From cf5dd576e4c9c84d1823d4180aa1b6f1338bc0d4 Mon Sep 17 00:00:00 2001
From: Claude <noreply@anthropic.com>
Date: Sun, 27 Sep 2026 20:23:57 +0000
Subject: [PATCH] Rank real fuzzy matches above near-misses [patch]

Rank computed isMatch for every item but sorted on score alone. A short
near-miss such as "hell" avoids the skip and gap penalties a real match
inside a longer string pays, so it outscored "say hello to everyone" for
"hello". Sort on isMatch first, then score. Non-matches are still kept.

Fixes ktsu-dev/TextFilter#123

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01M9aefrfAYJpanQVrUuFpJh
---
 TextFilter.Test/TextFilterTests.cs | 19 +++++++++++++++++++
 TextFilter/TextFilter.cs           |  5 +++--
 2 files changed, 22 insertions(+), 2 deletions(-)

diff --git a/TextFilter.Test/TextFilterTests.cs b/TextFilter.Test/TextFilterTests.cs
index 66011f5..ed384b1 100644
--- a/TextFilter.Test/TextFilterTests.cs
+++ b/TextFilter.Test/TextFilterTests.cs
@@ -327,6 +327,25 @@ public void RankFuzzyReturnsCorrectRanking()
 		CollectionAssert.AreEqual(new List<string> { "hello", "hello world", "world" }, result);
 	}
 
+	[TestMethod]
+	[DataRow("hello", "hell", "say hello to everyone in the room")]
+	[DataRow("abc", "ab", "axxxxxxbxxxxxxc")]
+	[DataRow("readme", "read", "docs/ReleaseNotes/readme.md")]
+	[DataRow("config", "conf", "src/app/settings/config.json")]
+	public void RankPutsARealMatchAboveAHigherScoringNearMiss(string filter, string nearMiss, string match)
+	{
+		List<string> result = [.. TextFilter.Rank([nearMiss, match], filter)];
+		CollectionAssert.AreEqual(new List<string> { match, nearMiss }, result);
+	}
+
+	[TestMethod]
+	public void RankWithKeySelectorPutsARealMatchAboveAHigherScoringNearMiss()
+	{
+		List<(int Id, string Text)> items = [(1, "hell"), (2, "say hello to everyone in the room")];
+		List<(int Id, string Text)> result = [.. TextFilter.Rank(items, item => item.Text, "hello")];
+		CollectionAssert.AreEqual(new List<(int, string)> { (2, "say hello to everyone in the room"), (1, "hell") }, result);
+	}
+
 	[TestMethod]
 	public void RankEmptyStringsReturnsEmpty()
 	{
diff --git a/TextFilter/TextFilter.cs b/TextFilter/TextFilter.cs
index 65c8a36..36d6c02 100644
--- a/TextFilter/TextFilter.cs
+++ b/TextFilter/TextFilter.cs
@@ -201,7 +201,7 @@ public static IEnumerable<string> Rank(IEnumerable<string> strings, string fuzzy
 	/// <param name="keySelector">A function to extract the string key from an item.</param>
 	/// <param name="fuzzyFilter">The fuzzy filter pattern.</param>
 	/// <returns>The collection of items sorted by their match score.</returns>
-	/// <remarks>Uses fuzzy matching to rank the items by their match score.</remarks>
+	/// <remarks>Uses fuzzy matching to rank the items by their match score. Items that match the pattern always sort above items that don't, because a short near-miss can outscore a real match inside a longer string.</remarks>
 	public static IEnumerable<TItem> Rank<TItem>(IEnumerable<TItem> items, Func<TItem, string> keySelector, string fuzzyFilter)
 	{
 		Ensure.NotNull(items);
@@ -213,7 +213,8 @@ public static IEnumerable<TItem> Rank<TItem>(IEnumerable<TItem> items, Func<TIte
 			bool isMatch = IsMatch(keySelector(item), fuzzyFilter, out int score, TextFilterType.Fuzzy);
 			return (item, isMatch, score);
 		})
-		.OrderByDescending(t => t.score)
+		.OrderByDescending(t => t.isMatch)
+		.ThenByDescending(t => t.score)
 		.Select(t => t.item);
 	}