An error occurred while processing the template. 
?substring(...) argument #1 had invalid value: The index must be at least 0, but was -1.

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FTL stack trace ("~" means nesting-related):
	- Failed at: #assign journalArticleId = themeDispl...  [in template "20099#20125#42414" at line 4, column 1]
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1<#assign url = themeDisplay.getURLCurrent() 
2index = 0/> 
3 
4<#assign journalArticleId = themeDisplay.getURLCurrent()?substring(themeDisplay.getURLCurrent()?index_of("id="))+3/> 
5 
6 
7<#assign indexInizio = themeDisplay.getURLCurrent()?index_of("id=")+3> 
8<#assign indexFine= themeDisplay.getURLCurrent()?index_of("&from=")> 
9  
10<#assign journalArticleId = themeDisplay.getURLCurrent()?substring(indexInizio, indexFine)/> 
11 
12  
13 
14<#if journalArticleId?has_content> 
15 
16<#if entries?has_content> 
17	<#list entries as curEntry> 
18	  
19	  <#if curEntry.getEntryId() == journalArticleId?number> 
20		  
21					<#assign 
22						assetRenderer = curEntry.getAssetRenderer() 
23						entryTitle = htmlUtil.escape(assetRenderer.getTitle(locale)) 
24						docXml = saxReaderUtil.read(assetRenderer.getArticle().getContent()) 
25						dataCreazione = curEntry.getCreateDate()  
26						/> 
27					  
28						<#assign fields = assetRenderer.getDDMFormValuesReader().getDDMFormValues().getDDMFormFieldValues()/> 
29								<#list fields as currentField> 
30												<#if currentField.getDDMFormField().getFieldReference()=='titolo'> 
31													<#assign titolo=currentField.getValue().getString(themeDisplay.getLocale()) />												  
32												</#if> 
33												<#if currentField.getDDMFormField().getFieldReference()=='areaDiTesto'> 
34													<#assign contenutoArticle=currentField.getValue().getString(themeDisplay.getLocale()) /> 
35												</#if> 
36												  
37								</#list> 
38						 
39						<main class="container ct-main" > 
40            <h1 class="title">${titolo}</h1> 
41            <div id="ctPagina"> 
42                <div class="text-wrapper"> 
43                		${contenutoArticle} 
44								</div> 
45            </div> 
46        </main> 
47		</#if> 
48  </#list> 
49</#if> 
50</#if>