Using @Saxon-EE 9.8.0.2J@ from the command line, I get an error message "No watch found for ..." with various attempts to convert an XSLT 2.0 @xsl:for-each-group select="*" group-starting-with="h1"@ to streaming, needing a body of @xsl:for-each-group that needs to both process the @current-group()@ as well as check the non-existance of more than one item in the group.

As some bugs related to streamed grouping have been resolved after 9.8.0.2 I file this here in the forum and not as a bug so that you can check whether the latest fixes fix this problem as well.

Here is one example:

When run against the input

	

		<title>Name1</title>
	
	

		<title>Name2</title>
	
	Test1
	Test2
	

		<title>Name3</title>
	
	Test3
	Test4

Saxon outputs

Error on line 4 column 10 of test2017062601.xml:
  No watch found for current-group()[2]

When I switch off streaming by setting the static parameter @STREAMABLE=0@ I get the correct, wanted result:

   
      

         <title>Name1</title>
      
      
   
   
      

         <title>Name2</title>
      
      Test1
      Test2
   
   
      

         <title>Name3</title>
      
      Test3
      Test4
   

I have tried various variations of the @xsl:fork@, but all lead to similar error messages, like

giving "No watch found for fn:subsequence(...)" or like

giving "No watch found for tail(current-group())".

The only approach that worked is not using @xsl:fork@ but instead use a @copy-of(current-group())@ with a variable