Created attachment 32400 [details]
Repeat build.xml

It seems like revision 1645615 broke the ant jasper task in 7.0.58 for taglibs.

Repeat:

 1) Download and unzip apache-tomcat-7.0.58.zip and apache-ant-1.9.4-bin.zip to a temporary directory.

 2) Put the following into a new file build.xml in the directory: (attached, based on http://tomcat.apache.org/tomcat-7.0-doc/jasper-howto.html#Web_Application_Compilation)

   <project>

     <import file="apache-tomcat-7.0.58/bin/catalina-tasks.xml"/>

     <target name="jspc">

       <jasper
                validateXml="false"
                uriroot="apache-tomcat-7.0.58/webapps/examples"
                webXmlFragment="tmp/WEB-INF/generated_web.xml"
                outputDir="tmp/WEB-INF/src" />

     </target>
   </project>

 3) Execute "apache-ant-1.9.4/bin/ant jspc" in the directory.

Expected result:

 Compiled output in tmp/WEB-INF

Actual result:

 Exception is thrown and only partial output to tmp/WEB-INF:

 jspc:
   [jasper] java.lang.NullPointerException
   [jasper] 	at org.apache.jasper.JspCompilationContext.getTldLocation(JspCompilationContext.java:618)
   [jasper] 	at org.apache.jasper.compiler.Parser.parseTaglibDirective(Parser.java:409)
   [jasper] 	at org.apache.jasper.compiler.Parser.parseDirective(Parser.java:475)
   [jasper] 	at org.apache.jasper.compiler.Parser.parseElements(Parser.java:1410)
   [jasper] 	at org.apache.jasper.compiler.Parser.parse(Parser.java:138)
   [jasper] 	at org.apache.jasper.compiler.ParserController.doParse(ParserController.java:242)
   [jasper] 	at org.apache.jasper.compiler.ParserController.parse(ParserController.java:102)
   [jasper] 	at org.apache.jasper.compiler.Compiler.generateJava(Compiler.java:199)
   [jasper] 	at org.apache.jasper.compiler.Compiler.compile(Compiler.java:374)
   [jasper] 	at org.apache.jasper.JspC.processFile(JspC.java:1213)
   [jasper] 	at org.apache.jasper.JspC.execute(JspC.java:1364)
   [jasper] 	at org.apache.tools.ant.UnknownElement.execute(UnknownElement.java:292)
   [jasper] 	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
   [jasper] 	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
   [jasper] 	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
   [jasper] 	at java.lang.reflect.Method.invoke(Method.java:606)
   [jasper] 	at org.apache.tools.ant.dispatch.DispatchUtils.execute(DispatchUtils.java:106)
   [jasper] 	at org.apache.tools.ant.Task.perform(Task.java:348)
   [jasper] 	at org.apache.tools.ant.Target.execute(Target.java:435)
   [jasper] 	at org.apache.tools.ant.Target.performTasks(Target.java:456)
   [jasper] 	at org.apache.tools.ant.Project.executeSortedTargets(Project.java:1393)
   [jasper] 	at org.apache.tools.ant.Project.executeTarget(Project.java:1364)
   [jasper] 	at org.apache.tools.ant.helper.DefaultExecutor.executeTargets(DefaultExecutor.java:41)
   [jasper] 	at org.apache.tools.ant.Project.executeTargets(Project.java:1248)
   [jasper] 	at org.apache.tools.ant.Main.runBuild(Main.java:851)
   [jasper] 	at org.apache.tools.ant.Main.startAnt(Main.java:235)
   [jasper] 	at org.apache.tools.ant.launch.Launcher.run(Launcher.java:280)
   [jasper] 	at org.apache.tools.ant.launch.Launcher.main(Launcher.java:109)

If 7.0.58 is replaced by 7.0.57 then the repeat runs without any exception and with complete output.

The problem seems to be the cleanup of the tldLocationsCache initialization in revision 1645615, partially backported from revision 1541041, since it's still used by JspCompilationContext.getTldLocation.

Possibly the fix is as easy as bringing back the initialization line.