unknown comparison failure occurs with xtext formatter - formatting

Question

I'm customizing the xtext formatter of my dsl and whist testing I get a weird comparison failure I don't understand.
Here's the relevant part of my grammar :
EisModel:
'project' '=' project_name=STRING ';'
'plcname' '=' plc_name=STRING ';'
'author' '=' author_name=STRING ';'
testcases+=Testcase*;
Testcase:
"testcase" testcase_name=ID '{'
testblock=Testblock?
'}';
Testblock:
'testActive' '=' testActive=BoolConstant ';'
'blockType' '=' blockType=BlockConstant ';'
'description' '=' description=STRING ';'
define=DefineBlock?;
BoolConstant:
value=('true' | 'false');
BlockConstant:
value=('FC' | 'FB');
And the comparison failure I get, I assume, has something to do with a problem regarding a terminal rule, since I am not doing anything extraorinary in the formatter.
This is the expected code of the JUnit failure trace:
74 4 S "true" BoolConstant:value='true'
78 0 H
78 1 S ";" Testblock:(';' )
79 2 H "\n\t" Whitespace:TerminalRule'WS'
81 9 S "blockType" Testblock:'blockType'
90 1 H " " Whitespace:TerminalRule'WS'
91 1 S "=" Testblock:( '=' )
92 1 H " " Whitespace:TerminalRule'WS'
93 2 S "FC" BlockConstant:value='FC'
And this the actual code:
B BoolConstant Testblock:testActive=BoolConstant path:Testblock/testActive=Testcase/testblock=EisModel/testcases[0]
74 4 S "true" BoolConstant:value='true'
E BoolConstant Testblock:testActive=BoolConstant path:Testblock/testActive=Testcase/testblock=EisModel/testcases[0]
78 0 H
78 1 S ";" Testblock:(';' )
79 2 H "\n\t" Whitespace:TerminalRule'WS'
81 9 S "blockType" Testblock:'blockType'
90 1 H " " Whitespace:TerminalRule'WS'
91 1 S "=" Testblock:( '=' )
92 1 H " " Whitespace:TerminalRule'WS'
B BlockConstant Testblock:blockType=BlockConstant path:Testblock/blockType=Testcase/testblock=EisModel/testcases[0]
93 2 S "FC" BlockConstant:value='FC'
E BlockConstant Testblock:blockType=BlockConstant path:Testblock/blockType=Testcase/testblock=EisModel/testcases[0]
The difference revolves around the lines 74 and 93.
And I don't know what is going wrong or even where I could tweak anything.
Could anyone please help?
Here's the test:
#Test def void testTestblock() {
assertFormatted[
toBeFormatted = '''
project="proj";plcname="name";author="Bob";
testcase One {testActive = true ; blockType = FC ;
description = "string" ; }
'''
expectation = '''
project = "proj";
plcname = "name";
author = "Bob";
testcase One {
testActive = true;
blockType = FC;
description = "string";
}
'''
]
}
The bug even occurs if I comment out my code in the formatter class which extends AbstractFormatter2, so I'll omit that here.

Answer 1

this sounds like a bug to me. please report it at https://github.com/eclipse/xtext-core
workaround:
BoolConstant:
value=BooleanValue;
BlockConstant:
value=BlockValue;
BlockValue:"FC"|"FB";
BooleanValue: "true"|"false";

Answer 2

Here's a little bit more of the grammar:
EisModel:
'project' '=' project_name=STRING ';'
'plcname' '=' plc_name=STRING ';'
'author' '=' author_name=STRING ';'
testcases+=Testcase*;
Testcase:
"testcase" testcase_name=ID '{'
testblock=Testblock?
'}';
Testblock:
'testActive' '=' testActive=BoolConstant ';'
'blockType' '=' blockType=BlockConstant ';'
'description' '=' description=STRING ';'
define=DefineBlock?;
BoolConstant:
value=BooleanValue;
BlockConstant:
value=BlockValue;
BlockValue:
'FC' | 'FB';
BooleanValue:
'true' | 'false';
DefineBlock:
'define' '{' direction=DirectionBlock '}' teststeps+=TeststepBlock*;
DirectionBlock:
input=Input & inout=InOut? & output=Output;
Input:
name='input' '[' inputVariables+=Variables* ']';
Output:
name='output' '[' outputVariables+=Variables* ']';
InOut:
name='inout' '[' inoutVariables+=Variables* ']';
And here another comparison failure.
expected:
123 5 S "input" Input:name='input'
128 0 H
128 1 S "[" Input:'['
129 0 H
129 1 S "]" Input:']'
130 0 H
130 6 S "output" Output:name='output'
136 0 H
136 1 S "[" Output:'['
137 0 H
137 1 S "]" Output:']'
actual:
B Input'input' DirectionBlock:input=Input path:DirectionBlock/input=DefineBlock/direction=Testblock/define=Testcase/testblock=EisModel/testcases[0]
123 5 S "input" Input:name='input'
128 0 H
128 1 S "[" Input:'['
129 0 H
129 1 S "]" Input:']'
E Input'input' DirectionBlock:input=Input path:DirectionBlock/input=DefineBlock/direction=Testblock/define=Testcase/testblock=EisModel/testcases[0]
130 0 H
B Output'output' DirectionBlock:output=Output path:DirectionBlock/output=DefineBlock/direction=Testblock/define=Testcase/testblock=EisModel/testcases[0]
130 6 S "output" Output:name='output'
136 0 H
136 1 S "[" Output:'['
137 0 H
137 1 S "]" Output:']'
E Output'output' DirectionBlock:output=Output path:DirectionBlock/output=DefineBlock/direction=Testblock/define=Testcase/testblock=EisModel/testcases[0]
The differences are now around the lines 123-129 and 130-137.
Edit
After activating the formatter within the editior, I received an error message which I don't understand. Maybe someone else does:
Message:
Unhandled event loop exception
Exception Stack Trace:
java.lang.StackOverflowError
at com.google.common.collect.RegularImmutableMap.get(RegularImmutableMap.java:123)
at com.google.common.collect.RegularImmutableMap.get(RegularImmutableMap.java:115)
at org.eclipse.xtext.formatting2.regionaccess.internal.NodeModelBasedRegionAccess.regionForEObject(NodeModelBasedRegionAccess.java:49)
at org.eclipse.xtext.formatting2.regionaccess.internal.NodeModelBasedRegionAccess.regionForEObject(NodeModelBasedRegionAccess.java:22)
at org.eclipse.xtext.formatting2.AbstractFormatter2.isInRequestedRange(AbstractFormatter2.java:358)
at org.eclipse.xtext.formatting2.AbstractFormatter2.shouldFormat(AbstractFormatter2.java:423)
at org.eclipse.xtext.formatting2.internal.FormattableDocument.format(FormattableDocument.java:186)
at org.example.eis.formatting2.EisFormatter._format(EisFormatter.java:224)
at org.example.eis.formatting2.EisFormatter.format(EisFormatter.java:346)
A look at the java classes:
223 protected void _format(final DirectionBlock directionblock, #Extension final IFormattableDocument document) {
224 document.<DirectionBlock>format(directionblock);
225 }