Another SearchParser update for an unlikely case

src/searchoperatorset.php

@@ -73,12 +73,19 @@ function regex() {
             $br[] = "[{$ch}]";
         }
         if (!empty($alnum)) {
-            $br[] = '(?:' . join("|", $alnum) . ')(?=[\s\(\)]|\z)';
+            $br[] = '(?:' . join("|", $alnum) . ')(?=[\s\(\)\[\]\{\}]|\z)';
         }
         $this->regex = '/\G(?:' . join("|", $br) . ')/s';
         return $this->regex;
     }
 
+    /** @param string $str
+     * @param int $pos
+     * @return bool */
+    static function safe_terminator($str, $pos = 0) {
+        return preg_match('/\G[\s\(\)\[\]\{\}]/', $str, $m, 0, $pos);
+    }
+
 
     /** @return SearchOperatorSet */
     static function simple_operators() {

src/searchparser.php

@@ -21,6 +21,14 @@ function __construct($str, $pos1 = 0, $pos2 = null) {
         $this->str = $str;
         $this->pos = $pos1;
         $this->len = $pos2 ?? strlen($str);
+
+        // unlikely: passed a substring that ends mid-word; need to be careful
+        if ($this->len < strlen($str)
+            && !SearchOperatorSet::safe_terminator($str, $this->len)
+            && ($this->len === 0 || !SearchOperatorSet::safe_terminator($str, $this->len - 1))) {
+            $this->str = substr($str, 0, $this->len);
+        }
+
         $this->utf8q = strpos($str, chr(0xE2)) !== false && is_valid_utf8($str);
         $this->set_span_and_pos(0);
     }

test/t_unit.php

@@ -802,6 +802,18 @@ function test_span_balanced_parens() {
         $sp = new SearchParser("a(b(c(d(e", 1, 5);
         $x = $sp->shift_balanced_parens();
         xassert_eqq($x, "(b(c");
+
+        $sp = new SearchParser("HIGHLIGHT:foobar");
+        $pe = $sp->parse_expression();
+        xassert_neqq($pe->op, null);
+        xassert_eqq($pe->op->type, "highlight");
+        xassert_eqq($pe->op->subtype, "foobar");
+
+        $sp = new SearchParser("HIGHLIGHT:foobar", 0, 11);
+        $pe = $sp->parse_expression();
+        xassert_neqq($pe->op, null);
+        xassert_eqq($pe->op->type, "highlight");
+        xassert_eqq($pe->op->subtype, "f");
     }
 
     function test_unpack_comparison() {