length shall not count when it sees nullc

core/vdbe/execute.rs

@@ -8012,8 +8012,12 @@ impl Value {
     pub fn exec_length(&self) -> Self {
         match self {
             Value::Text(t) => {
-                // Count Unicode scalar values (characters)
-                Value::Integer(t.as_str().chars().count() as i64)
+                let s = t.as_str();
+                let len_before_null = s.find('\0').map_or_else(
+                    || s.chars().count(),
+                    |null_pos| s[..null_pos].chars().count(),
+                );
+                Value::Integer(len_before_null as i64)
             }
             Value::Integer(_) | Value::Float(_) => {
                 // For numbers, SQLite returns the length of the string representation

testing/scalar-functions.test

@@ -939,6 +939,11 @@ do_execsql_test parse-large-integral-numeric-string-as-number {
   SELECT (-104614899632619 || 45597) > CAST(0 AS NUMERIC);
 } {0}
 
+# https://github.com/tursodatabase/turso/issues/3317
+do_execsql_test length-999123 {
+  select length('a' || char(0) || 'b');
+} {1}
+
 # TODO: sqlite seems not enable soundex() by default unless build it with SQLITE_SOUNDEX enabled.
 # do_execsql_test soundex-text {
 #  select soundex('Pfister'), soundex('husobee'), soundex('Tymczak'), soundex('Ashcraft'), soundex('Robert'), soundex('Rupert'), soundex('Rubin'), soundex('Kant'), soundex('Knuth'), soundex('x'), soundex('');