From 341e2524b97e02755382b165b1bdf2af16d6815b Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Sat, 28 Mar 2026 03:20:37 +0000
Subject: [PATCH] Fix array slice out-of-bounds panic with very negative
 indices

Agent-Logs-Url: https://github.com/mikefarah/yq/sessions/7c146762-d251-45fd-8555-2488f59fc57b

Co-authored-by: mikefarah <1151925+mikefarah@users.noreply.github.com>
---
 pkg/yqlib/operator_slice.go      | 11 +++++++++++
 pkg/yqlib/operator_slice_test.go | 16 ++++++++++++++++
 2 files changed, 27 insertions(+)

diff --git a/pkg/yqlib/operator_slice.go b/pkg/yqlib/operator_slice.go
index 24d1629d..e54a7918 100644
--- a/pkg/yqlib/operator_slice.go
+++ b/pkg/yqlib/operator_slice.go
@@ -80,13 +80,24 @@ func sliceArrayOperator(d *dataTreeNavigator, context Context, expressionNode *E
 		if relativeFirstNumber < 0 {
 			relativeFirstNumber = len(lhsNode.Content) + firstNumber
 		}
+		if relativeFirstNumber < 0 {
+			relativeFirstNumber = 0
+		} else if relativeFirstNumber > len(lhsNode.Content) {
+			relativeFirstNumber = len(lhsNode.Content)
+		}
 
 		relativeSecondNumber := secondNumber
 		if relativeSecondNumber < 0 {
 			relativeSecondNumber = len(lhsNode.Content) + secondNumber
+		}
+		if relativeSecondNumber < 0 {
+			relativeSecondNumber = 0
 		} else if relativeSecondNumber > len(lhsNode.Content) {
 			relativeSecondNumber = len(lhsNode.Content)
 		}
+		if relativeSecondNumber < relativeFirstNumber {
+			relativeSecondNumber = relativeFirstNumber
+		}
 
 		log.Debugf("calculateIndicesToTraverse: slice from %v to %v", relativeFirstNumber, relativeSecondNumber)
 
diff --git a/pkg/yqlib/operator_slice_test.go b/pkg/yqlib/operator_slice_test.go
index c4a6b783..33ce462f 100644
--- a/pkg/yqlib/operator_slice_test.go
+++ b/pkg/yqlib/operator_slice_test.go
@@ -98,6 +98,22 @@ var sliceArrayScenarios = []expressionScenario{
 			"D0, P[], (!!seq)::- cat1\n",
 		},
 	},
+	{
+		skipDoc:    true,
+		document:   `[cat, dog, frog]`,
+		expression: `.[-100:]`,
+		expected: []string{
+			"D0, P[], (!!seq)::- cat\n- dog\n- frog\n",
+		},
+	},
+	{
+		skipDoc:    true,
+		document:   `[cat, dog, frog]`,
+		expression: `.[:-100]`,
+		expected: []string{
+			"D0, P[], (!!seq)::[]\n",
+		},
+	},
 	{
 		description: "Slicing strings",
 		document:    `country: Australia`,