From b6a226e6f44441b89475ea2589c8ad6f18a824d4 Mon Sep 17 00:00:00 2001
From: Alexander Kireev <ak.chatman.media@gmail.com>
Date: Fri, 3 Jul 2026 06:46:11 +0700
Subject: [PATCH] Fix sign loss when scanning negative sexagesimal scalars

ScalarScanner#tokenize only applied the leading minus/plus to the
first colon-separated segment (via String#to_i/#to_f), so a value
like "-190:20:30" came out as -682770 instead of -685230 because the
20 and 30 parts kept their positive sign. Strip the sign once up
front and apply it to the final sum instead, matching the yaml.org
sexagesimal spec (and what PyYAML does). Added regression tests for
the negative int and float cases.
---
 lib/psych/scalar_scanner.rb       | 10 ++++++----
 test/psych/test_scalar_scanner.rb |  8 ++++++++
 2 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/lib/psych/scalar_scanner.rb b/lib/psych/scalar_scanner.rb
index 68e17ecf..c5cb0c1e 100644
--- a/lib/psych/scalar_scanner.rb
+++ b/lib/psych/scalar_scanner.rb
@@ -92,17 +92,19 @@ def tokenize string
           @symbol_cache[string] = class_loader.symbolize(string.sub(/^:/, ''))
         end
       elsif string.match?(/^[-+]?[0-9][0-9_]*(:[0-5]?[0-9]){1,2}$/)
+        sign = string.start_with?('-') ? -1 : 1
         i = 0
-        string.split(':').each_with_index do |n,e|
+        string.delete_prefix('-').delete_prefix('+').split(':').each_with_index do |n,e|
           i += (n.to_i * 60 ** (e - 2).abs)
         end
-        i
+        i * sign
       elsif string.match?(/^[-+]?[0-9][0-9_]*(:[0-5]?[0-9]){1,2}\.[0-9_]*$/)
+        sign = string.start_with?('-') ? -1 : 1
         i = 0
-        string.split(':').each_with_index do |n,e|
+        string.delete_prefix('-').delete_prefix('+').split(':').each_with_index do |n,e|
           i += (n.to_f * 60 ** (e - 2).abs)
         end
-        i
+        i * sign
       elsif string.match?(FLOAT)
         if string.match?(/\A[-+]?\.\Z/)
           string
diff --git a/test/psych/test_scalar_scanner.rb b/test/psych/test_scalar_scanner.rb
index bc6a74ad..fbaa6b26 100644
--- a/test/psych/test_scalar_scanner.rb
+++ b/test/psych/test_scalar_scanner.rb
@@ -105,6 +105,14 @@ def test_scan_sexagesimal_int
       assert_equal 685230, ss.tokenize('190:20:30')
     end
 
+    def test_scan_negative_sexagesimal_int
+      assert_equal(-685230, ss.tokenize('-190:20:30'))
+    end
+
+    def test_scan_negative_sexagesimal_float
+      assert_equal(-685230.15, ss.tokenize('-190:20:30.15'))
+    end
+
     def test_scan_float
       assert_equal 1.2, ss.tokenize('1.2')
     end