Consume escaped subqueries correctly

Now that escaped sequences can have spaces, that needs to be handled in consumeSubQuery correctly.

The unescape -> escape step is a bit redundant. If perf critical we could have a method that consumes escape sequences without actually unescaping them. Or, we could refactor consumeSubQuery to parse into Evaluators directly.

But the rest is already pretty stringy, and users can keep parsed Evaluators for reuse, so am deeming OK for now.

Fixes issue noted in #2305

Author: jhy

src/main/java/org/jsoup/select/QueryParser.java

@@ -160,8 +160,7 @@ private String consumeSubQuery() {
             else if (tq.matches("["))
                 sq.append("[").append(tq.chompBalanced('[', ']')).append("]");
             else if (tq.matches("\\")) { // bounce over escapes
-                sq.append(tq.consume());
-                if (!tq.isEmpty()) sq.append(tq.consume());
+                sq.append(TokenQueue.escapeCssIdentifier(tq.consumeCssIdentifier()));
             } else
                 sq.append(tq.consume());
         }

src/test/java/org/jsoup/select/QueryParserTest.java

@@ -2,6 +2,7 @@
 
 import org.jsoup.Jsoup;
 import org.jsoup.nodes.Document;
+import org.jsoup.nodes.Element;
 import org.junit.jupiter.api.Test;
 
 import static org.jsoup.select.EvaluatorDebug.asElement;
@@ -182,4 +183,28 @@ public void exceptOnUnhandledEvaluator() {
         assertEquals("(Or (And (Id '#el')(AttributeWithValueContaining '[class*=child]'))(Class '.some-other-selector'))", sexpr("#el[class*=child], .some-other-selector"));
         assertEquals("(Or (And (AttributeWithValueContaining '[class*=child]')(Ancestor (Id '#parent')))(And (Class '.nested')(Ancestor (Class '.some-other-selector'))))", sexpr("#parent [class*=child], .some-other-selector .nested"));
     }
+
+    @Test void parsesEscapedSubqueries() {
+        String html = "<div class='-4a'>One</div> <div id='-4a'>Two</div>";
+        Document doc = Jsoup.parse(html);
+
+        String classQ = "div.-\\34 a";
+        Element div1 = doc.expectFirst(classQ);
+        assertEquals("One", div1.wholeText());
+
+        String idQ = "#-\\34 a";
+        Element div2 = doc.expectFirst(idQ);
+        assertEquals("Two", div2.wholeText());
+
+        String genClassQ = "html > body > div.-\\34 a";
+        assertEquals(genClassQ, div1.cssSelector());
+        assertSame(div1, doc.expectFirst(genClassQ));
+
+        String deepIdQ = "html > body > #-\\34 a";
+        assertEquals(idQ, div2.cssSelector());
+        assertSame(div2, doc.expectFirst(deepIdQ));
+
+        assertEquals("(ImmediateParentRun (Tag 'html')(Tag 'body')(And (Tag 'div')(Class '.-4a')))", sexpr(genClassQ));
+        assertEquals("(ImmediateParentRun (Tag 'html')(Tag 'body')(Id '#-4a'))", sexpr(deepIdQ));
+    }
 }