

https://github.com/ruby/uri/commit/ac32aa005b
---
 lib/uri/generic.rb       |  3 +++
 test/uri/test_generic.rb | 11 +++++++++++
 2 files changed, 14 insertions(+)

diff --git a/lib/uri/generic.rb b/lib/uri/generic.rb
index f3540a24bb..9ea2335cea 100644
--- a/lib/uri/generic.rb
+++ b/lib/uri/generic.rb
@@ -1364,6 +1364,9 @@ module URI
           str << ':'
           str << @port.to_s
         end
+        if (@host || @port) && !@path.empty? && !@path.start_with?('/')
+          str << '/'
+        end
         str << @path
         if @query
           str << '?'
diff --git a/test/uri/test_generic.rb b/test/uri/test_generic.rb
index e6619373c6..8209363b82 100644
--- a/test/uri/test_generic.rb
+++ b/test/uri/test_generic.rb
@@ -26,6 +26,17 @@ class URI::TestGeneric < Test::Unit::TestCase
     assert_equal "postgres:///foo", URI("postgres:///foo").to_s
     assert_equal "http:///foo", URI("http:///foo").to_s
     assert_equal "http:/foo", URI("http:/foo").to_s
+
+    uri = URI('rel_path')
+    assert_equal "rel_path", uri.to_s
+    uri.scheme = 'http'
+    assert_equal "http:rel_path", uri.to_s
+    uri.host = 'h'
+    assert_equal "http://h/rel_path", uri.to_s
+    uri.port = 8080
+    assert_equal "http://h:8080/rel_path", uri.to_s
+    uri.host = nil
+    assert_equal "http::8080/rel_path", uri.to_s
   end
 
   def test_parse