Issue #5104 - AbstractProxyServlet include incorrect protocol version…

… in Via header when accessed over H2.

Fixed HttpFields.computeField() removal loop.

Signed-off-by: Simone Bordet <simone.bordet@gmail.com>

jetty-http/src/main/java/org/eclipse/jetty/http/HttpFields.java

@@ -218,7 +218,7 @@ private <T> void computeField(T header, BiFunction<T, List<HttpField>, HttpField
                 }
                 // Remember and remove additional fields
                 found.add(f);
-                remove(i);
+                remove(i--);
             }
         }
 

jetty-http/src/test/java/org/eclipse/jetty/http/HttpFieldsTest.java

@@ -885,11 +885,12 @@ public void testComputeField()
         header.add(new HttpField("After", "value"));
         assertThat(header.stream().map(HttpField::toString).collect(Collectors.toList()), contains("Before: value", "Test: one", "After: value"));
 
-        header.add(new HttpField("Test", "extra"));
-        assertThat(header.stream().map(HttpField::toString).collect(Collectors.toList()), contains("Before: value", "Test: one", "After: value", "Test: extra"));
+        header.add(new HttpField("Test", "two"));
+        header.add(new HttpField("Test", "three"));
+        assertThat(header.stream().map(HttpField::toString).collect(Collectors.toList()), contains("Before: value", "Test: one", "After: value", "Test: two", "Test: three"));
 
         header.computeField("Test", (n, f) -> new HttpField("TEST", "count=" + f.size()));
-        assertThat(header.stream().map(HttpField::toString).collect(Collectors.toList()), contains("Before: value", "TEST: count=2", "After: value"));
+        assertThat(header.stream().map(HttpField::toString).collect(Collectors.toList()), contains("Before: value", "TEST: count=3", "After: value"));
 
         header.computeField("TEST", (n, f) -> null);
         assertThat(header.stream().map(HttpField::toString).collect(Collectors.toList()), contains("Before: value", "After: value"));