Fix bz 64373. Ensure tag file unpacked from WAR can be found.

Fixes https://bz.apache.org/bugzilla/show_bug.cgi?id=64373
Patch provided by Karl von Randow

java/org/apache/jasper/compiler/TagLibraryInfoImpl.java

@@ -313,6 +313,7 @@ private TagInfo createTagInfo(TagXml tagXml) throws JasperException {
                 tagXml.hasDynamicAttributes());
     }
 
+    @SuppressWarnings("null") // Impossible for path to be null at warning
     private TagFileInfo createTagFileInfo(TagFileXml tagFileXml, Jar jar) throws JasperException {
 
         String name = tagFileXml.getName();
@@ -325,6 +326,13 @@ private TagFileInfo createTagFileInfo(TagFileXml tagFileXml, Jar jar) throws Jas
             err.jspError("jsp.error.tagfile.illegalPath", path);
         }
 
+        if (jar == null && path.startsWith("/META-INF/tags")) {
+            // This is a tag file that was packaged in a JAR that has been
+            // unpacked into /WEB-INF/classes (probably by an IDE). Adjust the
+            // path accordingly.
+            path = "/WEB-INF/classes" + path;
+        }
+
         TagInfo tagInfo =
                 TagFileProcessor.parseTagFileDirectives(parserController, name, path, jar, this);
         return new TagFileInfo(name, path, tagInfo);

test/org/apache/jasper/compiler/TestTagLibraryInfoImpl.java

@@ -40,4 +40,19 @@ public void testRelativeTldLocation() throws Exception {
         Assert.assertEquals(HttpServletResponse.SC_OK, rc);
     }
 
+
+    /*
+     * https://bz.apache.org/bugzilla/show_bug.cgi?id=64373
+     */
+    @Test
+    public void testTldFromExplodedWar() throws Exception {
+        getTomcatInstanceTestWebapp(false, true);
+
+        ByteChunk res = new ByteChunk();
+
+        int rc = getUrl("http://localhost:" + getPort() +
+                "/test/bug6nnnn/bug64373.jsp", res, null);
+        Assert.assertEquals(HttpServletResponse.SC_OK, rc);
+    }
+
 }

test/webapp/WEB-INF/classes/META-INF/bug64373.tld

@@ -0,0 +1,31 @@
+<?xml version="1.0" encoding="UTF-8" ?>
+<!--
+  Licensed to the Apache Software Foundation (ASF) under one or more
+  contributor license agreements.  See the NOTICE file distributed with
+  this work for additional information regarding copyright ownership.
+  The ASF licenses this file to You under the Apache License, Version 2.0
+  (the "License"); you may not use this file except in compliance with
+  the License.  You may obtain a copy of the License at
+
+      http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+--><taglib xmlns="http://java.sun.com/xml/ns/javaee"
+      xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+      xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
+      http://java.sun.com/xml/ns/javaee/web-jsptaglibrary_2_1.xsd"
+      version="2.1">
+  <tlib-version>1.0</tlib-version>
+  <short-name>bug64373</short-name>
+  <uri>http://tomcat.apache.org/bug64373</uri>
+
+  <tag-file>
+    <name>bug64373</name>
+    <path>/META-INF/tags/bug64373.tag</path>
+  </tag-file>
+
+</taglib>

test/webapp/WEB-INF/classes/META-INF/tags/bug64373.tag

@@ -0,0 +1,17 @@
+<%--
+ Licensed to the Apache Software Foundation (ASF) under one or more
+  contributor license agreements.  See the NOTICE file distributed with
+  this work for additional information regarding copyright ownership.
+  The ASF licenses this file to You under the Apache License, Version 2.0
+  (the "License"); you may not use this file except in compliance with
+  the License.  You may obtain a copy of the License at
+
+      http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+--%><%@ tag %><%@
+tag body-content="empty" %><p>OK</p>

test/webapp/bug6nnnn/bug64373.jsp

@@ -0,0 +1,23 @@
+<%--
+ Licensed to the Apache Software Foundation (ASF) under one or more
+  contributor license agreements.  See the NOTICE file distributed with
+  this work for additional information regarding copyright ownership.
+  The ASF licenses this file to You under the Apache License, Version 2.0
+  (the "License"); you may not use this file except in compliance with
+  the License.  You may obtain a copy of the License at
+
+      http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+--%>
+<%@ taglib uri="http://tomcat.apache.org/bug64373" prefix="bugs" %>
+<html>
+  <head><title>Bug 64373 test case</title></head>
+  <body>
+    <bugs:bug64373 />
+  </body>
+</html>

webapps/docs/changelog.xml

@@ -127,6 +127,11 @@
         Add more descriptive error message in DefaultServlet for SC_NOT_FOUND.
         (michaelo)
       </add>
+      <fix>
+        <bug>64373</bug>: When a tag file is packaged in a WAR and then that WAR
+        is unpacked in <code>/WEB-INF/classes</code> ensure that the tag file
+        can still be found. Patch provided by Karl von Randow. (markt)
+      </fix>
     </changelog>
   </subsection>
   <subsection name="Web applications">