Backport pull request #17931 from jellyfin/release-12.z

Fix decimal point handling in version names

Original-merge: ad1bf20e8424fa6433409a57f6f055ec7c394910

Merged-by: crobibero <cody@robibe.ro>

Backported-by: Cody Robibero <cody@robibe.ro>

2 files changed, 61 insertions, 3 deletions

diff --git a/MediaBrowser.Controller/Entities/BaseItem.cs b/MediaBrowser.Controller/Entities/BaseItem.cs
index d030c8f420..70e7da8932 100644
--- a/MediaBrowser.Controller/Entities/BaseItem.cs
+++ b/MediaBrowser.Controller/Entities/BaseItem.cs
@@ -1411,7 +1411,8 @@ namespace MediaBrowser.Controller.Entities
         /// token shared by the descriptors but separated only by spaces (e.g. a common "2160p ") is
         /// kept in the label, falling back to a space only when no structural delimiter is shared. The
         /// separators mirror the version delimiters recognised by the naming layer (Emby.Naming
-        /// VideoFlagDelimiters).
+        /// VideoFlagDelimiters), except that a dot between digits is a decimal point rather than a
+        /// delimiter, so numeric version labels stay whole.
         /// </summary>
         /// <param name="fileNames">The version file names without extension; must contain at least one entry.</param>
         /// <returns>The shared prefix retreated to a separator boundary, or an empty string when none is shared.</returns>
@@ -1445,9 +1446,12 @@ namespace MediaBrowser.Controller.Entities
 
             if (!prefixIsWholeName)
             {
-                // Retreat to the last structural delimiter ('-', '_', '.').
+                // Retreat to the last structural delimiter ('-', '_', '.'), skipping dots that are
+                // decimal points within a number rather than delimiters (see IsDecimalPoint).
                 var cut = prefix.Length;
-                while (cut > 0 && Array.IndexOf(VersionDelimiters, prefix[cut - 1]) < 0)
+                while (cut > 0
+                    && (Array.IndexOf(VersionDelimiters, prefix[cut - 1]) < 0
+                        || IsDecimalPoint(prefix, cut - 1, fileNames)))
                 {
                     cut--;
                 }
@@ -1467,6 +1471,31 @@ namespace MediaBrowser.Controller.Entities
             return prefix;
         }
 
+        private static bool IsDecimalPoint(string prefix, int index, IReadOnlyList<string> fileNames)
+        {
+            if (index == 0 || prefix[index] != '.' || !char.IsDigit(prefix[index - 1]))
+            {
+                return false;
+            }
+
+            if (index + 1 < prefix.Length)
+            {
+                return char.IsDigit(prefix[index + 1]);
+            }
+
+            // The dot ends the prefix, so the character after it is the first one that differs between
+            // the versions: only a decimal point when every version continues the number.
+            for (var i = 0; i < fileNames.Count; i++)
+            {
+                if (fileNames[i].Length <= index + 1 || !char.IsDigit(fileNames[i][index + 1]))
+                {
+                    return false;
+                }
+            }
+
+            return true;
+        }
+
         public Task RefreshMetadata(CancellationToken cancellationToken)
         {
             return RefreshMetadata(new MetadataRefreshOptions(new DirectoryService(FileSystem)), cancellationToken);
diff --git a/tests/Jellyfin.Controller.Tests/Entities/BaseItemTests.cs b/tests/Jellyfin.Controller.Tests/Entities/BaseItemTests.cs
index f9b29e576b..f363968909 100644
--- a/tests/Jellyfin.Controller.Tests/Entities/BaseItemTests.cs
+++ b/tests/Jellyfin.Controller.Tests/Entities/BaseItemTests.cs
@@ -203,6 +203,17 @@ public class BaseItemTests
         "Blade Runner (1982) [EE by ADM] [480p HEVC AAC]",
         "[Final Cut] [1080p HEVC AAC]",
         "[EE by ADM] [480p HEVC AAC]")]
+    // Numeric version labels: the dot between the digits is a decimal point, not a delimiter, so the
+    // prefix retreats past it to the '-' instead of leaving "0" / "11".
+    [InlineData(
+        "Evangelion 1.0 You Are (Not) Alone (2007) - 1.0",
+        "Evangelion 1.0 You Are (Not) Alone (2007) - 1.11",
+        "1.0",
+        "1.11")]
+    // Numeric labels with no structural delimiter at all fall back to the space boundary.
+    [InlineData("Movie (2007) 1.0", "Movie (2007) 1.11", "1.0", "1.11")]
+    // A dot followed by a non-digit is still a delimiter, even after a digit.
+    [InlineData("Movie - Part 1.HDR", "Movie - Part 1.SDR", "HDR", "SDR")]
     public void GetMediaSourceName_CommonPrefix_Valid(string primaryName, string altName, string expectedPrimary, string expectedAlt)
     {
         var primaryPath = "/Shows/Demo/Season 01/" + primaryName + ".mkv";
@@ -234,6 +245,24 @@ public class BaseItemTests
     }
 
     [Fact]
+    public void GetCommonVersionPrefix_NumericLabels_KeepsWholeNumber()
+    {
+        // Three versions labelled "1.0", "1.01" and "1.11": the common prefix stops inside the version
+        // number, so it must retreat past the decimal point to the '-' delimiter.
+        string[] fileNames =
+        [
+            "Evangelion 1.0 You Are (Not) Alone (2007) - 1.0",
+            "Evangelion 1.0 You Are (Not) Alone (2007) - 1.01",
+            "Evangelion 1.0 You Are (Not) Alone (2007) - 1.11"
+        ];
+
+        var prefix = BaseItem.GetCommonVersionPrefix(fileNames);
+
+        Assert.Equal("Evangelion 1.0 You Are (Not) Alone (2007) -", prefix);
+        Assert.Equal(["1.0", "1.01", "1.11"], fileNames.Select(n => n[prefix.Length..].TrimStart(' ')));
+    }
+
+    [Fact]
     public void GetAlternateVersion_ReturnsMatchingLocalVersion()
     {
         var (primary, alt1, alt2) = SetupVersionGroup();