From 7121fe0b35b3f3c0ca46bfd23f28bf482e3dd524 Mon Sep 17 00:00:00 2001
From: Jakob Voss <voss@gbv.de>
Date: Mon, 28 Aug 2023 09:49:17 +0200
Subject: [PATCH] Fix diff for multiple fields of same identifier

---
 Changes           | 1 +
 lib/PICA/Patch.pm | 2 ++
 t/90-patch.t      | 2 ++
 3 files changed, 5 insertions(+)

diff --git a/Changes b/Changes
index a976e3f..775e5d5 100644
--- a/Changes
+++ b/Changes
@@ -3,6 +3,7 @@ Revision history for PICA::Data
 {{$NEXT}}
     - Add explicit PICA Patch parser and writer
     - Fix parsing plain $$ (#136)
+    - Fix diff for multiple fields of same identifier
     - Avoid circular dependency
 
 2.11 2023-08-18T05:19:26Z
diff --git a/lib/PICA/Patch.pm b/lib/PICA/Patch.pm
index 7f1221c..9b34d1e 100644
--- a/lib/PICA/Patch.pm
+++ b/lib/PICA/Patch.pm
@@ -30,6 +30,8 @@ sub sorted_fields {
         }
     }
 
+    $fields = [sort {cmp_fields($a, $b)} @$fields];
+
     return $fields;
 }
 
diff --git a/t/90-patch.t b/t/90-patch.t
index 23f63c7..0499b33 100644
--- a/t/90-patch.t
+++ b/t/90-patch.t
@@ -11,6 +11,8 @@ is_diff("001A \$x0\n002A \$x0", "001A \$x0\n002A \$y1",
     "- 002A \$x0\n+ 002A \$y1", 'changed field');
 is_diff("001A \$x0\n002A \$x0", "002A \$x0\n001A \$x0", '', 'compare sorted');
 
+is_diff("045Q/01 \$aXX.XX\n045Q/01 \$a38.10", "045Q/01 \$a38.10", '- 045Q/01 $aXX.XX', "sort before diff");
+
 is_patch("001A \$x.", "+ 001A \$y.", "001A \$x.\n001A \$y.", 'add same field id');
 is_patch("002A \$x.", "+ 001A \$y.", "001A \$y.\n002A \$x.", 'add before first field');
 is_patch("001A \$x.", "- 001A \$x.\n+ 001A \$y.", "001A \$y.", 'replace field id');