From 6cb43f74c4ecea801573b403df1d28ee28f791fb Mon Sep 17 00:00:00 2001
From: Harsh Kashyap <harsh.kashyap2001@gmail.com>
Date: Fri, 31 Jul 2026 09:21:21 +0530
Subject: [PATCH] fix(common,internal): round instead of truncate in
 normalize_overlapped_percent (closes #17418) (#17452)

---
 internal/ingestion/component/chunker/token_test.go |  8 ++++++++
 internal/ingestion/component/schema/chunker.go     | 12 ++++++++++--
 2 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/internal/ingestion/component/chunker/token_test.go b/internal/ingestion/component/chunker/token_test.go
index bb0c432ff2..c3cdff1e25 100644
--- a/internal/ingestion/component/chunker/token_test.go
+++ b/internal/ingestion/component/chunker/token_test.go
@@ -395,7 +395,11 @@ func TestNormalizeOverlappedPercent(t *testing.T) {
 	}{
 		{"zero", 0, 0},
 		{"fraction 0.1 -> 10", 0.1, 10},
+		{"fraction 0.29 -> 29 (round, was 28 trunc)", 0.29, 29},
+		{"fraction 0.3 -> 30", 0.3, 30},
 		{"fraction 0.5 -> 50", 0.5, 50},
+		{"fraction 0.57 -> 57 (round, was 56 trunc)", 0.57, 57},
+		{"fraction 0.93 -> 90 (clamp after round)", 0.93, 90},
 		{"fraction 0.95 -> 90 (clamp)", 0.95, 90},
 		{"percent 15", 15, 15},
 		{"int truncation 33.3 -> 33", 33.3, 33},
@@ -413,6 +417,8 @@ func TestNormalizeOverlappedPercent(t *testing.T) {
 		{"huge 1e300 -> 90", 1e300, 90},
 		{"huge -1e300 -> 0", -1e300, 0},
 		{"huge math.MaxFloat64 -> 90", math.MaxFloat64, 90},
+		{"huge math.MaxFloat64 +1 -> 90 (clamp pre-round)", math.MaxFloat64 + 1, 90},
+		{`numeric string fraction "0.29" -> 29`, "0.29", 29},
 	}
 	for _, tc := range cases {
 		t.Run(tc.name, func(t *testing.T) {
@@ -491,6 +497,8 @@ func TestTokenChunkerParam_ValidateOverlappedRange(t *testing.T) {
 		wantErr bool
 	}{
 		{"fraction 0.3 -> 30", 0.3, 30, false},
+		{"fraction 0.29 -> 29 (round, was 28 trunc)", 0.29, 29, false},
+		{"fraction 0.57 -> 57 (round, was 56 trunc)", 0.57, 57, false},
 		{"percent 0", 0, 0, false},
 		{"percent 30", 30, 30, false},
 		{"percent 90 (boundary)", 90, 90, false},
diff --git a/internal/ingestion/component/schema/chunker.go b/internal/ingestion/component/schema/chunker.go
index 6e9453dea8..826fdceabd 100644
--- a/internal/ingestion/component/schema/chunker.go
+++ b/internal/ingestion/component/schema/chunker.go
@@ -293,7 +293,12 @@ func clampOverlappedPercent(value float64) float64 {
 	if value > 90 {
 		value = 90
 	}
-	value = float64(int(value))
+	// Round rather than truncate so fraction inputs like 0.29 normalize
+	// to 29 (user expectation) rather than 28. Mirrors Python's
+	// common/float_utils.py:50-58 fix for #17418. We still clamp
+	// before rounding so out-of-int-range values (e.g. 1e300) land on
+	// 90, not an implementation-defined int.
+	value = math.Round(value)
 	return value
 }
 
@@ -308,7 +313,10 @@ func (p *TokenChunkerParam) Validate() error {
 	// rather than silently clamped — eliminating the latent footgun where a
 	// fraction passed to a struct bypassed normalization.
 	if v := p.OverlappedPercent; 0 < v && v < 1 {
-		p.OverlappedPercent = float64(int(v * 100))
+		// Round rather than truncate so fraction inputs like 0.29 normalize
+		// to 29 (user expectation) rather than 28. Mirrors Python's
+		// common/float_utils.py:50-58 fix for #17418.
+		p.OverlappedPercent = math.Round(v * 100)
 	}
 	switch p.DelimiterMode {
 	case "token_size", "delimiter":