title: Function [of:format1] not found error after obfuscating
body: <p>I have obfuscated my project using ProGuard. When I try to run it, the pages that use the taglib <code>xmlns:of="http://omnifaces.org/functions"</code> cause the following error:  <code>Function [of:format1] not found</code>.
  I figured I should somehow keep the taglib in ProGuard configurations, but I don't know how.
  Below is the full stack trace of the error:</p>
  
  <pre><code>javax.el.ELException: Function [of:format1] not found
      at org.apache.el.lang.ExpressionBuilder.visit(ExpressionBuilder.java:219)
      at org.apache.el.parser.SimpleNode.accept(SimpleNode.java:142)
      at org.apache.el.lang.ExpressionBuilder.prepare(ExpressionBuilder.java:161)
      at org.apache.el.lang.ExpressionBuilder.build(ExpressionBuilder.java:179)
      at org.apache.el.lang.ExpressionBuilder.createValueExpression(ExpressionBuilder.java:242)
      at org.apache.el.ExpressionFactoryImpl.createValueExpression(ExpressionFactoryImpl.java:67)
      at com.sun.faces.facelets.tag.TagAttributeImpl.getValueExpression(TagAttributeImpl.java:412)
      at com.sun.faces.facelets.tag.TagAttributeImpl.getValueExpression(TagAttributeImpl.java:378)
      at com.sun.faces.facelets.tag.jsf.ComponentRule$ValueExpressionMetadata.applyMetadata(ComponentRule.java:107)
      at com.sun.faces.facelets.tag.MetadataImpl.applyMetadata(MetadataImpl.java:81)
      at javax.faces.view.facelets.MetaTagHandler.setAttributes(MetaTagHandler.java:129)
      at javax.faces.view.facelets.DelegatingMetaTagHandler.setAttributes(DelegatingMetaTagHandler.java:102)
      at com.sun.faces.facelets.tag.jsf.ComponentTagHandlerDelegateImpl.doNewComponentActions(ComponentTagHandlerDelegateImpl.java:491)
      at com.sun.faces.facelets.tag.jsf.ComponentTagHandlerDelegateImpl.apply(ComponentTagHandlerDelegateImpl.java:178)
      at javax.faces.view.facelets.DelegatingMetaTagHandler.apply(DelegatingMetaTagHandler.java:120)
      at javax.faces.view.facelets.CompositeFaceletHandler.apply(CompositeFaceletHandler.java:95)
      at javax.faces.view.facelets.DelegatingMetaTagHandler.applyNextHandler(DelegatingMetaTagHandler.java:137)
      at com.sun.faces.facelets.tag.jsf.ComponentTagHandlerDelegateImpl.apply(ComponentTagHandlerDelegateImpl.java:202)
      at javax.faces.view.facelets.DelegatingMetaTagHandler.apply(DelegatingMetaTagHandler.java:120)
      at org.springframework.faces.security.FaceletsAuthorizeTagHandler.apply(FaceletsAuthorizeTagHandler.java:80)
      at javax.faces.view.facelets.CompositeFaceletHandler.apply(CompositeFaceletHandler.java:95)
      at javax.faces.view.facelets.DelegatingMetaTagHandler.applyNextHandler(DelegatingMetaTagHandler.java:137)
      at com.sun.faces.facelets.tag.jsf.ComponentTagHandlerDelegateImpl.apply(ComponentTagHandlerDelegateImpl.java:202)
      at javax.faces.view.facelets.DelegatingMetaTagHandler.apply(DelegatingMetaTagHandler.java:120)
      at javax.faces.view.facelets.CompositeFaceletHandler.apply(CompositeFaceletHandler.java:95)
      at javax.faces.view.facelets.DelegatingMetaTagHandler.applyNextHandler(DelegatingMetaTagHandler.java:137)
      at com.sun.faces.facelets.tag.jsf.ComponentTagHandlerDelegateImpl.apply(ComponentTagHandlerDelegateImpl.java:202)
      at javax.faces.view.facelets.DelegatingMetaTagHandler.apply(DelegatingMetaTagHandler.java:120)
      at org.springframework.faces.security.FaceletsAuthorizeTagHandler.apply(FaceletsAuthorizeTagHandler.java:80)
      at com.sun.faces.facelets.tag.ui.DefineHandler.applyDefinition(DefineHandler.java:106)
      at com.sun.faces.facelets.tag.ui.CompositionHandler.apply(CompositionHandler.java:206)
      at com.sun.faces.facelets.impl.DefaultFaceletContext$TemplateManager.apply(DefaultFaceletContext.java:395)
      at com.sun.faces.facelets.impl.DefaultFaceletContext.includeDefinition(DefaultFaceletContext.java:366)
      at com.sun.faces.facelets.tag.ui.InsertHandler.apply(InsertHandler.java:111)
      at javax.faces.view.facelets.CompositeFaceletHandler.apply(CompositeFaceletHandler.java:95)
      at com.sun.faces.facelets.tag.ui.CompositionHandler.apply(CompositionHandler.java:194)
      at com.sun.faces.facelets.compiler.NamespaceHandler.apply(NamespaceHandler.java:93)
      at com.sun.faces.facelets.compiler.EncodingHandler.apply(EncodingHandler.java:87)
      at com.sun.faces.facelets.impl.DefaultFacelet.include(DefaultFacelet.java:312)
      at com.sun.faces.facelets.impl.DefaultFacelet.include(DefaultFacelet.java:371)
      at com.sun.faces.facelets.impl.DefaultFacelet.include(DefaultFacelet.java:350)
      at com.sun.faces.facelets.impl.DefaultFaceletContext.includeFacelet(DefaultFaceletContext.java:199)
      at com.sun.faces.facelets.tag.ui.IncludeHandler.apply(IncludeHandler.java:124)
      at com.sun.faces.facelets.tag.ui.InsertHandler.apply(InsertHandler.java:116)
      at javax.faces.view.facelets.CompositeFaceletHandler.apply(CompositeFaceletHandler.java:95)
      at javax.faces.view.facelets.DelegatingMetaTagHandler.applyNextHandler(DelegatingMetaTagHandler.java:137)
      at com.sun.faces.facelets.tag.jsf.ComponentTagHandlerDelegateImpl.apply(ComponentTagHandlerDelegateImpl.java:202)
      at javax.faces.view.facelets.DelegatingMetaTagHandler.apply(DelegatingMetaTagHandler.java:120)
      at javax.faces.view.facelets.CompositeFaceletHandler.apply(CompositeFaceletHandler.java:95)
      at com.sun.faces.facelets.tag.jsf.core.ViewHandler.apply(ViewHandler.java:225)
      at javax.faces.view.facelets.CompositeFaceletHandler.apply(CompositeFaceletHandler.java:95)
      at com.sun.faces.facelets.compiler.NamespaceHandler.apply(NamespaceHandler.java:93)
      at com.sun.faces.facelets.compiler.EncodingHandler.apply(EncodingHandler.java:87)
      at com.sun.faces.facelets.impl.DefaultFacelet.include(DefaultFacelet.java:312)
      at com.sun.faces.facelets.impl.DefaultFacelet.include(DefaultFacelet.java:371)
      at com.sun.faces.facelets.impl.DefaultFacelet.include(DefaultFacelet.java:350)
      at com.sun.faces.facelets.impl.DefaultFaceletContext.includeFacelet(DefaultFaceletContext.java:199)
      at com.sun.faces.facelets.tag.ui.CompositionHandler.apply(CompositionHandler.java:174)
      at com.sun.faces.facelets.compiler.NamespaceHandler.apply(NamespaceHandler.java:93)
      at com.sun.faces.facelets.compiler.EncodingHandler.apply(EncodingHandler.java:87)
      at com.sun.faces.facelets.impl.DefaultFacelet.apply(DefaultFacelet.java:161)
      at com.sun.faces.application.view.FaceletViewHandlingStrategy.buildView(FaceletViewHandlingStrategy.java:1006)
      at com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:99)
      at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
      at com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:219)
      at javax.faces.webapp.FacesServlet.service(FacesServlet.java:659)
      at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
      at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
      at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
      at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
      at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
      at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:317)
      at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:127)
      at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:91)
      at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
      at org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:114)
      at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
      at org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:137)
      at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
      at org.springframework.security.web.authentication.AnonymousAuthenticationFilter.doFilter(AnonymousAuthenticationFilter.java:111)
      at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
      at org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:170)
      at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
      at org.springframework.security.web.savedrequest.RequestCacheAwareFilter.doFilter(RequestCacheAwareFilter.java:63)
      at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
      at org.springframework.security.web.authentication.www.BasicAuthenticationFilter.doFilterInternal(BasicAuthenticationFilter.java:158)
      at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
      at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
      at org.springframework.security.web.authentication.AbstractAuthenticationProcessingFilter.doFilter(AbstractAuthenticationProcessingFilter.java:200)
      at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
      at org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:116)
      at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
      at org.springframework.security.web.header.HeaderWriterFilter.doFilterInternal(HeaderWriterFilter.java:64)
      at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
      at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
      at org.springframework.security.web.context.request.async.WebAsyncManagerIntegrationFilter.doFilterInternal(WebAsyncManagerIntegrationFilter.java:56)
      at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
      at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
      at org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:105)
      at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
      at org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:214)
      at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:177)
      at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:346)
      at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:262)
      at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
      at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
      at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:199)
      at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
      at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:478)
      at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140)
      at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:81)
      at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:650)
      at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87)
      at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342)
      at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:803)
      at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
      at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:868)
      at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1459)
      at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
      at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
      at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
      at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
      at java.lang.Thread.run(Thread.java:748)
  </code></pre>
  
  <p>Thank you in advanced.</p>