From dff828cdbe5e21554d33b16160bab9878879e458 Mon Sep 17 00:00:00 2001
From: Riley Bruins <ribru17@hotmail.com>
Date: Mon, 21 Jul 2025 21:44:21 -0700
Subject: [PATCH] fix(rust): prevent overflow in error message calculation

**Problem:** When encountering an invalid symbol at the beginning of the
file, the rust bindings attempt to index the character at position -1 of
the query source, which leads to an overflow and thus invalid character
index which causes a panic.

**Solution:** Bounds check the offset before performing the subtraction.
---
 crates/cli/src/tests/query_test.rs | 10 ++++++++++
 lib/binding_rust/lib.rs            |  2 +-
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/crates/cli/src/tests/query_test.rs b/crates/cli/src/tests/query_test.rs
index 5486a537..7c436ede 100644
--- a/crates/cli/src/tests/query_test.rs
+++ b/crates/cli/src/tests/query_test.rs
@@ -342,6 +342,16 @@ fn test_query_errors_on_invalid_symbols() {
                 message: "\"alternatives\"".to_string()
             }
         );
+        assert_eq!(
+            Query::new(&language, "fakefield: (identifier)").unwrap_err(),
+            QueryError {
+                row: 0,
+                offset: 0,
+                column: 0,
+                kind: QueryErrorKind::Field,
+                message: "\"fakefield\"".to_string()
+            }
+        );
     });
 }
 
diff --git a/lib/binding_rust/lib.rs b/lib/binding_rust/lib.rs
index 3ffd90c4..a4cea362 100644
--- a/lib/binding_rust/lib.rs
+++ b/lib/binding_rust/lib.rs
@@ -2446,7 +2446,7 @@ impl Query {
                 // Error types that report names
                 ffi::TSQueryErrorNodeType | ffi::TSQueryErrorField | ffi::TSQueryErrorCapture => {
                     let suffix = source.split_at(offset).1;
-                    let in_quotes = source.as_bytes()[offset - 1] == b'"';
+                    let in_quotes = offset > 0 && source.as_bytes()[offset - 1] == b'"';
                     let mut backslashes = 0;
                     let end_offset = suffix
                         .find(|c| {